3

• 1. Long-leaf pine.
• 2. Coastal prairie.
• 3. Fayette prairie.
• 4. Mesquite-chaparral.
• 5. Coastal sand dunes.
• 6. Granitic soil with oak and mesquite.
• 7. Edwards Plateau, oak-cedar.
• 8. Mountains: Guadalupe, Davis, Glass, Cathedral, Chenati, Chisos.
• 9. Live-oak, mesquite and Acacia on short grass.
• 10. Trans-Pecos: Sotol lechuguilla.
• 11. Sandy south plains.
• 12. High plains.
• 13. Mesquite-grassland.
• 14. Western cross timbers, oak-hickory.
• 15. Eastern cross timbers, oak-hickory.
• 16. Oak-hickory.
• 17. Loblolly pine, short-leaf pine and oak-hickory.
• 18. Black land prairie.

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5

7

8

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• Page
• FOREWORD xiii
• INTRODUCTION xv
• TEXAS VEGETATION 1
  • VEGETATIONAL REGIONS
    • REGION 1 LONG-LEAF PINE 2
    • REGION 2 THE COASTAL PRAIRIE 7
    • REGION 3 THE FAYETTE PRAIRIE 9
    • REGION 4 MESQUITE-CHAPARRAL 10
    • REGION 5 COASTAL SAND DUNES 11
    • REGION 6 OAK-HICKORY-MESQUITE 12
    • REGION 7 THE EDWARDS PLATEAU 14
    • REGION 8 THE MOUNTAINS 17
    • REGION 9 LIVE OAK MESQUITE SAVANNA 21
    • REGION 10 SOTOL-LECHUGUILLA 22
    • REGION 11 THE SANDY SOUTH PLAINS 25
    • REGION 12 THE HIGH PLAINS 27
    • REGION 13 THE MESQUITE-GRASSLAND 30
    • REGION 14 THE WESTERN CROSS TIMBERS 31
    • REGION 15 THE EASTERN CROSS TIMBERS 33
    • REGION 16 OAK-HICKORY 35
    • REGION 17 THE PINE-OAK FOREST 37
    • REGION 18 THE BLACKLAND PRAIRIE 39
• DISTRIBUTION LIST OF FERNS & SEED PLANTS
  • FERNS 41
  • SEED PLANTS 42
• ECOLOGY DEFINED 74

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• Page
• PLATE I iii
• MR. DRUMMOND'S PHLOX Frontispiece
  • From the original print (1835)
• LONG-LEAF PINE 4
• SEEDLING LONG-LEAF 5
• SALT GRASS 5
• HUAJILLO ETC 6
• LOST MINE PEAK, CHISOS MOUNTAINS 6
• MESQUITE-PRICKLY PEAR, PALO PINTO COUNTY 13
• MOUNTAIN LIVE OAK, DAVIS MOUNTAINS 15
• WESTERN YELLOW PINE, DAVIS MOUNTAINS 15
• WHITE SAGE AND MESQUITE, NEAR MONAHANS 16
• BALM CYPRESS I N CADDO LAKE 16
• OCOTILLO 23
• SLENDER BEAR GRASS AND YUCCA, BREWSTER COUNTY 23
• CRUST OF SALT NEAR BROWNFIELD 24
• PYGMY FOREST OF HAVARD'S OAK 26
• OAK-HICKORY NEAR TEXARKANA 34
• POST OAK NEAR REFUGIO 34
• WESTERN CROSS TIMBERS 40

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13

IT has long been a cherished ideal of the Texas Academy of Science to give to the public and to scientists a series of treatises on the natural history of the state: the animals, the plants, the rocks, minerals, soils, geography and climate. The preparation of such a series of treatises, involving long periods of research and the use of substantial sums of money, must necessarily extend over many years. Several valuable scientific articles of more than casual interest have been published by the Academy in the ten years of its revived life since 1929.

In order to prepare the way for the more pretentious series of treatises which it is hoped will some day be forthcoming, the Academy has now carried out a plan which in a measure achieves its ideal. A group of some thirty brief summary articles has been prepared to cover the field of the more interesting and important subjects and these will now be published in volume form. These articles are written in plain language so that both scientists and the public may profit by their account of the present state of knowledge in this field, pending the time when investigators may be stimulated to complete the full scientific treatises which the Academy hopes to see published on the realm of Texas.

Since it takes some time to prepare for printing and publication even this series of brief articles, the Academy has arranged with the publishers to offer, as advance chapters, one by one as they can be gotten ready, the most attractive and timely articles of the thirty. It is planned for these chapters to appear as individual brochures at intervals of a few weeks while the collected work is being prepared,   

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and so long as there seems to be a public demand for them in this form.

This first brochure in the series, "The Vegetation of Texas," is one which seems to be unique among the "tree books" and "flower books" of the state in that it is truly neither a tree book nor a flower book, but describes the entire vegetational cover of Texas. This extensive subject is covered by individual vegetational regions, with the characteristic groupings of the more conspicuous plants in each described and illustrated by photographs taken by the author.

Such a description of vegetational regions has practical scientific and economic uses too numerous to mention, besides serving as a guide to nature study and vacational and scenic expeditions and journeys.

Through the generosity of a friend of science in Texas, Mr. S. G. Drushel, of Edna, Texas, the Academy is able to present as a frontispiece a unique illustration in color. It is a reproduction by a new and unusually faithful process of the first color print of Phlox drummondii. ; The original print was published in 1835.

The Academy takes this opportunity of publicly thanking Mr. Drushel for this valuable contribution. This beautiful flower is more widespread in occurrence over the state than even the celebrated bluebonnet. Groups of flower lovers long advanced it as a rival of the bluebonnet for the honor of being officially designated the State Flower.

See discussion of Region 16.

Editorial Committee

W. ARMSTRONG PRICE,

Chairman

W. S. ADKINS

C. L. BAKER

J. T. PATTERSON

C. T. REED

B. C. THARP

W. M. WINTON

15

THERE is probably no group of organisms, and few, if any, science topics more interesting to layman and naturalist alike than are the plants. This general interest attaches, however, mainly to the flowering plants and ferns-the flowers and the trees-other types of plants being either so inconspicuous as to be essentially invisible to all except specialists, as in the case of the bacteria, or of simple and unromantic body form, such as the pond slimes or algae.

Most people take pride in knowing a certain number of the trees and flowers of their native region, if no others. Plants are particularly suited to field study and to collection. The plant is stationary, can not run away and hide, hence, does not have to be hunted or trapped with acquired skill and expensive apparatus. Plants pose for their pictures without exhibiting nervousness or self-consciousness. Through their beauty they inspire artists, poets and lovers, as few animals have ever done. Their only real competition is from the female of the human species, but they have throughout history been considered her chief adornment.

A beautifully colored flower book-besides its value to flower lovers and flower hunters-is a popular and decorative living-room table piece. It is not within the scope of this article to enter this field. Without greatly increasing the size of the book, the individual plants could not be treated descriptively with the detail and consideration which their beauty and general interest warrant. This task is left to other books. There is, however, a field in plant study which the editors of this series take pleasure in presenting to the   

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public; that is, the recognition and description of vegetational regions. Our author, a specialist and leader in this field, here gives us a brief sketch of the make up of the plant assemblages, or the vegetational physiognomy of each region.

That the vegetational regions here described are natural areas is indicated by the close harmony between these regions and the major provinces of Texas as defined by the soils, the outcropping rocks and sediments, the major physiographic subdivisions and the climatic zones.

The delineation and description of all such natural regions is one of the pressing tasks of the scientist, eminently in this generation, for it forms a basis for studies of population distribution, land use, erosion control, crop adaptability, and other fundamental human problems. Through these lines of research the future of much of the life and prosperity of the state will be determined; upon them may be based economic studies in practically all fields.

The lists of genera and families of the Texas ferns and flowering plants extend the information on the vegetational make-up of the different regions. These are amplified, for many plants listed, by further details of their life habitat.

The information given in this article on Texas vegetation forms the basic data of the plant ecology of Texas and is presented here in condensed form and comprehensive style from abundant data collected during many years by a large number of field workers and recorded in the herbarium of the University of Texas.

W. ARMSTRONG PRICE

1

ON the pages of this section the reader will find the following:

• 1. A map representing an attempt by the author to delineate his concept of the major vegetational regions of the state, eighteen in number.
• 2. A very brief summary account of the dominant features to be found in each region.
• 3. A list of genera of ferns and flowering plants (seed plants) to be found in the state, based on collections in the herbarium of the University of Texas, giving the regions in which each has been found. This list, necessarily incomplete, includes several genera not heretofore of published record for Texas.
• 4. Such illustrations as limitations will permit.

By these means it is hoped to convey to the mind of one not familiar with the various regions some idea of their vegetational physiognomy and principal constituents.

Vegetational physiognomy, the make-up of the vegetational assemblage.

2

THIS region is dominated by the pine which gives it name. It is a sandy region of low-lying hills interspersed with "crawfish" flats, subject to 45 to 50 inches of rainfall and traversed by numerous creeks and rivers. Under such conditions, marshes and swamps are common.

Long-leaf pine formerly dominated both hills and craw-fish flats; but most of the virgin timber has long since been cut and the slash carelessly allowed to burn. At present one's eye is frequently greeted by vast stretches of grasses and flowering herbs thickly flecked with blackened stumps, remains of the former forest. Occasional rejected relict trees stand sparsely scattered, raising wispy crowns atop long thin trunks. Though dejected and sorrowful of aspect, they furnish the seed with which ultimately, under protection from grass fires, it will yet be possible to restore the beauty of the original virgin forest. Even now intelligent and foresighted owners have an abundance of local second growth timber on protected plots, showing that it is practicable to reforest the whole region. Of recent years the state itself through its State Forester's Office has inaugurated an educational campaign resulting in the enactment of laws which now penalize careless fire setting and provide for an effective look-out and fire-fighting system.

In addition to long-leaf, both short-leaf and loblolly pine are found in the region; but in such minor role as to be negligible. Along stream "bottoms" of silty texture, rich with humus, numerous hardwoods occur. Swamps of tupelo and bald cypress, formerly common, have largely been destroyed by lumbering operations. Lofty trees of willow-oak, overcup oak, southern pin oak, white, red, yellow, basket and other oaks occur; as do also beautiful groves of beech and magnolia. Along stream banks birch is not uncommon.

Slash, the discarded branches and debris.

"Bottoms"; that is, flood plains.

3

Small trees are: flowering dogwood, fringe-tree, red haw, black haw, holly, yaupon and redbud. These together with Azaleas, trumpet creeper (Bignonia), yellow jessamine, Wistaria, erids, pitcher plants, buckeye, violets, orchids, Iris, Phlox, jack-in-the-pulpit, mustard and other such growth make the forest resplendent with bloom from February to May. Several sorts of evergreen smilax spread their beautiful green canopies high among the loftiest tree crowns.

In the summer and fall, huckleberry, both bush and tree, Callicarpa, wax myrtle, Virginia-willow, witch hazel, scrophs of various sorts, milkworts, composites, yellow eyed grass, lilies, spider-lily and legumes, all combine to render the open woodlands and shaded swamp florally attractive.

The upland sandy soil, allowing free percolation of the abundant rainfall, is thoroughly leached of its soluble plant nutrients, and is therefore quite sterile and unprofitable for cultivation. To decrease still further its adaptability to such use, it is a perfect haven for one of the worst pests a farmer ever had to face-crab-grass. This most pernicious of all native weeds has a seasonal growth that coincides exactly with that of field crops; and during wet years the best of farmers lose a part of their crops in their futile fight against it. Even in ordinary years, the difficulty is so great as to reduce strongly the "acreage per hand" in this region as compared with regions 7, 12, 13 and 18 (See map, Plate 1). With the application of fertilizer, however, an abundance of vegetable and truck crops can be raised locally. Also, numerous tracts of considerable acreage and great natural richness are found bordering creek and river bottoms.

When all is said, however, far the best use to which these millions of acres of cut-over lands can be put is to restore to them the forests of long-leaf pine with which they were originally clothed and to lumber the resulting forests by processes so controlled as to preserve them virtually intact. This would appear possible only under government ownership, since such methods as "

Nutrients, nourishing substances.

4

would preserve the forests would not promptly yield to the private individual the whole of the potential return. Nor is it attractive to an individual, or even to a corporation, to embark on a planting program the harvesting of the first fruits of which cannot be expected to begin until after the planters themselves are dead.

Certainly society, represented by the government, should acquire and preserve at least one sizeable tract of the few remaining stands of virgin timber in this region, in order to preserve it as a fragmentary example of the natural splendor and beauty that used to be the East Texas "Piney" ; Woods.

"Piney" instead of pine, for the adjective derived from the noun pine, is in almost universal use among Texas scientists and the native population. Elsewhere regarded as a colloquialism, it has local good standing.

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6

7

WHILE the region as a whole is characterized by vast stretches of level grassland, constituted by sage, carpet, salt, paspala, panic, dropseed, grama grass, and other grasses, it bears local areas of well developed woodland. These occur

• (1) upon sandy ridges, and
• (2) along stream courses.

Water deficiency south of Kleberg County is so great as to prevent dryland farming except upon soil in which a particularly favorable texture gives a maximum of water conservation, as about Raymondville and Lyford. The tight silty soil of the Rio Grande flood plain is successfully cultivated only under irrigation, but its great richness, combined with a subtropical climate has produced an unsurpassed horticultural-vegetable and citrus-region.

It is a fact probably few realize, that aside from the Trinity and the San Jacinto, no Texas stream merges with salt water through a wooded bottom. All have their confluence through marshlands composed of giant reeds, cat-tails and sedges. It is a grotesquely interesting sight to view from a distance an ocean liner bound for Houston or Beaumont apparently sailing majestically across the prairie! Bluff banks of sufficient elevation to supply the essential degree of drainage, together with a red or yellow sand-clay soil, are apparently responsible for the two exceptional woodland cases mentioned.

Levelness, impervious substratum, and heavy annual rainfall, "

Dominants, conspicuous and abundant members of a group of plants (flora) or animals (fauna).

8

combine to render farming north of Port Lavaca, in general, hazardous. Exceptionally rich and favorable local areas occur in Jackson, Matagorda and Brazoria counties. The area, however, in general, is mostly devoted to grazing, and supports great numbers of cattle, in many of the herds Brahma blood being quite apparent. Between Port Lavaca and Kingsville, the annual rainfall is favorable for agriculture and this portion is largely under cultivation to cotton.

Shrubby Iva, Baccharis and wax myrtle are common as far south as Calhoun County, the last named giving such character as to have prompted the name "myrtle prairie," by which much of the northern portion of the Coastal Prairie is commonly known. Conspicuous flowering herbs are arrow-head, spider-lily, blue-eyed grass, pink Texas star, Texas blue-bell, blue and yellow asters, firewheels, spurges, scrophs, daisies, wild beans, Coreopsis, morning-glory, wild onion, giant coneflower, and many others. Common weeds are various members of the rag-weed group, sunflowers, Crotons and others. Saline marshes and back-beaches have each their own flora, characterized, in general, by the fleshy succulence usual to such situations.

There is much evidence on record to indicate that the chaparral extends much farther up the coast now than it did a hundred years ago. This spread is due, apparently:

• (1) to intensive grazing, which, together with increased population, has eliminated prairie fires except under control on stretches of salt-grass; and
• (2) to the actual dissemination of the seed of mesquite, Acacia, and horsebean by livestock which find the pods of these plants quite palatable.

9

THIS region, so called because typically shown in Fayette County is not unlike the Coastal Prairie to the southwest except that it is somewhat farther from the coast and its topography is more rolling. Drainage is correspondingly more effective and agriculture more secure. The soil is the black clay or marl usual as a substratum in southeastern Texas grassland.

Vegetation is not essentially different from that of the adjacent Coastal Prairie. Buffalo-grass and curly mesquite are common sod-forming grasses which grow in open spaces among the taller bunch grasses-bluestems, drop-seed, Stipas, and others-subject to the control of the latter. When any tract in the region is ungrazed, the short grasses are so inconspicuous as to be easily overlooked; but grazing in even moderate intensity operates to favor them at the expense of the tall bunch grasses, with the result that the normal home grazing-lot or pasture with which most farms are provided has much the appearance of a Bermuda grass lawn. This is particularly true where mowing operations or a few sheep keep down broom weeds and spurges.

Czech and German colonists early settled much of the Fayette Prairie and their descendants constitute an important part of the thrifty and substantial citizenry of the state.

10

A previously stated, there is dependable evidence to indicate that the chaparral vegetation characteristic of this region is much more extensive than it previously was. Field-notes in the records of original surveys, however, indicate that dry, gravelly soils have always supported such a growth and that, as more and more intensive grazing held the grasses under greater and greater restraint, the "brush" has spread into adjacent more level and fertile areas which formerly supported an abundance of grasses. Prairie relicts are still sufficiently numerous and variant to indicate the stages of the progressive invasion by mesquite, Acacia, Texas ebony, thorny hackberry, crooked-bush, Zizyphus, Condalia, purple sage, and other species which compose the chaparral.

In the late winter and early spring the region is brilliant and delightful with color, fragrance and song as the brush bursts into blossom, and the multiplied thousands of cardinals and mockingbirds set about their annual home-making. Millions of bees, the while, garner rich stores of nectar.

Buffalo, grama, and curly mesquite constitute the chief range grasses of value, while most of the brush is valuable as browse for goats and sheep. At least one of the shrubs, Karwinskia, is poisonous and constitutes a menace. Bunch grasses are also found in situations favorable for water conservation. Other grasses, harsh, unpalatable and poor in nutritive elements, also occur-for example, Aristida. An abundance of flowering herbs, both annual and perennial, are seasonally found in those areas not subjected to the browsing of sheep and goats.

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THIS region comprises a strip of sand hills some 10 to 15 miles wide stretching across the northern portions of Kennedy, Brooks and Jim Hogg counties. They are characterized by scrub liveoak of varying height, either in mottes or in more or less continuous thickets. Interspersed with the scrubby oaks are a few much larger trees, while on more level stretches of somewhat finer soil texture mesquite is quite common.

Grasses are largely sages or bluestems, together with species of triple-awn, Chloris, bur-grass, dropseed, Triodia, and others of bunch habit. Except on level areas of decidedly tightish soils, curly mesquite and buffalo are not to be found. Both may be counted as essentially missing in the region.

Flowering herbs include milkweeds, mustards, Phlox, Coreopsis, cottony sunflower, Gaillardia, white, yellow and purple asters, daisies, evening primroses, poppies, four o'clocks, chickweeds, and others.

The various chaparral species characteristic of Region 4 are scantily present, but lend no character to the vegetational landscape. On the contrary they give one the impression of being, in effect, conspicuously absent.

Vegetation has stabilized the sand in most places, but here and there are localities in which the bare sand, freely blown by the wind, stands in characteristic dunes whose surfaces are beautifully ripple-marked. These occur abundantly along the coast and intermittently inland as far as Hebbronville.

Motte, French, clod, clump, hill or knoll. In the United States the term has long been applied to a clump of trees on a prairie. Such clumps commonly, but not exclusively, grow on knolls, and themselves resemble hills.

12

THE soil of this region is in general very coarse. Typically, it is composed of decomposed granite material, but it also includes, particularly along the margins, soils originating from the weathering of rocks representing all gradations of metamorphosis between crystalline rocks and sedimentary sandstone and limestone. The coarse granite soil typically overlies virtually unfissured massive granite whose uneven surface causes it to protrude more or less as solid, soil-less exposures grading from scant elevation and negligible area to hills several hundred feet high and several hundred acres in extent. Granite Mountain in Burnet County and Enchanted Rock in Llano County are conspicuous examples of major exposures.

The tighter, finer textured and more level portions of this region are characterized by mesquite with more or less of an admixture of Condalia, Zizyphus, Mimosa, cacti and a few other chaparral representatives, together with liveoak and cedar; looser, coarser soils of a rougher topography, by black jack and post oak with some hickory. These latter occur even in the deeper, soil-filled, seep-watered crevices between delaminate granite blocks split off from the massive sub-stratum of such protrusions as Enchanted Rock and Granite Mountain. In such locations the plants are quite scrubby and wholly devoid of any trunk below the branches-that is, the branches begin at the ground surface-and the height is seldom more than 12 or 15 feet. Among other woody species occurring well up on such hilly eminences are Mexican persimmon, buckeye (Aesculus arguta), Mexican buckeye and hackberry.

In deep narrow ravines opening to the northwest, well watered by continuous seepage and protected by steep slopes from the effect "

Crystalline rocks are old rocks altered during a former period of deepburial. They include both igneous (formerly molten) and sedimentary rocks.

Weathering of granite outcrops proceeds by the splitting off, or wearing off, of thin shells or "laminae." The result of such continued "delamination" is to produce smooth, oval, to round outcrop boulders and masses of granite.

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Benjamin Carroll Tharp of the prevailing southeast wind, post oak, blackjack and hickory are found in the tall growth-habit characteristic of them in extreme East Texas and Louisiana. A dense stand of these tall slender individuals within a stone's throw of the scrub growth of the same species on the exposed wind swept sides of Enchanted Rock gives startling evidence of the combined effects upon the form and appearance of vegetation of wind, evaporation and of scant versus abundant soil moisture.

Grasses of this region include-among others-sage, or bluestems, dropseeds, triple-awn, needle and grama grass. In the tighter soils are found the buffalo, and perhaps the curly mesquite grass. Flowering herbs are: mustards, mints, morning-glories, poppies, four o'clocks, Phlox, evening primroses, Oxalis, mallows, milkweeds, spurges, bluebells, cucurbits, Coreopsis, dayflowers, Tradescantias, bladderworts, plantains, gentians, daisies, asters, sunflowers, firewheels, nightshades, and numerous others.

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THE southern portion of this region, below the middle of Burnet County, is characterized by the bold limestone hills which constitute the Balcones Escarpment and which support a vegetation featured by Spanish oak, scrub liveoak, shinoak and Mexican cedar. North of Burnet County broad fertile valleys lie between prominent limestone hills, the latter being covered by essentially the same vegetation as the bolder hills to the south. A noticeable correlation exists in many regions between an exposed geologic stratum and its vegetational dominants. For example, Spanish oak here characterizes the Walnut Springs limestone; an open stand of cedar, the terraces of the Glenrose; liveoak and cedar, the Edwards. Stream courses are marked throughout by the presence of pecan, bur oak, elm, hackberry, liveoak, and others. Many high sandy stream terraces are covered by mesquite, which is scant in the uplands of the region; presumably because the soil overlying the hard unweathered limestone is too thin to permit the growth of the long tap-root which is characteristic of, and apparently essential to, this plant.

Grasses are sage (including the little bluestem), grama, needle, dropseed, buffalo, running mesquite, curly mesquite, Muhlenbergia, Triodia, triple-awn, and many other less prominent ones. Johnson Grass is a common pest on cultivated ground.

Fox-glove, mints, sages, winecups and other mallows, Indian paintbrush, Roemer's Phlox, verbenas, bush honeysuckle, redbud, Mexican buckeye, Texas mountain laurel, common buckeye, plum, wild cherry, mountain daisy, and many of its relatives, firewheels, Coreopsis, Thelesperma, pink, white and yellow evening primroses, mustards, Clematis, buttercups, Anemones, carrots, squaw-weeds, dock, and a riot of other flowering herbs and shrubs produce unsurpassable richness of spring color.

In general the southern portion of this region is a sheep, goat and cattle country; the northern being divided between farming on the fertile valley land and grazing on the rougher unarable hills.

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THE following paragraphs are quoted from the introduction to the "Vegetation in Chisos Mountains," ; based upon investigations made during the summers of 1931 and 1932. While applying specifically to the Chisos, it has general application also to the Davis, Guadalupe, Chenati, and other ranges, in proportion to their altitude and topography. Curiously, the Arizona cypress and Douglas spruce appear not to occur elsewhere in Texas besides the Chisos. Investigation of all the canyons leading down from the Davis Mountains' highest peak, Mt. Livermore, by L. C. Hinckley, has failed to reveal either of these species and neither is recorded, so far as I know from any other Texas location.

"The upper mountains are watered by springs and, in summer, normally, by almost daily afternoon rains. The plain is dry, for it receives little rain and has for the most part a high percentage of run-off, due in part to scant vegetation, in part to the nature of the soil, and in part to the torrential nature of precipitation. Only three of the upper waterways run normally. These are reduced to dry creek beds before they reach the foothills, and water runs in their lower reaches only after torrential rains. Grazing by sheep and goats is quite extensive in the foothills, but because of predatory animals is scant in the mountains.

"The vegetational physiognomy, like that of the remainder of the Trans-Pecos area, bears a close resemblance to the vegetation of Mexico. Desert shrubs such as sotol (Dasylirion), Agave, Yucca, ocotillo (Fouquiera), creosote bush (Larrea), and others, occur in great abundance upon the plains and foothills, extending, on drier slopes, even to altitudes of 6000 feet. Several Mexican species of needle grass (Stipa), triple-awn grass (Aristada) and other genera of grasses are important constituents of the various vegetational communities. Many other Mexican plants of lesser importance also occur.

Transactions of the Texas Academy of Science, Vol. XX., for 1935.1936; p. 6.

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"The relation of the vegetation to that of the Rocky Mountains is indicated by the occurrence of a number of relatively northern plants. Of these, Western yellow pine (Pinus brachyptera), Arizona cypress (Cupressus arizonica), Douglas spruce (Pseudotsuga mucronata), maple (Acer grandidentatum), quaking aspen (Populus tremuloides), and buckthorn (Rhamnus betulaefolia) are the more striking examples.

"The occurrence of a surprisingly great number of eastern plants, that is to say, plants which are found frequently east of the 98th meridian, is also interesting. Among the grasses are two gramas (Bouteloua hirsuta and B. curtipendula); three bluestems (Andropogon saccharoides, A. scoparius, and A. furcatus) and Gama (Tripsacum dactyloides). Among the shrubs are Clematis drummondii, hop-tree (Ptelea trifoliata), pallid hackberry (Celtis pallida), Mexican buckeye (Ungnadia speciosa), sumac (Rhus vixens and R. trilobata). White prickly poppy (Argemone platyceras), nightshades (Solanum rostratum, S. eleagnifolium), prostrate amaranth (Alternanthera repens) and sleepy catch-fly (Silene antirrhina) are common herbs.

"The surrounding plain averages about 3500 feet in altitude and slopes gradually away from the mountains. Most of the plains soil is derived from cretaceous rock and supports desert scrub such as Larrea, Flourensia, Condalia, Acacia, Mimosa, and Prosopis. In this are frequently found societies of ceniza (Leucophyllum texanum, L. minus), Parthenium incanum, and Porlieria angustifolia. Grasses are sparse in the plains, due in part to extreme over grazing and in part to desert conditions.

"On the low foothills and uneven outwash of the mountains are found relatively heavy growths of sotol (Dasylirion), lechuguilla (Agave lechuguilla), Yucca macrocarpa, ocotillo (Fouquiera), Condalia, and various cacti. The waterways support Mexican buckeye (Ungnadia), desert willow (Chilopsis linearis), western walnut (Juglans rupestris) , wild rose (Fallugia paradoxa), and Gregg's ash (Fraxinus greggii).

"In the higher foothills the shrubbery becomes denser and is less confined to waterways. On the lower mountain slopes are vast areas   

19

thickly covered with sumac (Rhus virens, R. trilobata), Gregg's ash (Fraxinus greggii), and occasional junipers, pinyon (Pinus edulis) and oaks. Of the oaks, Quercus grisea, Q. undulata, Q. emoryi and Q. gracilliformis are the more common. Quercus grisea, and Q. undulata are found in practically all types of situations in the upper mountains, but Q. gracilliformis requires more moisture and is consequently confined to arroyos, hollows, etc. The junipers are weeping (Juniperus flaccida), alligator bark (J. pachyphlaea), and one-seeded (J. monosperma).

"The vegetational composition of the tops of the mountains is relatively quite simple. Practically all mesas and gentle slopes bear a more or less dense growth of grey oak (Quercus grisea), Q. undulata, Pinus edulis, Juniperus flaccida, and J. pachyphlaea. Of the grass dominants Epicampes emersleyi and Stipa eminens are most important. Less important are Valota saccharata, Lycurus phleoides, and Oryzopsis fimbriata. The community becomes more wooded and less grassy on north exposures in proportion to the. declination of the slope. Some south slopes are almost devoid of trees and thickly covered with grass. The shrubs are mostly sumac (Rhus), sage (Salvia), lechuguilla (Agave lechuguilla), century plant (A. scabra), bear grasses (Nolina), Garrya ovata, and scrub oaks (Quercus grisca, Q. undulata), and pinyon (Pinus edulis).

"In the canyons and on steeper north slopes may be found heavy growths of gracilliformis, with which there occur locally Arizona cypress (Cypresses arizonica), Douglas spruce (Pseudotsuga mucronata), Madonna (Arbutus xalapensis), plum (Prunus virens) and others. The forests thus formed are quite dense, and the grasses are of the less xeric types. Spear grass (Stipa tenuissima), brome grass (Bromus marginatus), blue grass (Poa involuta), panic grasses (Panicum bulbosum), Oryzopsis fimbriata, and Muhlenbergia pauciflora are the principal ones.

"On one northeast slope there is an almost pure stand of Arizona cypress covering the upper 1500 feet (that is to say, from 6000 to 7500 feet) so conspicuously as to have caused the canyon to be "

Xeric is an ecologic term meaning adapted to growth under arid conditions.

20

named 'Juniper Canyon.' Intermingled with Cupresses are Quercus grisea, Q. undulata, and Q. canbyi var. chisosensis. Acer grandidentatum and Pseudotsuga mucronata are added as the slope face swings to the northwest.

"In another high canyon there is a west slope bearing a heavy growth of western yellow pine (Pinus brachyptera) with which are found western redbud (Cercis reniformis) and the aforemen- tioned oaks and junipers."

Flowering shrubs and herbs are seasonally showy and abundant. Red, deep orange, blues and purples are, in the aggregate, dominant over yellows. Prominently represented are the following families: spiderwort, rush, lily, Yucca, Amarylis, orchid, buckwheat, goosefoot, pigweed, four o'clock, pokeweed, purslane, chickweed, dewberry, poppy, mustard, Sedum, hydrangea, rose, mimosa, senna, pea, geranium, Oxalis, flax, caltrop, rue, milkwort, spurge, soap- berry, mallow, coachwhip, cactus, evening primrose, heath, primrose, dogbane, milkweed, morning-glory, Phlox, waterleaf, borage, Verbena, mint, nightshade, figwort, trumpet-creeper, unicorn, broom-rape, acanthus, madder, honeysuckle, Lobelia, ragweed and sunflower-the latter by a multitude of sorts.

Grasses, in addition to the dominants listed in the above quotation are abundant in kind and growth. Mueller lists 67 species as occurring at various localities in the Chisos. Several are common in adjacent Mexico but not known from other mountains in Texas. Of ferns and their allies, he lists 19 species, including the famous resurrection plant.

The mountainous regions, particularly the Chisos, Davis, and Guadalupe, have now been made easily accessible to motorists, with camping and hotel facilities. Texans particularly-especially those to whom this region is unfamiliar-should place it among the first in importance to be visited on the next vacation trip.

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THIS region, comprising roughly the territory reaching from the upper south Llano to the upper North Concho, might be called the south-central Edwards Plateau. It lies north of the rugged hills which characterize the Balcones Escarpment and south of the sandy south plains (11) and the Permian Redlands (13). Buffalo, curly mesquite and grama grasses together with adequate stock water, combine to make it an ideal ranching country. Streamways are heavily timbered with pecan, and the nuts constitute in themselves a very valuable crop. Other trees are western walnut, sycamore, hackberry, wild china, elm, and liveoak. The latter, in mottes, are a conspicuous landscape feature of the uplands. In the rougher, more hilly portions, Spanish oak and scrub (Mohr's) oak, shin oak and possibly some others, together with cedars, occur. Western redbud and Spanish buckeye are conspicuous when in bloom in early spring. In the more level and sandier portions, mesquite and species of Acacia are scattered over the grassland.

Intensive grazing, especially by sheep and goats, has greatly depleted the wealth of wild flowers which formerly covered the whole region in profusion. A few unpalatable sorts, like the pernicious, sheep-poisoning bitterweed (Hymenoxys odorata) are favored by overgrazing so long as an abundance of palatable food is available, but when scarcity of other forage forces sheep and goats to eat it, serious losses among the flocks result. At the present time one may drive over the whole region and hardly see any flower but bitterweed, except in areas protected from sheep and goats. This is not, in the case of perennials, because they are exterminated, but rather because they are too closely cropped to be able to bloom. In all well kept pastures, in spring and after rains, the buffalo or curly mesquite grass simulates a green velvety carpet dotted with liveoak and stretching out of sight over the undulating hills. Families of flowers naturally represented are many and varied, as well as colorful. This is abundantly shown in such areas as are protected from sheep and goats. An enumeration would be more burdensome than profitable, hence the interested reader is referred to the list of genera in the second part of this section.

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PERHAPS on the principle of first impressions being the most lasting, the image which comes most vividly to mind upon the mention of Trans-Pecos for those who know the country, is one of roughly rolling, high and rocky hills covered with a dense growth of sotol and lechuguilla; for this is what one beholds for miles from Del Rio to the Pecos and beyond. But these plants neither dominate the region indicated as 10 on the map, nor are they by any means absent from the mountainous regions-designated as 8-which rise above the general altitude to form the various ranges. In fact they are as prominent a vegetation type on the lower, sloping, mountain ridges as they are on the foothills and sub-foothills leading up to the mountains.

Northward, and mostly beyond the Pecos, mesas rise conspicuously above the intervening valleys. Their flat tops, formed by weather-resistant fragments of the Plains caprock, frequently overhang the softer underlying strata; and around the edges cacti, Acacia, Mimosa, Fouguiera, Condalia, and other thorny shrubs abound. Sotol and lechuguilla cover the slopes in many places. Intervening broad level "valleys" are covered with semi-desert grasses--burro, squirrel-tail, Muhlenberg, tobosa, and galleta, with buffalo, curly mesquite and the gramas in the better watered portions near streamways-and scattered xeric shrubs; or, on gravelly clay and somewhat saline soils, a mixture of creosote bush and Flourensia (a yellow composite) makes a conspicuous shrubby cover.

The latter type of vegetation is common also in foothills and broad inter-mountain valleys northward and westward to Utah and Arizona.

Over great stretches of country from the Pecos river to Sanderson the characteristic vegetation is the famous purple sage Cenizo (Leucophyllum texanum), a gray-leaved shrub which bursts into "

Xeric, implies adaptation to a dry habitat.

23

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a profusion of rose-colored bloom any, and every time, from spring to fall, that sufficient rain comes to give it the requisite water.

The most valuable range grasses are by all odds the various species of grama. These abound as a ground cover over most of the region whether valley or hill or mountain slope, and in normal years furnish an abundant range; but during periods of drought overgrazing is heavy.

Wild flowers show a periodicity in season induced by the semi-desert climate. Sorts which in a more moist region bloom in spring, here bloom whenever they can get the necessary moisture. This usually means they wait till mid-summer or early fall. Then, with plenty of rain, they cover all protected areas with a profusion of infinitely varied color. Showy species of four o'clocks, milkweeds, Asters, Senecios, milkworts, mallows, lupines, Astragalus, prairie clover, and many others are abundant.

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As the title indicates, this region is characterized by deep sand. Under the force of strong winds the sand has been piled into dunes, most of which have become stabilized by vegetation. Some, however, are still sufficiently bare to permit the wind to blow the loose sand. These are blowing dunes. Even on stabilized areas, railway and highway rights-of-way have to be protected against wind action in order to prevent burial of track or pavement.

Shallow basins occur from which there are no drainage outlets. Rain comes comparatively seldom; but, when it does come, in a large percentage of cases it comes in deluge proportions. Run-off from the slopes collects in the depressions, bringing along a solution of the alkaline salts with which the soil is impregnated. Recurrent evaporation through the years has produced the famous salt lakes, which under normal conditions have a shallow, concentrated liquid center surrounded by a bordering zone of crusted, snowy white, precipitated salts. Outside this zone the first vegetation appears in the form of fleshy leaved, succulent herbs, salt grass and salt cedar. On the adjacent slopes salinity rapidly decreases and vegetation assumes the character normal to sandy soil in a semi-arid, south-temperate climate. Drop-seed grasses, Mullenbergias, triple-awn grass, squirrel-tail, burro grass and tobosa are more or less intermixed with the more nutritious bluestems (Andropogon spp.) and gramas. Buffalo and curly mesquite grass are confined to tighter, finer textured soils; hence, are rare in this region.

Wild flowers are plentiful when rains give them a chance to grow. Mustards, morning-glory, borage, four o'clocks, western jimson-weed, fox-gloves and a wealth of blue, white, and yellow composites combine to give the landscape in bloom a gala array of color.

Upland shrubs are principally mimosas, acacias, mesquites, and, in certain areas, vast stretches of Havard's midget oak (Quercus havardii). The last named, on level or gently undulating areas, is frequently dense in stand and intermixed with little bluestem and   

26

saccharine bluestem, both of which overtop the oaks. This spectacle of a full grown oak "forest" bearing a wealth of grotesquely large acorns for such pigmy trees, and the whole overtopped by the tall bunch-grasses, is unique and botanically very attractive. It represents the best results nature has been able to attain in her effort to grow an oak forest upon a soil which to the highest degree conserves the scant rainfall it receives, when the above-ground portions of the vegetation are subjected to the terrifically evaporative effects of a very hot, dry and continuously windy atmosphere. Proponents of the shelter-belt project would do well to make a careful study of nature's achievement here before they set seriously about reviving their project on the tighter, more level, less conservative and more windswept high plains which constitute Region 12.

That is, moisture-retaining, referring to the capacity of the soil and sub-soil to hold quantities of water sufficient for plant requirements.

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THIS region is characterized by an apparently perfectly level topography which, however, has an imperceptible slope to the south, and by a compact, finely textured dark-colored soil underlain at a depth of a few feet by a weather-resistant, naturally cemented stratum known as caprock. Erosion. by streams has cut through this stratum and through hundreds of feet of the softer soil beneath, creating the beautiful canyons that, besides the sinkhole lakes described below, constitute the only break in the otherwise utterly monotonous plain. Sometimes narrow, sometimes wide, with the cliffs which enclose their sinuous main and lateral branches always topped by the jagged, precipitous or over-hanging ledge of caprock, these canyons are surpassingly beautiful, with or without vegetational adornment. In this striking physical setting a number of factors combine to bring about an infinite variety of conditions which reflects itself in an equally infinite variety in the appearance of the vegetational covering. Such factors are the presence or absence of seepage water; the widely varying degrees and directions of slope-exposure combinations, with their concomitant favorable or unfavorable effect on vegetational growth; and the occurrence of protected, well-watered canyon heads or pockets.

The virgin cover of the level plains was originally composed of buffalo grass and various grama grasses, with Smith's Agropyron occupying the gentle slopes which border the sink-hole lakes. These, as the name indicates, are ponds of run-off water collected at the bottoms of shallow, basin-like depressions from which there is no outlet. Soil in this region has in general little or no alkali salts. The result is that the water in the lakes is fresh and entirely suitable for stock; there is no concentration of salts in the surrounding soil; and the consequent vegetation is not of the succulent type characteristic of saline localities. Slopes offer some protection against wind-sweep and give some opportunity for out-seep of soil water, so that growth conditions are more favorable on the basin sides than on level stretches. Colonel Goodnight told me that, in the   

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early days, he had seen Smith's Agropyron as thick and tall as wheat covering thousands of acres of basin soil, and that it was common practice in those days to cut it for hay to tide over the winter. The more pervious and water- conservative of the soils of the uplands also supported good growths of the same grass-a perennial, stoloniferous, coarse, sod-forming species.

Below the caprock the steep slopes connecting with the lands below, whether with the canyon floor or with the surrounding eroded plain, are covered with scant timber, of which cedar is the most common dominant, growing in open stand upon grassland. Along permanent water courses cottonwoods are common on the wide, open canyon floors; while scrubby hackberry, elm, willow, wild china and plum increase in size and height in proportion as the narrowing canyon gives greater protection from the sweep of drying winds, and as soil water becomes more abundant. In places embodying unusually favorable conditions, sizable trees are not uncommon.

Grasses are in the main the same as are found on the level upland; but the aspect is changed by the addition of other species, such as Stipa meo-mexicana, S. spartea, Muhlenbergias, triple-awn and other grasses. Colorful wild flowers are Astragalus and many other legumes, buckwheat allies, spiderworts, wild onions, docks, evening primroses of great variety and profusion, four o'clocks, mustards, borages, scrophs and a wealth of composites of every shade, hue and size.

Clinging to the ledge of caprock and about the precipitous sides of steepest canyon walls are shrubs of Condalia, Ephedra, Yucca, Nolina, Havard's oak, plum, Acacias, Mimosa, and mesquite. Grape, Smilax, Clematis, moonseed and perhaps Cissus and Ampelopsis are not uncommon vines in moist shaded situations.

The region as a whole is very fertile and rainfall is high enough in wet years to produce good crops of wheat, grain sorghums, and cotton; while the use of machinery in cultivation and harvesting greatly increases the acreage an individual can tend. The result is that the region has been transformed within the past quarter-century from a cattle country to an agricultural region. Dry-land "

Water-retaining.

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farming methods necessitate early fall breaking in order to prepare the land to receive and store as much as possible of the hoped-for fall and winter rains. During periods of drought these rains fail wholly or in part to materialize, in their stead appearing sweeping dry northers which pick up the loose soil, filling the atmosphere with a choking cloud of dust which is spread southward, some of it far out over the Gulf of Mexico. The winters of 1933-34, 1934-35, and 1935-36 particularly the second, saw a dry phase of the weather cycle during which the soil of ploughed ground was blown away down to the shear-plane of the plow point; and the region became popularly known as the "Dust Bowl." Restoration of its native buffalo- and grama-grass cover seems the only logical hope of preventing disastrous recurrences of these dust storms; continued cultivation seems certainly to assure such recurrences.

Thornthwaite, C. W., 1936, "The Great Plains," in "Migration and Economic Opportunity," University of Pennsylvania Press, Chap. 5, pp. 202- 250, 11 figs., 1 pl.

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THIS region, while including within its bounds a great variety of topography and soil, each type with its own peculiar vegetational landscape, may be properly designated as characterized in general and upon the smoother portions by an open stand of mesquite upon a rich grassland. Upon the rough, dissected portions, where bold hills-in part, remnants of the eroded Great Plains- stand in rugged resistance to nature's weathering, scrub oaks, cedars, Mimosas, Acacias, and other woody brush are prominent. Along Red River and its several tributaries and forks, great sand dunes are shifted back and forth at the whim of changeful but predominantly southeasterly winds. Other sandy stretches, notably in Taylor and Fisher counties, mark the westernmost limit of distribution of the Post-oak. But the most outstanding and widespread characteristic of this region, before agriculture devoted the rich Permian Redbeds to crops, was the open mesquite savanna which constituted the virgin vegetation on this important geologic formation. Other thorny brush, as Condalia, Zizyphus, Mimosa, and Acacia occur in this region, but the great natural woody dominant is mesquite.

The grassland is largely composed of buffalo, various gramas, purple triple-awn, and fox-tail grasses. In the more moist situations and on the rougher stony outcrops, little bluestem, Triodias, and other bunch grasses are found. Wild flowers are plentiful and varied, being on the whole much the same as are present along the breaks and canyons of the High Plains.

Small grain is grown in the northwestern portion on such lands as are favorable to agriculture, while throughout the region agricultural lands are well adapted to cotton and to the grain sorghums. Most of the soils of the Permian contain enough flocculating material to render the soil at once quite porous and pervious to moisture and yet to cause it to withstand blowing. The region contains some of the finest dry-farming lands of the state, while the rougher, untillable portions are devoted to grazing.

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REGIONS 14 and 15 are strips of woodland stretching across grassland, hence the term "Cross Timbers." Both occupy sandy soil, to which they are confined. Regions 14, 15, and 16 are similar to each other in that they have the same woody dominants; namely, postoak, blackjack, and in some localities, hickory. The last is wanting in many places, as is sometimes also blackjack. Occasionally both may be present, with little or no postoak. The most abundant and widespread member, however, is postoak. In fact it is spattered out, as it were, westward and southward over regions 13, 9, 6, and 7 in those scattered localities where sandy or gravelly soil, with the right admixture of subsoil clay and sand to make a good water reservoir, occurs covered by sandy top soil adapted to a high degree of absorption in time of rain and of protection against surface evaporation in time of drouth. Such a soil is the best possible conservator of moderate or scant precipitation. Postoak and blackjack are well adapted to moderate supplies of water and, hence, are found on such soils farther west than any other trees of the eastern coastal plains forest. Always they are found on sandy or gravelly soil with a reddish clay and sand sub-soil. In Taylor and Fisher counties, as outlined below (Region 15), the westernmost representatives of this type of woody vegetation are found on deep sand. In some portions the stand of timber is open, in others it is close and thickety. In locations within the region where limestone outcrops occur, liveoak is usually found. Conversely, throughout Region 18, wherever sandy or gravelly outcrops or deposits occur, postoak is always found. Along the sinuous line of contact between woodland and prairie, mottes of timber near the edge of the prairie are the rule.

Of recent years a decided invasion by Virginia cedar has produced a noticeable scattering of this evergreen through much of the oak-hickory forest. Apparently the cedar wax-wing and other small birds plant the seeds under the oaks. An undergrowth of brushy   

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wooded regions in many localities from Region 16 westward. Yaupon, crooked bush, agarita, Mexican cedar and other sorts are all common, the last two being confined mostly to limestone soils. Grasses prominent in all the oak-hickory regions are: triple-awn, crab-an especially vicious weed in cultivated fields-Triodia, bluestems, bromes, gramas, and buffalo on tighter alkaline soils, bur-grass, sprangle-top, needle-grass, panics, hurrah, love-grass, dropseed, Bermuda and some Johnson grass. A wide variety of sedges also occurs, especially in damper situations, as in wet weather ponds and around their edges. Families of wild flowers are much the same as those found in other regions, but in many places having specific representatives, which give a characteristically different appearance to the landscape in blossom. Nuttall's chickweed, pilose and slender Phlox, lance-leaved and deep red Gaillardia, red paint-brush, cottony Froelichia, umbrellawort, daisies, bitterweed (Helenium spp.) goat weed (Croton spp.) and many others contribute their specific bits to the general oak-hickory wild-flower landscape.

The regions are all well adapted to corn and cotton and to such truck crops as peas, peanuts, tomatoes, sweet potatoes, sorghum, watermelons and others. The land is not as productive of the staple field crops as is that of regions 7, 12, 13, and 18; but it makes up, in a measure, by being much more productive of those crops which enable a farmer to "live at home."

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THIS region occupies a sandy stratum known as the Woodbine Sand, which lies at the base of the Upper Cretaceous group of rock beds and outcrops substantially as indicated on the map (Plate 1). The woody dominants are essentially the same in regions 14 and 15, with the Eastern Cross Timbers having the advantage of several more inches of average rainfall per year. This tends to produce somewhat larger timber here, on the average, than is found in the Western Cross Timbers. A timbered strip of sandy soil bordering Red River-except for a short gap in northern Cooke County where the prairie touches the river-connects regions 14 and 15 with each other and with region 16. Practically the same grasses and showy wild-flowers are common to both these timbered strips and also to region 16.

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THE line delimiting the western margin of this region and the eastern margin of Region 18 is the line of contact between outcropping Navarro and Midway geological formations.' The former is a marl, a limy (calcareous) clay; the latter a mixture of sand and clay, the clay red or yellow, or of some other color. As usual, the actual line of contact between the two regions is exceedingly sinuous with mottes of timber standing as islands in the prairie and with embayments of prairie lying both between peninsular timber strips and as "lakes" well within the timbered region wherever marl deposits become locally of sufficient thickness materially to diminish the absorption and increase the surface evaporation rate of the soil. Such grassland inclusions in the Oak-Hickory Forest were prized by pioneers because of their higher fertility and because of the fact that it was unnecessary to clear away timber and cultivate stumpy "new ground" for several years before a cleared field became really profitable. Community names throughout the region still commemorate the occurrence of these virgin bits of prairie. Roark's Prairie, Crabb's Prairie, Pine Prairie, Cline's Prairie, Round Prairie, and others in my home county of Walker are examples that can be duplicated in any other county of the region. Some such prairie fragments are found even in Region 17. In fact a part of those enumerated lie within that region, the line separating 16 and 17 passing through Walker County.

That portion of the region lying southwest of the Brazos River is somewhat unique in that it contains two plants of outstanding interest: the official Texas state flower (Lupines sub-carnosus) and Drummond's Phlox (Phlox drummondii). The fact that Lupinus sub-carnosus is the State Flower rather than the more showy and more widely distributed Lupinus texensis, seems to be due to an inadvertant error on the part of those sponsoring the Bluebonnet. In drawing up the joint resolution designating an official flower, the committee specified sub-carnosus, thinking, doubtless, that texensis   

36

was included. They are quite distinct species, however, and hence texensis is not the state flower.

Drummond's Phlox, rated the most loved of all garden annuals and cultivated in every civilized country on earth, is native of the same region and not known to be native elsewhere, at least not with the beautiful shade of deep red which charactrized the plant upon which the original description and the colored illustration accompanying it were based some hundred years ago. Seeds sent to England by Drummond were planted, the species figured and described, and the plant widely introduced into gardens by the Botanical Garden at Edinburgh. It thrived in cultivation, grew in favor, produced a prodigious number of varieties, and has, within the short space of a century, attained first place among cultivated garden annuals. Its behavior, both wild and under culture, has led many to believe that hybridity was involved in the original collection of seeds and that the immense number (150 or more) of varieties has been produced by the segregation of sets of heritable unit characters. (See frontispiece.)

Also south of the Brazos, the region is cleft by the Fayette Prairie. Again, marl of limestone origin and with a very fine texture, highly colloidal in nature, is correlated with the vegetational cover of the cleavage grassland (Region 3). The lower fork of Region 16, characterized by diminishing height and increasingly open stand of the postoaks, reaches the vicinity of Sinton in San Patricia County. Its line of contact with the Pine-Oak Forest constituting Region 17 will be discussed in connection with that region.

In the general, the vegetation and agricultural adaptations of the region are very similar to those of the preceding two. Rainfall continues to increase eastward and is reflected in a taller and denser stand of timber; but, otherwise, the differences are too slight to warrant any attempt at description within our limited space.

Colloidal. This term means that the individual particles are so fine as to cause a wet mass rubbed between the fingers to appear smooth-textured and gelatinous. This fineness of texture prevents the particles from existing as separate granules (as in sands); it causes them when dry rather to adhere tightly together in aggregate clumps ranging in size from flocculate crumbs to hard clods.

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THIS region is characterized by the large number of species of trees of which its forest is composed. Especially is this true of the oaks and hickories, both in the bottoms and on the uplands. Maple, sweetgum (the red gum of lumbermen) black-gum, Magnolia, birch, cottonwood, elm, walnut, linden, willow and other trees are common. On sandy uplands sweetgum is frequently co-dominant with short-leaf or loblolly pine. There, its straight trunks-covered with branches which bear bright glossy green leaves turning red in the fall-are fully as tall as those of the pines. In the bottoms, crowded among other lofty forest hardwoods, its trunks are self pruned and branchless for 30 to 50 feet, making excellent lumber for cabinets and finishing work. So different in growth habit are they from the upland type that many lumbermen look upon them as entirely distinct.

Under the canopy of taller trees, or in the open pine forest, are fringe tree, red- and black-haw, huckleberry, persimmon, Sassafras, redbud, dogwood, holly and other small, showy, flowering trees. Creek and river bottoms contain ironwood, hop-horn-bean, planer tree and mulberry. Common upland shrubs are French mulberry, wax myrtle, partridge berry and, in dense stands of pine, subdued blackjack and postoak of dwarf stature. Some of the latter, small trees of 2 or 3 inches diameter, contain 40 to 50 annual growth rings. Bottomlands are in many places on the open floor of the forest densely covered by dwarf palmetto.

Hickories range from Buckley's hickory on the uplands to the water bitternut in the bottoms along sloughs. Buckley's hickory continues in many localities as a co-dominant on the uplands. Oaks tend to occupy the tighter upland soils and the bottoms. Postoak, red oak, black-jack, blue- or sand-jack, water oak, willow oak, yellow oak, basket oak and white oak are common in various situations. The first three share dominance on the tighter uplands as indicated, pine, sweetgum and hickory being more nearly restricted to sandy   

38

soil. The whole region is more in the nature of a mosaic than an even mixture of the several dominants within the same stand.

Attractive herbaceous wild-flowers are found throughout the region and almost throughout the year. In late January bluets, violets, mustards, spring beauty, and Micrantha appear, to be followed by daisies of various kinds, jack-in-the-pulpit, orchids, Iris, arrowheads, pickerel-weed, yellow-eyed grass, pipeworts, Spanish moss, day flower, spiderwort, lilies, wild onion, amaryllids, Iris, Canna, Burmannia, lizard's tail, birthworts, chenopods, pigweeds, umbrellaworts, carpetweed, water lilies, buttercup, Corydalis, poppies, roses, beans and peas in great variety, sennas, spurges, mallows, St. John's wort, passion flowers, loosestrifes, meadow beauties, evening primroses, wild carrots of great variety, dogbanes, milkweeds, morning-glories, Phlox, waterleafs, borages, verbenas, mints, nightshades, figworts, bladderworts, acanthaceous relatives, plantains, madders, valerians, cucurbits, lobelias, ragweeds, thistles, thoroughworts, Asters and relatives, sunflowers and relatives, bitterweed and relatives, dog fennel and relatives and dandelion and relatives.

Spring and fall are the two most showy seasons, with summer, especially during dry seasons, much less so.

Reference to the distribution map shows a fragment of this region separated from the main portion by a considerable strip of oak-hickory. This fragment is located mostly in Bastrop County. Other fragments not represented on the map are found in Lee and Caldwell counties. They are thought to be relict remains of a once much more extensive forest which existed when the humid area extended much farther westward than at present. With the decrease of rainfall, pine was forced to withdraw eastward to the present western boundary of Region 17, except for these few small stands, which, occupying soil unusually adapted to them, were enabled to maintain themselves.

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THIS prairie, in Texas, occupies clay and silt soils containing much calcium carbonate disseminated throughout. That of the northern portion extends westward to cover a part of the lower as well as the Upper Cretaceous, the two being separated by the Woodbine Sand whose outcrop supports the Eastern cross-timbers.

Reference to the vegetation map (Plate I.) shows this region to begin at a point below San Antonio and extend northeastward as a gradually widening strip which above Waco broadens out greatly and is cleft by the Eastern Cross Timbers, growing, as above indicated, upon the outcrop of the Woodbine Sand. That portion lying west of the timbered strip is supported by the rolling hills of the Lower Cretaceous, that lying east, by the marly clays of the Upper Cretaceous.

The eastern or "black waxy" prairie extends into a rainfall region of 40 inches; the western into a region of 30 inches or less. Decreasing rainfall has a marked selective effect upon the species which comprise the plant population. Eastward, the dominants are of the tall bunch grass type; westward, these tend to give way to grasses of lower stature. Big and little bluestem, dropseed and needle-grass are representative dominants eastward; gramas, Triodia and buffalo grass increasingly so westward.

Included within both regions are occasional rough stony outcrops covered with cacti, Condalia and other thorny scrub. Local sand and gravel deposits support a growth of postoak. Mesquite is quite common in the whole region; less so in its northeastern portion than elsewhere. It covers some of the marly eastern portion, and also deep soiled, level areas in the western portion with a more or less dense stand of scrub timber, frequently admixed with prickly pear.

Being highly adapted to agriculture, the region is almost wholly under cultivation except in the extreme northwest where rainfall is insufficient. Such land as is untillable is devoted to pasture and usually greatly over-grazed. A few native hay meadows have been   

40

preserved and constitute accurate representations of the composition of the original prairie vegetation as the pioneer first saw it.

Wild flowers, because of the conditions above suggested, are greatly depleted as compared with their abundance under virgin conditions. Among them are: day flower, spiderwort, rushes, wild onion, crow-poison, wild hyacinth, rain lily, irids, pigweeds, four o'clocks, umbrellaworts, chickweeds, sleepy catchfly, water lilies, Corydalis, mustards, dewberries, sensitive briar, Acuan, Neptunia, senna, Krameria, Amorpha, bur clover, ground plum, prairie clover, Psoralea, milk pea, Oxalis, flax, milkwort, Croton, Ditaxis, spurge nettle, princess spurge, many milk spurges, balloon vine, mallows, green violets, cacti, loose-strifes, evening-primroses, carrot relatives, milkweeds of many kinds, morning-glories (tie-vines), Phlox, borages, vervains, mints and sages, nightshades, figworts, Acanthus relatives, plantains, madders, honeysuckle, Valerianella, cucurbits, rag-weeds, cockleburrs, ironweeds, thoroughworts, Asters, everlasting, sunflowers, bitterweed relatives, squaw weeds, thistles, and dandelion relatives.

41

• Adder's Tongue (Ophioglossum) ; 1, 6, 7, 13, 14, 15, 16, 17.
• Royal Fern (Osmunda regalis) ; 1, 16, 17.
• Cinnamon Fern (Osmunda cinnamomea); 1, 16, 17.
• Polypody (Polypodium spp. ); 1, 7, 16, 17.
• Cliff Brake (Pellaea spp.); 4, 6, 7, 8, 9, 10, 12, 13.
• Bracken (Pteridium sp.); 1, 16, 17.
• Maidenhair (Adiantum) ; 6, 7, 8, 9, 10, 12, 13.
• Lip Fern (Cheilanthes) ; widespread except in 11, 13, 14, 18.
• Lorinseria; 1, 16, 17.
• Notholaena spp.; 6, 7, 8, 9, 10, 12.
• Anchistia; 1, 16, 17.
• Spleenwort (Asplenium spp.); widespread except in 11, 13, 14, 18.
• Christmas Fern (Polystichum) ; 1, 16, 17.
• Shield Fern (Dryopteris spp.); 1, 16, 17.
• Woodsia; 1, 16, 17.
• Four-leaf-clover Fern (Marsilea spp.); widespread in ditches and along seeps.
• Water Fern (Azolla); 1, 7, 16, 17.
• Horsetail (Equisetum. spp.); 1, 7, 8, 12, 13, 16, 17.
• Ground-pine (Lycopodium spp.); 1, 2, 17.
• Selaginella (including the resurrection plant in 8, 10); 1, 6, 7, 8, 9, 10, 16, 17.

Species too numerous to mention.

42

• Pine Family: PINACEAE
  • Pines (Pinus spp.)
    • Long Leaf (P. palustris) ; 1.
    • Short-leaf (P. enchinata); 1, 17.
    • Loblolly (P. taeda); 1, 2, 17.
    • Pinon (P. edulis); 7 8, 9, 10.
    • Western Yellow (P. brachyptera); 8.
  • Spruce (Pseudotsuga taxifolia); 8 (chisos).
  • Cypress, Bald (Taxodium); 1, 2,`.2. 9, 17.
  • Cypress, Arizona (Cupressus); 8 (Chisos).
  • Cedar (Juniperus spp.); more or less present in almost all regions except 1, 4, 5; but they are particularly abundant in 6, 7, 8, 9, 10, 11, 12, 13, 14, and scattered locally in 15, 16, 17, 18. For a systematic treatment see Sargent: Manual of the Trees of North America.
• Joint-fir Family: GNETACEAE.
  • Ephedra spp.; 4, 6, 7, 8, 10, 11, 12, 13.
• Cat-tail Family: TYPHACEAE.
  • Typha spp.; in marshy open situations in all areas.
• Pond-weed Family: ZANNICHELLIACEAE.
  • Pond-weeds (Potamogeton spp.); in open fresh or slightly brackish water in all regions.
  • Sea-grass (Ruppia maritima); in quiet shallow protected sea water along the whole coast.
  • Horned Pondweed (Zannichellia palustris); in quiet fresh water, all regions.
  • Eel-grass (Zostera marina); in brackish water or sea water along the coast.
• Water-nymph Family: NAIADACEAE.
  • Water-nymph (Naias spp.); fresh or brackish water, along the coast and inland.
• Water Plantain Family: ALISMACEAE.
  • Water Plantain (Alisma sub-cordatum); fresh water marshes and in shallow water, supposedly widespread, but represented by few collections.
  • Water Plantain, Dwarf (Helianthium); shallow fresh water along the coast.
  • Bur-head (Echinodorus spp.); marshes and shallow water, along the coast and in the interior.
   

   

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  • Lophotocarpus spp.; marshes and in shallow water along the coast and inland.
  • Arrow-head (Sagittaria spp.); widespread in mud or in shallow or deep clear water; fruiting entirely submerged in the lake at San Marcos.
• Grass Family: GRAMINEAE. Grasses: for a detailed treatment of the species of grasses found in Texas, the reader is referred to Texas Grasses by W. A. Silveus, published by the author at San Antonio, 1933; and to A Manual of Grasses of the U. S. by A. S. Hitchcock, published by the U.S.D.A. 1935 and obtainable from the Superintendent of Documents, Washington, D. C. Some of the most important groups are suggested in the following list and are mentioned in connection with the flora characteristic of the several regions appearing on the accompanying map (Plate I.).
  • Brome grasses (Bromus spp.); especially B. unioloides, furnish green winter forage of some value in eastern and central Texas (Regions 3, 7, 16, 18).
  • Blue Grasses (Poa spp.) are of little grazing importance. P. annua is a winter annual of some slight value, but is little more than a weed.
  • Blue-stem (Andropogon spp.) are widely distributed. Particularly is this true of A. scoparius and A. saccharoides. While many of the 23 or 24 species and varieties which occur have definite palatability and nutritive value, none can withstand intensive grazing. Nearly all virtually disappear within a few years from heavily grazed pastures.
  • Triple-awn Grasses (Aristida spp.) are unpalatable and lacking in nutritive value. They are coarse, wiry, weedy grasses that flourish on poor soil and in worn-out fields. Their unattractiveness to stock enables them in many instances to become dominant in over-grazed pastures all over the state.
  • Georgia cane (Arundo donax) grows abundantly in marshes near the mouths of rivers along the coast, and is also of some value in stopping erosion when planted along washes in fields (18). It has little if any forage value.
  • Fishing-pole Cane (Arundinaria spp.) occurs in the river bottoms of eastern Texas (1, 16, 17). It has considerable value as winter browse when it occurs in dense stand.
  • Carpet-grass (Axonopus compressus) is an exceedingly valuable pasture grass in 1, 2, and 17. It is palatable and nutritious, and withstands grazing superbly. Near the coast it is practically evergreen.
  • Grama-grasses (Bouteloua spp.) are represented by a dozen species of which more than half are valuable range grasses. Except in regions 1, 5, 14, 15, 16, 17 they are of sufficient abundance to be of great importance particularly from 2, 3, and 18 northward. Collectively they rank equally with Buffalo grass in grazing importance within the state as a whole.
  • Buffalo Grass (Bulbilis dactyloides) shares first rank with the Grama grasses in grazing value. It ranges from 3 and 18 northwestward to   

   

  44

  Canada. It is not abundant in Texas west of the Pecos, however (8, 10).
  • Bur-grass: Sand Burr (Cenchrus spp.); in sandy soil, particularly in central and eastern Texas, the grass bur is abundant. While young it is palatable, but its vicious burs cause stock to reject it after it starts to fruit.
  • Colorado Grass (Panicum texanum); a coarse weedy grass abundant in the sandy fields of the valley of the Colorado River, is of some considerable value both for fall grazing and for hay.
  • Crab-grass (Digitaria sanguinalis) is the most pestiferous weed of the sandy land fields of 1, 15, 16 and 17. Though relished greatly by stock, it is very difficult to eradicate from among growing crops, and in wet years it frequently chokes out such crops entirely.
  • Curly Mesquite (Hilaria belangeri) extends from regions 2, 7, 9 and 10 southward into semi-arid eastern Mexico. It is almost on a par with the Gramas and with Buffalo grass wherever it occurs in dense stand, notably in regions 7 and 9. It greatly resembles Buffalo grass from which it is difficult to distinguish when not in fruit.
  • Galleta Grass (Hilaria jamesii) is one of the toughest grasses found in the state. It occurs in the driest portions of regions 9, 10, 12 and 13. Its dry nutritionless tufts stand for years, preventing stock from availing themselves of the small satisfaction they might otherwise find in the new growth induced by seasonal rains.
  • Tobosa (Hilaria mutica) is very similar to galleta (q.v.) but still tougher and less palatable.
  • Gama (Tripsacum dactyloides) occurs as an important constituent of the eastern portion of region 2 and occasionally along low moist soil northward and westward through 7 and 14.
  • June Grass (Koeleria cristata) occurs in the northeastern prong of 18, and in the high moist valleys of mountains 8. Increasing aridity and heat prevent its occurrence on the intervening regions.
  • Sprangle-top (Leptochloa) in one or more species occurs in most vegetational regions of the state, but it is seldom important as a grazing constituent.
  • Muhlenberg's Grasses (Muhlenbergia spp.) occur in increasing importance from 4 and 18 westward and northward. Nowhere, however, can they be classed as a real dominant, despite the fact that like many other genera they are represented by a goodly number of species.
  • Needle Grasses (Stipa spp.) are found in practically all regions except perhaps 10 and 11. S. leucotricha is an important constituent of the grasslands in 3, 7, 9, 13, and 18.
  • Panic grasses (Panicum spp.) are the largest group in any one genus, being accredited with no less than 85 species in Texas. Though an interesting group, they are of comparatively little economic significance, except Colorado grass, Grapevine Mesquite (which see) and P. virgatum, a tall, rank bunch grass contributing substantially to prairie hay in the moist lowlands of 1, 2, 3, 16 and 17.
   

   

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  • Grapevine Mesquite (Panicum obtusum) occurs as a coarse sod-former in low moist localities of 3, 7, 8, 13 and 18. The name comes from its habit of putting out, in wet weather, long stolons (up to 10 ft.). It roots at the nodes and is able to withstand considerable grazing which gives it local prestige among stockmen.
  • Salt grass; medium (Distichlis spicata) is a turf producing perennial with fruiting stems rising to 12 or 18 inches above the prostrate turf stems. It is found in very saline situations both along the coast and inland (10, 11, 13). Other Salt Grasses (see below, p. 46).
  • Hurrah grass (Paspalum spp.); in general tends to flourish in moist, low situations. Accordingly various species are important constituents both as grazing components and as weeds in such situations through, out regions 1, 2, 3, 7, 14, 15, 16, 17, and 18. Space precludes any detailed enumeration. They add materially to prairie hay in 2, 3, and 18.
  • Giant Reed (Phragmites communis) is abundant in fresh or slightly brackish marshes or shallow water along the coast and inland; 1, 2, 3, 16, 17. Along the lower Sabine and Neches rivers great areas of marsh are dominated by this tall grass.
  • Squirrel Tail (Sitanion hystrix) is frequently a conspicuous landscape feature when in head; in regions 9, 10, 11, 12. It somewhat resembles a low bushy Elymus, or a densely flowered triple-awn grass. While very ornamental it is of small grazing value except where young growth is just coming from burned-over lands in the spring or summer.
  • Fescue (Festuca) is represented by several unimportant species.
  • Love Grass (Eragrostis) represented by one or more species, occurs as a grass constituent in all regions. While frequently palatable, its sparseness relegates it to secondary or less importance, despite the fact that the number of Texas species is relatively large (upward of 30).
  • Dune Grasses:
    • 1. Sea Oats (Uniola paniculata) occurs mostly along young, growing, insular dunes from Matagorda peninsula southward. It seldom occurs on the mainland. Coarse rhizomes and an abundance of tough matted roots enable it to bind sand which blows into its clumps, and make it an important pioneer in dune building.
    • 2. Hall's Bluestem (Andropogon hallii) performs much the same function along Red River (13). It has also been found on the mainland dunes at Flour Bluff below Corpus Christi.
    • 3. Blue-stems (Andropogon spp.); Big, Little and/or others are found on stabilized dunes in all situations where dunes are found.
  • Dropseeds (Sporobolus spp.) are of some importance as grazing constituents in 2, 3, 7, 16, 18. Sporobolus virginicus is a coarse turf former resembling Distichlis on wet saline coastal flats; S. drummondii and allied species were substantial members of the original   

   

  46

  vegetation of 18; S. poiretti, smut-grass, is a tough perennial of 1, 2 and 17; S. cryptandrus is common in the sandy portions of 11, 13, 14, 15 and 16.
  • Salt grass, tall (Spartina spartinae); the sacahuiste of the coastal vaquero, is the most conspicuous grass along the immediate. Texas coast throughout that coast's extent. Growing in dense clumps sometimes three feet across, its stiff spine-tipped leaves deal misery to the legs as one makes his way through it. Though coarse and tough in age, it is tender and palatable when young. It also has the peculiar faculty of burning readily while still green; and one of the commonest sights in summer along the coast is the smoke from controlled prairie fires deliberately set for the purpose of burning out the old dry stems and producing young tender forage.
  • Salt grass, fine (Monanthochloa littoralis) resembles Bermuda in growth habit, but is substantially coarser. It is found in wet flat saline situations along the coast, and inland to Gonzales County (Pilgrim salt flats, 16). It is an important dominant locally as indicated, but it is too tough and salty to be of any value for grazing. Salt Grass, medium (see above, p. 45).
  • Bermuda (Cynodon dactylon); an introduced grass, is the most important pasture and lawn grass in the southeastern states. It extends into central Texas and is almost exclusively used for lawns over the whole state. In the western portions, and even in the black land of the eastern (18) it must be watered during the hot summer months. It is, however, the most pernicious weed known to fields in the sandy lands of regions 1, 16 and 17, thriving in loose, moist, sandy soil.
  • Triodia (Triodia spp.) is well represented by numerous species covering practically all regions; but as with several other genera, little forage importance is attached to any member of the group. T. pilosa in 7, 9, 13, 14 and 18 is a short tufted perennial which withstands grazing well, and which makes a substantial contribution to grazing value.
• Sedge Family: CYPERACEAE.
  Sedges are grass-like herbs, mostly weeds of little economic importance. A few (notably "nut grass") are pernicious pests, a few are palatable and nutritious to stock, and almost all are eaten at least indifferently. In loose sandy soil the hard corns or "nuts" of nut-grass are available to hogs-sometimes in paying quantities.
  In general Sedges are most abundant in moist sandy soil or in marshy situations. Not many occur in the dry uplands of the central and western regions.
  Few sedges carry common names and almost none are of sufficient importance to attract general attention or command general interest. Being neither conspicuous nor important, they will be given no more of the limited space allotted to this section.
 

 

47

• Palm Family: ARECACEAE.
  • Dwarf Palmetto (Sabal minor); conspicuous in the river bottoms of eastern Texas, extends to the Guadalupe River (2, 16, 18) and to the vicinity of Rockport.
  • Mexican Palm (Sabal Mexicana) occurs along the lower Rio Grande below Brownsville (notably in the famous Rabb Palm Grove) and is widely cultivated in that part of region 4.
• Jack-in-the-Pulpit Family: ARACEAE.
  • Jack-in-the-Pulpit (Arisaema) ; 1.
  • Green Dragon (Arisaema dracontium); 1, 2, 6, 7, 9, 16, 17.
  • Arrow-Arum (Peltandra); 1, 17.
  • Water-lettuce (Pistia); westward to 7.
  • Calamus (Acorus calamus); comes into 1, 17; marshy, shaded soil.
• Duckweed Family: LEMNACEAE. Widespread in almost all regions. The four genera representing the family (vis. Lemna, Wolffia, Wolffiella and Spirodela) all occcur abundantly in the lake at the head of the San Marcos River.
• Mayaca Family: MAYACACEAE. A single collection from near Athens (16) represents this family in the University of Texas herbarium.
• Yellow-eyed-grass Family: XYRIDACEAE.
  • Yellow-eyed grass (Xyris spp.); 1, 2, 16, 17. Especially abundant in wet woods, Region 1, and in marshes of the others indicated.
• Pipewort Family: ERIOCAULACEAE.
  • Pipewort (Eriocaulon); 1, 16, 17.
  • Pipewort (Lachnocaulon); 1.
• Pineapple Family: BROMELIACEAE.
  • Ball Moss (Tillandsia recurvata) is common on oaks and mesquite in the uplands of 3, 4, 6, 7, 16, 18. It is commonly thought to be injurious to the host, though clearly shown to have no organic connection between its own living tissue and that of its support. Moreover it flourishes on frayed electric light wires, tombstones (both granite and marble) and occasionally on limestone, further demonstrating that it is no parasite. Bailey's Ball Moss (Tillandsia baileyi) occurs in Region 4. It is much larger than the former and has large, deep rose-colored flowers an inch across.
  • Spanish Moss (Tillandsia usneoides) is common in river bottoms and low woods in the vicinity of the coast (1, 2, 16, 17) where it hangs in long beautiful festoons from tree branches.
• Day-flower Family: COMMELINACEAE.
  • Day-flower (Commelina spp.) ; like the spiderwort, is widely distributed as several species.
  • Spiderworts (Tradescantia spp.) are in one species or another, widely distributed in almost all regions.
 

 

48

• Pickerel-weed Family: PONTEDERIACEAE.
  • Pickerel weed (Pontederia cordata) is common lining slow streams i n the shallow edges and along muddy banks in 1, a, 16, 17.
  • Water Hyacinth (Piaropus crassipes) is most common in slow bayous and canals in 1 and 2, where it frequently so chokes such water ways as to make boating very difficult. Accordingly, its exceeding beauty doesn't save it from its reputation among boatmen for being a veritable pest.
  • Water Star-grass (Heterantheraa spp.) is not uncommon in open water or in mud in regions as far north and west as 14 and 7.
• Rush Family: JUNCACEAE.
  • Rushes (Juncus spp.) are rich in species (two dozen or more). They are quite conspicuous in all marshy situations over the entire state, including both fresh and salt marshes. Juncoides occurs in moist woods, regions 1, 16 and 17.
• Lily Family: LILIACEAE.
  • Wild Onions (Allium spp.) occur in all regions. Their rose colored or white blooms feature almost every landscape during the early spring. An unusual yellow flowered one, Allium coryi, occurs in the vicinity of Alpine.
  • Crow Poison (Nothoscordium bivalve) is widespread. It is a white-flowered onion minus the onion odor. The name, as is frequently the case with common names, maligns the plant, which is neither poison nor eaten by crows.
  • Androstephium, a sweet scented delicate, pale, blue-flowered, onion-like plant 6 to 8 inches tall, blooms in early spring. The flowers are 2-6 in number, and about an inch across. Each bears in the center a tube (crown) similar to that in jonquils. Regions 3, 7, 14, 15, 16.
  • Lily, Carolina (Lilium, carolinianum) is the only species of true lily known to occur naturally in the state. It is found in rich moist soil, regions 1 and 17.
  • Dog's Tooth Violet (Erythronium albidum) occurs in rich moist soil in the northeastern portion of 18, and in adjacent portions of 15 and 16.
  • Wild Hyacinth (Quamasia hyacinthina) occurs in regions 3, 7, 16, 18. Its delicate, sweet-scented, steel blue flowers, each ¾-inch across, in a 3- to 6-inch raceme topping an 18-inch scape, dot the landscape locally in the regions indicated during early spring.
  • Yucca, in some of its various species, is common throughout the state. Yucca arkansana in regions 1, 7, 14, 15, 16, 17, 18; Yucca rupicola in regions 3, 4, 6, 7, 9, 13, 18; Yucca treculeana (Spanish Bayonet) in regions 4, 7, 9, 10, 12; Y. glauca in 7, 9, 10, 11, 12, 13; Y. elata in 9, 10, 12, are some of the more conspicuous features of the landscape in spring.
  • Bear-grass, Slender leaved; Sacahuiste to the Big Bend vacquero (Nolina spp.) is found in regions 6, 7, 8, 9, 10. Its long, narrow, tough leaves, growing in conspicuous bunches, frequently 6 feet in diameter,   

   

  49

  dot the open valley grasslands. Rejected by cattle when grass is good, it is eaten to stubs by the starving brutes during periods of excessive drought.
  • Sotol (Dasylirion, spp.) is a dominant landscape feature in Region 10, where its slender, pliable, but viciously hook-toothed leaves grow in dense clusters at the tops of low stems. It is found native also in regions 7 and 9, and perhaps in the northwestern portion of 4.
  • Wake-robin (Trillium lanceolatum) occurs in Region 1 and perhaps also in the eastern portion of 2 and the southern portion of 17.
  • Smilax (Smilax spp.) occurs throughout the eastern half of the state. The stretchberry, S. bona-nox, is the most common of all species, covering the entire range indicated above. Along rich stream bottoms and in sandy, piney uplands of 1 and 17 are found various species of beautiful evergreens, commonly called "Southern Smilax," much sought after for Christmas and wedding decorations. Other species also occur, S. cordifolia as far west as Region 7. Several herbaceous-stemmed species placed by some in the genus Nemexia are found in 1 and 2.
• Amaryllis Family: AMARYLLIDACEAE. Amaryllids, suited to a wide variety of conditions, are found in all regions:
  • Colic-root (Aletris spp.) ; in 1 and 2;
  • Yellow Star-grass (Hypoxis); in 1, 2, 16, 17;
  • False Aloe (Manfreda spp.); in 1, 2, 3, 5, 16, 17;
  • Century Plant (Agave americana); widely introduced;
  • Lechuguilla (Agave lechuguilla) ; 4, 7, 9, 10, 8;
  • Atamosco spp.; in 2, 3, 4, 5, 7, 9, 14, 15, 16, 18;
  • Rain Lily (Cooperia spp.); 2, 3, 4, 6, 7, 9, 13, 14, 15, 16, 17;
  • Crinum Lily (Crinum spp.) ; 1, 2, 17;
  • Spider Lily (Hymenocallis spp.); 1, 2, 3, 16, 17.
• Iris Family: IRIDACEAE.
  • Irids, members of the Iris family, except Iris itself, are all grass-like in vegetative appearance, and nearly all Texas forms have showy blue or purplish flowers. In order of wideness of distribution may be mentioned:
  • Blue-eyed grass (Sisyrinchium spp.); probably in all regions;
  • Nemastylis spp.; 1, 2, 3, 5, 16, 17;
  • Herbertia spp.; 1, 2, 3, 5, 16, 17;
  • Calydorea texana; 2, 3.
  • All might be appropriately called giant Blue-eyed grasses.
  • Eustylis purpurea is the most gorgeously deep purple (in places nearly black) and yellow mottled flower, perhaps in Texas; 1, 2, 3, 16, 17.
  • Iris hexagona, and other species, occur in swamps in 1, 2, 3, 16, 17.
• Canna Family: CANNACEAE. The family is represented by only two species of Arrow-root, Thalia dealbata and T. barbata, in open marshes or low wet prairies 1, 2, 16, 17. The plants resemble a slender Canna in growth habit, but the flowers are much smaller and purple.
 

 

50

• Burmannia Family: BURMANNIACEAE. The family is represented by a single collection of Burmannia capitata from a marsh in Gonzales County (16). The plants are very delicate, slender, and apparently leafless stalks with a few small, inconspicuous whitish flowers resembling those of a milkwort at the tip. It should be found in regions 1, 2 and 17.
• Orchid Family: ORCHIDACEAE. Orchids are represented by a dozen genera and two or three times that many species. They are most abundant in 1, 2, 16, 17; but also present in almost every region. All are terrestrial and most commonly found in marshy or wet soil. The most widespread genus is Spiranthes, which is found in the whole southeastern half of the state. Other genera are Habenaria, Blephariglottis, Pogonia, Serapias, Peramium, Corallorhiza, Limodorum, Hexalectris, Stenorrhynchus.
• Lizard's Tail Family: SAURURACEAE.
  • Lizard's-tail (Saururus cernuus) is abundant in swampy situations 1, 2, 16, 17. The name comes from the slender, tapering, drooping inflorescence which is sometimes nearly a foot long.
• Willow Family: SALICACEAE.
  • Willows (Salix spp.) occur in some half dozen species of which the Black Willow, S. nigra, is the most common. It is found on river banks almost throughout the state. The Sand-Bar Willow, S. luteosericea, is common on new dunes and bars along upper Red River and the Canadian. It is a densely growing shrub. Others occur in the extreme west and northwest.
  • Poplar (Populus spp.). Except the quaking aspen, P. tremuloides, found only in protected mountain gulches at high altitudes (8), all species of poplar are commonly called Cottonwood. The most common and widespread is the Eastern Cottonwood, P. balsamifera var. virginiana, which occurs along streams in 1, 2, 3, 4, 6, 7, 9, 13, 15, 16, 17, 18. Some 4 other species are found northwestward of these regions but in Texas they are uncommon.
• Myrtle Family: MYRICACEAE.
  • Wax Myrtle (Myrica cerifera) grows as a shrub or small tree in 1, 2, 16, 17. On the coastal prairie it is very scrubby, propagating by thick rhizomes; in the sandy uplands of 1 and 17 it is a shrub 4 to 10 feet tall; along marsh edges in 16 it attains a height of 15 to 20 feet and a diameter of nearly a foot.
• Cork-wood Family: LEITNERIACEAE.
  • Corkwood (Leitneria floridana); so called because of the extreme lightness of the wood, is found in Region 2 as far southwest as the lower Brazos, but is nowhere abundant.
• Walnut Family: JUGLANDACEAE. Walnuts are represented in regions 1, 16, 17 by Juglans nigra, the black walnut, and in 4, 5, 7, 8, 9, and 10 by J. rupestris, the small western walnut. The former is scattered sparsely on flood plains (creek and river bottoms); the latter is abundant in the   

 

51

boulder covered channels of arroyas, or on adjacent terraces, 9, 13 and westward.
• Hickories. The most widely distributed hickory in the sandy regions of East Texas (6, 7, 14, 15, 16, 17) is Hicoria buckleyi including its variety arkansana. The shell-bark occurs in bottomlands of 1 and 17; H. alba in 1, 16, 17; various bitter pecans in the bottomlands of 1, a, 16, 17; the pecan in bottomlands as far westward as Devil's River and northward to regions 9 and 13.
• Birch Family: BETULACEAE.
  • Birch (Betula nigra) is found along wet bottomlands and stream banks 1, 2, 16, 17. The thin pale, tannish bark, peeling off in curling flakes is conspicuous and definitely identifies the plant.
  • Ironwood (Carpinus caroliniana) is common on wet river bottoms in 1, 16, 17. It is a small elm-like tree with fluted trunk, smoothish bark and flattened one-seeded fruits.
  • Hop-hornbeam (Ostrya virginiana) resembles Ironwood and grows in similar situations in the same regions. The trunks are less fluted, the bark more scaly, and the one-seeded fruits inflated and bladder-like.
  • Alder (Alnus rugosa) is found along wet bottomlands in 1 and 17 .
• Beech Family: FAGACEAE.
  • Beech (Fagus grandifolia) occurs in moist hillsides and in swamps in 1, 2, 17. It frequently forms beautiful open groves, attaining its largest size (3 feet diameter, 100 feet tall) in the Big Thicket (Liberty County).
  • Chinquapin (Castanea pumila) occurs in 1, 2, 17, along moist sandy borders of stream bottoms.
  • Oak (Quercus spp.) is one of the most important genera of forest trees found in the state. Represented by some 50 species an adequate treatment of it would alone require a sizeable volume. In order of importance a few only of the most outstanding species will be enumerated:
    • Post-oak (Q. stellata) occurs dominant on sandy uplands westward to 6, 7, 14, and 15 and to the eastern portion of 9;
    • Black-jack (Q. marylandica) shares dominance with post-oak throughout much of its range;
    • Live-oak (Q. virginiana) is found from the coast to the Pecos, 2, 3, 4, 5, 6, 7, 9, both along the coast and in the Edwards Plateau, being locally dwarfed to a shrub;
    • Red-oak (Q. rubra) is a large forest tree in 1, 2, 16, 17;
    • White-oak (Q. alba); 1, 2, 17;
    • Basket-oak (Q. michauxi); 1, 2, 17;
    • Overcup oak (Q. lyrata); 1, 2, 17;
    • Blue-jack (Q. cinerea); 1, 2, 16, 17;
    • Durand's oak (Q. durandii); 2, 16, 17;
    • Emory's oak (Q. emoryi); 8;
    • Fendler's oak (Q. fendleri); 8;
    • Gambell's oak (Q. gambellii); 8, 9;
     

     

    52

    • Slender branched oak (Q. gracilliformis); 8;
    • Grey oak (Q. grisea); 8, 9;
    • Havard's oak (Q. havardii); 11, 12, 13;
    • White-leafed oak (Q. hypoleuca); 8;
    • Intricate oak (Q. intricata); 8;
    • Lacey's oak (Q. laceya); 7, 9:
    • Laurel leaved oak (Q. laurifolia); 1, 2;
    • Bur oak (Q. macrocarpa); along stream bottoms to the San Antonio River. 1, 2, 6, 7, 14, 16, 17;
    • Mohrian oak (Q. mohriana); 8, 9, 10, 13;
    • Muhlenberg's oak (Q. muhlenbergii); 1, 2, 7, 8, 9, 17;
    • Southern Pin Oak (Q. nigra); 1, 2, 16, 17;
    • Oblong leaved oak (Q. oblongifolia); 8;
    • Obtuse leaved oak (Q. obtusifolia); 8, 9, 10, 13;
    • Willow oak (Q. phellos); 1, 2, 17;
    • Net leaved oak (Q. reticulata): 8;
    • Rhombic leaved oak (Q. rhombica); 1, 2;
    • Robust oak (Q. robusta); 8;
    • Spanish oak (Q. shumardii); 2, 7, 16, 17;
    • Spanish oak (Q. texana); 6, 7, 8, 9, 10;
    • Undulate oak (Q. undulate); 8, 10;
    • Vaseyan oak (Q. vaseyana); 8, 10;
    • Yellow oak (Q. velutina); 1, 2, 6, 17.
• Elm Family: ULMACEAE; represented by:
  • Elm (Ulmus spp.) ; U. americana west to 6, 14; U. crassifolia 2, 3, 4, 6, 7, 9, 13; U. alata 1, 2, 16, 17; U. fulva 1, 2, 16, 17.
  • Planer tree (Planera aquatica); in swamps and low wet woods, 1, 16, 17.
  • Hackberry (Celtis spp.) ; all regions.
  • Granjeno (Celtis pallida); 4.
• Mulberry Family: MORACEAE; represented by:
  • Mulberry (Morus rubra); as far westward and Morus microphylla as far eastward as 7.
  • Bois d'Arc (Toxylon pomiferum); westward to 7 and 14. In early days planted as a hedge to control stock.
• Nettle Family: URTICACEAE; represented by:
  • Urtica chamaedryoides; 7, 9, 14 eastward.
  • Boehmeria; 7, 9, 14 eastward.
  • All are in moist shaded soil or adjacent to marshes.
• Mistletoe Family: LORANTHACEAE.
  • Mistletoe (Phoradendron); in addition to the common eastern mistletoe (P. flavescens); less common species of this and related genera occur westward. Some of these are dwarf, leafless forms on pines and related gymnosperms.
• Sandalwood Family: SANTALACEAE.
  • Bastard Toadflax (Comandra) occurs along the edge of Caprock (12).
 

 

53

• Birthwort Family: ARISTOLOCHIACEAE.
  • Aristolochia reticulata; 6, 16, 17.
  • Dutchman's Pipe (Aristolochia spp.): 7, 8, 9, 10.
• Buckwheat Family: POLYGONACEAE; abundantly represented, especially by the following:
  • Eriogonum, increasingly important westward, 6, 7, 8, 9, 10, 11, 12.
  • Rumex, in low grounds all regions.
  • Polygonum. (including Persicaria), low grounds along streams, all regions.
  • Brunnichia, a high climbing vine in regions 1, 2, 16, 17.
• Goosefoot Family: CHENOPODIACEAE; represented on the coast and in saline or alkali regions by species of Dondia, Salsola, Atriplex, Salicornia, Chenopodium; on the plains and in West Texas (10, 11, 12) by Sarcobatus, Eurotia, Corispernum, Allenrolfea; in 6, 7, 8, 9, 11, 13, 14, 15 by Cycloloma, Monolepis, Chenopodium.
• Pigweed Family: AMARANTHACEAE Members of this family are largely weeds in cultivated fields, especially in all sandy regions. None except the globe amaranth, Gomphrena, have conspicuous flowers or other distinctive characters which make possible a fruitful popular discussion within the limits herein obtaining. One or more of twelve or fifteen genera represent the family in every region of the state. The globe amaranth mentioned above is very similar to the cultivated bachelor's buttons, except that it grows prostrate on the ground and bears its bright pink heads on short upright branches some 6 to 8 inches tall. It is mostly found along the southern portion of Region 2 and the wet sandy portions of 5.
• Four O'Clock Family: ALLIONIACEAE.
  • Umbrella-worts (Allionia spp.) are common in great variety in all eastern regions and in moist shaded soils of ravines, hillsides and mountains in the west.
  • Four O'Clocks (Mirabilis spp.) also are not uncommon, especially in moist rich soil along streamways in 7, 8, 9, 10, 12, 13.
  • Midget Four O'Clock (Bochaavia spp.) are found in all regions.
  • Nyctaginia capitata, with its beautiful clusters of bright red flowers is found in sandy soils in 4, 5, 6, 7, 9, 10, 11, 12, 13.
  • Abronia, with showy clusters of pink or white flowers is found along with the preceding.
  • Wedelia and Acleisanthes are less showy, mostly prostrate forms which occur in regions 4, 7, 9, 13.
• Batis Family: BATIDACEASE. A single sprawling prostrate shrub with thick yellowish green succulent leaves, occurs along the immediate coast (2, 4) and is the sole representative of this family.
• Pokeweed Family: PHYTOLACCACEAE. The common Pokeweed, Phytolacca, and a dwarf red berried relative, Rivina, represent this family; the former  

 

54

in regions 1, 7, 14, 15, 16, 17, 18; the latter in regions 2, 4, 6, 7, 9.
A spinose shrubby member of the extreme southern coastal chaparral is Phaulothamnus.
• Carpet-weed Family: TETRAGONIACEAE. In Region 2 represented by the rather showy, purslane-like beach inhabitant, Sesuvium; in sandy regions throughout the state except the west by Mollugo (Carpet weed) a prostrate, small flowered weedy annual.
• Purslane Family: PORTULACACEAE. Represented as follows:
  • Talinum spp.; 4, 7, 9, 10, 13.
  • Spring Beauty (Claytonia); 1, 2, 16, 17 (and rarely 19).
  • Purslane (Portulaca); sandy soil, all regions.
• Whitlow-wort Family: CORRIGIOLACEAE. A single genus, Paronychia, of inconspicuous small-flowered weeds represents this family in regions 2, 4, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16.
• Chickweed Family: ALSINACEAE. Found mostly in moist shaded soil, some genera as Leoflingia in dry gravelly soil; the following genera common:
  • Tissa; 2 and saline situations inland;
  • Sagina; 1, 2, 6, 7, 9, 11, 12, 13, 14, 15, 16, 17;
  • Alsinopsis; a most attractive landscape feature in damp, sandy open places; 1, 16, 17;
  • Alsine ; widespread;
  • Arenaria ; 1;
  • Powder horn (Cerastium); widespread.
• Pink Family: CARYOPHYLLACEAE.
  • Silene, common in the southern states, is represented in the eastern regions (2, 3, 7, 9, 13 and eastward) by S. antirrhina, "Sleepy Catch-fly," and in the mountains (8) by the elegant red flowered S. laciniata.
  • Cow-herb (Vaccaria) also occurs in the easternmost regions (1, 17).
• Water Lily Family: NYMPHAEACEAE.
  • Nymphaea advena, with its glossy floating sinusate leaves and smallish bright golden hemispheric flowers occurs in slow streams and ponds westward to 9 and 13.
  • Castalia spp.; in delicate whitish pinks and blues are most abundant in coastal ponds (2, 4, 5) where they contribute greatly to the beauty of the landscape.
• Lotus Family: NELUMBONACEAE. A single species, Nelumbo lutea (Yonquepin, Duck Acorn, Water Chinquapin) grows abundantly in still or sluggish water westward as far as 18. The pale lemon-yellow flowers as large as small dinner plates, raised on naked stalks well above the water surface, are quite attractive, as is also the yellow-green conspicuously raised peltate foliage.
• Watershield Family: CABOMBACEAE.
  • Cabomba and Brasenia both inhabit ponds and slow streams in 1, 2, 17.
 

 

55

• Hornwort Family: CERATOPHYLACEAE.
  • The Hornwort (Ceratophyllum) occurs in swamps, marshes and open water in regions westward to 7.
• Crowfoot Family: RANUNCULACEAE. This large family is well represented in Texas, the following genera being particularly widespread: Delphinium, Clematis, Anemone, Ranunculus. Other genera of interest are Aquilegia (Columbine); A. canadensis in moist shaded ravines 7 and 9; A. longissimus in moist canyons 8; Myosuris (Mouse-tail) along silt deposits bordering streams westward to 7, 9, 13; Thalictrum, wet prairies, northeastern portion of 3.
• Barberry Family: PODOPHYLLACEAE.
  • May-apple (Podophyllum) is found abundantly in open moist pine woods 1, 2, 17.
  • Barberry; Agarita (Berberis trifoliata) is found from 7 westward; Berberis swazeyi 7, 9; B. haemitocarpa in the mountains, 8.
• Moonseed Family: MENISPERMACEAE.
  • Moonseed (Cebatha carolina) is widely distributed westward to 4, 9, 12, 13.
• Magnolia Family: MACNOLIACEAE.
  • Large-flowered Magnolia (Magnolia grandiflora) occurs westward to 1, 17. In addition several other sorts are to be found in 1.
• Custard Apple Family: ANONACEAE.
  • Paw-paw (Asimina triloba) occurs in deep sand of 16, 17. An undetermined species occurs in the southwestern prong of 16.
• Laurel Family: LAURACEAE.
  • Sweet Bay (Persea spp.); 1, 2, 17.
  • Sassafras; 1, 2, 16, 17.
  • Benzoin; 1, 2, 7, 17.
• Fumatory Family: FUMARIACEAE.
  • Corydalis (Capnoides) is the sole representative; known commonly as Butter-and-eggs. It occurs as several species, ranging westward to 9, 12, 13.
• Poppy family: PAPAVERACEAE.
  • Prickly Polly (Argemone) is the sole natural representative in Texas. It occurs northeastward in white (A. alba; A. platyceras); southwestward (4) as pink to red (A. rosea) and yellow (A. Mexicana).
• Mustard Family: BRASSICACEAE.
  • Such a wide variety of genera representing this family is found in Texas that it is impossible to do more than give a scant suggestive enumeration. Widespread are Pepper-grass (Lepidium); Bladderpod (Lesquerella); Shepherd's Purse (Bursa); Hedge Mustard (Sisymbrium); Whitlow Grass (Draba); Rock Cress (Arabis); and Water-cress (Roripa). Restricted to western regions (4, 7, 9, 13 and westward) are Synthlipsis   

   

  56

  4: Streptanthus, Thelepodium, Erysimum, Dryopetalon, Greggia, Thlaspi, Dithyraea. Along the coast (2) is Cakile.
  • Eastern genera of lesser importance are Coronopus (2, 4), lodenthus (1, 2, 17), Erysimum (16, 17), Cardaminc (1, 2, 16, 17), Leavenzoorthia (1, 17), Euklisia (16, 17).
• Caper Family: CAPPARIDACEAE. Representing the family in Texas are:
  • Cristatella; (13, 14, 15, 16, 17, 18) in sand.
  • Clammy Weed (Polanisia); sandy portions of all regions.
  • Cleomella: (7, 14 westward in sand).
  • Cleome; (16, 17 in sand).
• Mignonette Family: RESEDACEAE.
  • Dipetalia: 8, 10.
• Pitcher Plant Family: SARRACENIACEAE.
  • Pitcher Plant (Sarracenia); grows in wet acid soil in regions 1 and 17.
• Sun-dew Family: DROSERACEAE.
  • Sun-dew (Droscra spp.) is the only representative. It occurs in wet acid soil in 1, 2, 16, 17.
• Stone Crop Family: SEDACEAE Three genera of this family occur native:
  • Midget stone-crop (Tillaeastrum) : in water-logged acid soil; 1, 2, 6, 15, 16, 17, 18:
  • Lenophyllum, a semi-shrubby stonecrop on dry gully banks bordering Corpus Christi Bay; and
  • Sedum, Stonecrop, in sandy-gravelly soil: 15 and 16 westward.
• Saxifrage Family: SAXIFRAGACEAE.
  • Five genera of the family are found, Lepuropetalon and Micranthes in wet acid soil in regions 1, 2, 16, 17;
  • Heuchera in the mountains, 8:
  • Fendlera; 7, 8 9, 10; and Whipplea 8.
• Hydrangea Family: HYDRANGEACEAE.
  • Mock Orange (Philadelphus) is found in regions 7, 8, 9, in rich moist shaded soil.
• Gooseberry Family: GROSSULARIACEAE.
  • Gooseberry (Grossularia campestris) is found in moist woods; 1, 17.
  • Currant (Ribes odoratuni) occurs on canyons bordering the Concho in Tom Green County (9) and beyond the Pecos (10).
• Virginia Willow Family: ITEACEAE.
  • Itea is found in swampy grounds in Region 1.
• Sweetgum Family: AI.TINGIACEAE.
  • Sweetgum; Redgum (Liquidambar); in rich bottomlands and on sandy uplands in 1, 2, 17 and locally in 16.
• Witch Hazel Family: HAMAMELIDACEAE.
  • Witch Hazel (Hamamelis) grows in rich moist soil. Region 1.
 

 

57

• Sycamore Family: PLATANACEAE.
  • The Sycamore (Platanus occidentalis) is found as a forest tree in 1, 16, 17; also in rocky arroyas as far west as the Pecos (6, 7, 9).
• Rose Family: ROSACEAE.
  • The most common genera are:
  • Rubus (Blackberries and Dewberries): as far west as 4, 7, 9, 13:
  • Rosa (Roses); westward to 15, 16; R. bracteata introduced farther, 2. 7, 9, 13;
  • Geum (Avens): westward to 7, 9, 13:
  • Potentilla, Cercocarpus, Physocarpus, Cowania, Fallugia, Spiraea, Eriogynia in 8 and/or 10 and 12.
• Peach Family: AMYGDALACEAE.
  • Represented as follows:
  • Peach (Amygdalus); escaped cultivation and growing spontaneously west to 7, 9, 13;
  • Plum (Prunus spp.); growing wild or escaped cultivation in all regions except perhaps 10-11.
  • Choke Cherry (Padus serotina); in 12, 3, 6, 7, 8, 9, 16, 17.
  • Wild Peach (Laurocerassus); in 1, 2, 16, 17.
• Apple Family: MALACEAE.
  • Crab-apple (Pyrus coronaria) is found in a restricted portion of 6 and 7 (Blanco, Kerr, Llano counties).
  • Red Haw (Crataegus spp.); including the May Haw; the genus is found in one of more species in 1, 2, 3, 6, 7, 8, 13, 14, 15, 16, 17 (May Haw in 1, 2, 17). The greatest variety occurs in 1, 2, 16, 17 where Haw thickets in bloom in March and April are outstanding landscape features.
• Mimosa Family: MIMOSACEAE.
  • Abundantly represented, especially in regions 4, 6, 7, 8, 9, 10, 11, 12, 13 by thorny "brush" denominated by the Mexican from pioneer days as "Chaparral." The principal genera are:
  • Acacia (Black brush, Cat-Claw, Huajillo, Huisache); occurring in 8 to 10 species (huisache occurs on coastal shell banks as far east as southern Louisiana):
  • Mimosa (Cat-claw); 2, 4, 6, 7, 9, 10, 11, 13;
  • Mesquite (Prosopis); extending eastward to 1, 17;
  • Pink sensitive briar (Morongia); all regions except perhaps 8 and 10;
  • Yellow briarless sensitive Plant (Neptunia); westward to 2, 3, 6, 7, 9, 13;
  • Acuan; all regions.
  • Genera restricted to 4, lower 2 and lower 10 are;
  • Texas ebony (Siderocarpos) ;
  • Dwarf Screw-bean (Strombocarpos).
• Senna Family: CASSIACEAE.
  • Senna (Cassia spp.) has representative species in all regions.
  • Partridge Pea (Chamaecrista spp.) is mostly confined to the eastern half of the state.
   

   

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  • Hoffmanseggia, a showy-flowered genus of small perennial herbs, extends eastward to 13, 9, 7, 4.
  • Redbud (Cercis spp.) ; occurs as C. canadensis westward to 16; as C. reniformis eastward to 18.
  • Honey locust (Gleditsia spp.): is found westward to 7, 9, 13.
  • Horsebean (Parkinsonia); is a sub-tropical genus extending from Mexico to the southern portion of 3, 7, and 8;
  • Cercidium is likewise a sub-tropical genus, confined to 4 and perhaps 10.
• Krameria Family: KRAMERIACEAE occurs as the single genus Krameria as far east as 18. Its westernmost representatives (4, 7, 10) are small shrubs; its eastern is a prostrate herb with deep maroon flowers and spiny fruits.
• Pea Family: FABACEAE. A large family widely distributed as follows:
  • Texas Mountain Laurel (Sophora secundiflora); with glossy evergreen foliage and showy blue blossoms in southwest Texas as far north as 7 and east to the vicinity of Austin (S. affinis, with very pale pinkish flowers and pods greatly constricted between the seeds in an eastern species which occurs westward to 4, 7, 18).
  • White Locust (Robinia): west to 16; widely introduced as a shade tree.
  • Amorpha ; westward to 4, 7, 13.
  • Wild Indigo (Baptisia) : in a great variety of species extends westward to 15, 16, 5, particularly in the southern regions.
  • Rattle-box (Crotalaria spp.); is represented by 4 or 5 species.
  • Bluebonnet (Lupinus): is represented by 4 or 5 species. In Central Texas the beautiful L. texensis, popularly supposed to be the state flower, is not so in fact, L. subcarnosus having been specifically set apart by the legislature for that honor. The latter grows in sandy soil in the southern portion of 16 only.
  • Bur Clover (Medicago) ; in 3 or 4 species occurs widely westward to 4, 7, 13.
  • Sweet Clover (Melilotus spp.); westward to 4, 7, 13.
  • Clover (Trifolium spp.); westward to 4, 7, 13.
  • Lotus; westward to 14 and in 8.
  • Indigo Plant (Indigofera spp.) : westward to 4, 7, 13.
  • Goat's Rue (Cracca spp.) ; westward to 6, 7, 14.
  • Coursetia; 4.
  • Sesban; westward to 6, 7.
  • Glottidium; westward to 15, 16.
  • Senna Bean (Daubentonia); westward to 15, 9, 13.
  • Ground-plum (Geoprummon): all regions, except perhaps 1, 2, 4, 5, 8, 10.
  • Astragalus (including Hamosa, Holophacos, Phaca, Xylophacos, Oxytropis) ; one or more in every region.
  • Psoralea spp.; widespread.
  • Eysenhardtia; 4, 7, 9, westward.
  • Parosela; widespread.
  • Prairie Clover (Petalostemon); widespread.
  • Joint Vetch (Aeschynomene); westward to 17.
   

   

  59

  • Zornia; westward in sand to 4, 6.
  • Stylosanthes; westward to 16.
  • Beggar's Ticks; Beggar-lice (Meibomia); widespread in rich moist shaded soil.
  • Bush Clover (Lespedeza); widespread.
  • Dolicholus; westward to 4, 9, 13.
  • Coral Bean (Erythrina) ; 1, 2, 4, 16, 17, 18.
  • Milk Peanut (Falcata) ; 1, 2, 6, 17.
  • Butterfly Pea (Bradburya); westward to 6, 7, 8, 14.
  • Clitoria; westward to 1, 2, 6, 14, 17.
  • Wild Bean (Apios) ; westward in sand to southern 16.
  • Strophostylis; all regions except perhaps 12, 13.
  • Cologania; 8.
  • Canavalia; 2.
  • Vicia spp.; westward to 4, 8, 7, 9, 13.
  • Lathyrus; 1, 2, 6, 7, 9, 10, 13.
• Geranium Family: GERANIACEAE.
  • Geranium spp.; westward to 6, 7, 15 (also 8).
  • Erodium; 7, 9, 13 westward.
• Oxalis Family: OXALIDACEAE.
  • Oxalis spp.; in great variety of vegetative appearance and in both yellow and rose colored flowers are found in all regions.
• Flax Family: LINACEAE.
  • Wild Flax (Linum spp.); occurs widespread.
• Caltrop Family: ZYGOPHYLLACEAE.
  • Sand-bur (Tribulus); in sand or limestone soil 16 westward.
  • Kallstroemia (similar to Tribulus but lacking the bur fruits); all regions.
  • Creosote bush (Covillea); 10, 14.
  • Porliera; 4.
• Rue Family: RUTACEAE.
  • Dutchman's Breeches (Thamnosma); 7, 9, 10, 13.
  • Prickly Ash (Xanthoxalum spp.); 1, 2, 4, 14, 15, 16, 17, 18.
  • Helietta; 2, 4.
  • Hop tree; skunk bush (Ptelea); 1, 2, 4, 6, 7, 8, 9, 10, 15. 16, 17.
  • Torchwood (Amyris) ; 2, 4.
• Quassia Family: SlMARUBACEAE.
  • Castela; 4, 6, 7, 9, 13.
  • Tree-of-Heaven (Ailanthus); introduced in Central Texas regions from China.
• Mahogany Family: MELIACEAE.
  • China-tree (Melia); introduced from Asia and widely escaped.
 

 

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• The Vegetation of Texas
  • Malpighia Family: MALPIGHIACEAE.
  • Malpighia; 2, 4.
  • Thryallis; 4, 7, 9 and westward.
  • Aspicarpa; 7, 9, 10.
  • Janusia; 7, 9, 10.
• Milkwort Family: POLYGALACEAE.
  • Milkwort (Polygala spp.); widely distributed, all regions.
• Spurge Family: EUPHORBIACEAE
  • A large family with a great variety of genera. Representatives in Texas:
  • Andrachne; 7, 9.
  • Leaf-flower (Phyllanthus); 1, 2, 4, 6, 7, 9, 10, 13, 14, 15, 16, 17.
  • Reverchonia; 4, 7, 9, 10.
  • Goat-weed (Croton spp.); as annual and perennial herbs and shrubs present in all regions.
  • Crotonopsis; 1, 7, 15, 16, 17.
  • Three-Seeded Mercury (Ditaxis); westward to 4, 7, 9, 13.
  • Ricinella; 4.
  • Bernardia; 4, 7, 9, 10.
  • Acalypha; all regions.
  • Spurge Nettle (Tragia); widespread.
  • Prince's Spurge: Queen's Delight (Stillingia) ; widespread.
  • Castor Bean (Ricinus) ; naturalized; widespread in cultivation and escaped along streams.
  • Rubber-bush (Mosinna) ; 4 and southern 10. So-called because of the pliability and toughness of the sterns, which permit them to be tied in knots.
  • Bull-Nettle (Jatropha) ; westward to 4, 9, 13.
  • Spurges (the following genera are placed by many authorities in one large genus-Euphorbia)
  • Chamaesyce; mostly prostrate carpet-weed like annual or perennial herbs, one or more species in every region.
  • Zygophyllidium; sand 11, 12, 13, 14, 15, 16.
  • Tricherostigma (Candalilla); dry mesas 10.
  • Snow-on-the-mountain (Dichrophyllum); westward in all provinces 4, 7, 9, 12.
  • Tithymalopsis; one or two species in sand westward to 7, 14.
  • Tithymalus; represented by one or more species in all regions.
  • Poinsettia; shaded, moist rich, soil all regions.
• Water Starwort Family: CALLITRICHACEAE.
  • Water Starwort (Callitriche spp.); in clear ponds or running water and/or on moist soil mostly in eastern regions.
• Sumac Family: SPONDIACEAE.
  • Smoke Tree (Cotinus) ; 1, 17.
  • Poison oak; Posion ivy (Rhus spp.); all regions, perhaps; possibly not in 5 or 11.
   

   

  61

  • Sumac (Schmaltzia) ; one or more species in every province, except perhaps 5, 11.
• Titi Family: CYRILLACEAE.
  • Red or White Titi (Cyrilla); and perhaps Black Titi (Cliftonia) 1, 2
• Holly Family: AQUIFOLLACEAE.
  • Holly; a single genus (Ilex) represented in the extreme eastern regions by several species, two of which extend westward to 6, 7, 14.
• Staff-tree Family: CELASTRACEAE.
  • Strawberry bush (Euonymus); 1, a, 16, 17.
  • Maytenus; southern part of region 2.
  • Yellow-wood (Schaefferia); 2, 4, 7, 9, 10.
  • Mortonia; 4, 8, 10.
• Maple Family: ACERACEAE.
  • Maple (Acer) ; occurs as several eastern species in 1, 2, 17; as 1 or 2 western species in 7, 8.
  • Box-elder (Rulac); westward to 7, 9.
• Buckeye Family: AESCULACEAE.
  • Buckeye (Aesculus) ; westward to 6, 7, 9.
  • Soapberry Family: SAPINDACEAE.
  • Urvillea; 4.
  • Serjania; 4.
  • Sapindus; all regions.
  • Mexican Buckeye (Ungnadia) ; 6, 7, 8, 9, 10.
  • Cardiospermum; all regions.
• Buckthorn Family: RHAMNACEAE.
  • Bluewood; Purple Haw (Condalia); 6, 7, 18 westward.
  • Lotibush (Zizyphus); 4, 6, 7, 9, 10, 13.
  • Karwinskia; 4, 7, 10.
  • Rattan (Berchemia); westward to 7, 14, 16.
  • Buckthorn (Rhamnus) ; westward to 6, 7, 14.
  • New Jersey Tea (Ceanothus); most regions.
  • Colubrina; 4, 7, 9, 10.
• Grape Family: VITACEAE.
  • Grape (Vitis spp.) ; one or more in every region except perhaps 5, 11.
  • Muscadine (Muscadinia) ; 1, 2, 16, 17.
  • Cissus; all regions, perhaps.
  • Cow-itch; sarsaparilla (Ampelopsis); westward to 4, 6, 7, 9, 14.
  • Virginia Creeper, American Ivy (Parthenocissus) ; all regions except perhaps 5, 11.
• Linden Family: TILIACEAE.
  • Linden; Basswood (Tilia); 1, 2, 16, 17.
  • Corchorus; 4, 6, 7, 9.
 

 

62

• Mallow Faintly: MALVACEAE.
  • Indian Mallow (Abutilon spp.); all regions.
  • Wissadula; 4, 6, 7, 9, 10, 12.
  • Modiola; westward to 15, 16.
  • Poppy Mallow; Wine Cup; Wild Hollyhock; (Callirrhoe) ; westward to 4, 6, 7, 9, 12, 13.
  • False Mallow (Malvastrum); all regions.
  • Sida; all regions.
  • Malochia; 2, 4.
  • Pavonia; 4, 7.
  • Indian Apple (Malvaviscus); 2, 4, 6, 7, 9, 10, 15, 14, 16.
  • Hibiscus spp., all regions.
  • Koesteletzka; 2.
  • Cienfugosia; 2, 4.
  • Anoda; 4, 7, 8, 9, 10
• Chocolate Family: BUETNERIACEAE.
  • Hermannia; 4, 7, 10.
  • Melochia; 4, 7, 10.
  • Ayenia; 4.
  • Nephropetalum : 4.
  • Waltheria; 4.
• St. John's-Wort Family: HYPERIACEAE.
  • St. Peter's-Wort (Ascyrum); 1, 2, 7, 16, 17.
  • St. John's Wort (Hypericum.); widespread, wherever local marshy conditions obtain.
  • Sarothra; westward in sand to 6, 14, 16.
  • Marsh St. John's Wort (Triadenum) ; in swamps and about stumps in shallow water; 1, 2, 4, 17.
• Waterwort Family: ELATINACEAE.
  • Mud Purslane (Elatine) ; 1, 2, 16, 17.
  • Bergia; 2, 4, 7, 10.
• Tamarix Family: TAMARICACEAE.
  • Salt Cedar (Tamarix); widely naturalized 2, 4, 13.
• Coach-Whip Family: FOUQUIERACEAE.
  • Candlewood; Ocotillo; Coachwhip (Fonquiera) ; 10.
• Rock-rose Family: CISTACEAE.
  • Rock-rose (Helianthemum); widespread in gravelly-sandy soil westward to 5, 16, 11.
  • Pinweed (Lechea); essentially like rockrose in habitat and range.
• Bixa Family: BIXACEAE.
  • Amoreuxia; 4.
• Allthorn Family: KOEBERLINIACEAE.
  • Allthorn (Koeberlinia); 4, 8, 9, 10.
 

 

63

• Violet Family: VIOLACEAE.
  • Violet (Viola spp.); by one or more species represented in wooded localities westward to 6, 7, 14.
  • Green Violet (Calceolaria); eastward to 18 and 3.
• Flacourtia Family: FLACOURTTACEAE.
  • Flacourtia; 4 (Cameron County).
• Turnera Family: TURNERACEAE.
  • Turnera; 4.
• Passion Flower Fancily: PASSIFLORACEAE.
  • Widely represented by various spp. in moist shaded situations; in 1, 2, 16, 17 by the beautiful May-pop, P. incarnata, which is common along field fences.
• Loasa Family: LOASACEAE.
  • Mentzelia; widespread.
  • Nuttallia; sandy, 4, 5, 6, 7, 9, 11, 12, 13, 14, 15.
  • Eucnide; seepy limestone bluffs, 7, 9, 10, 11.
  • Cevallia; 4, 7, 10.
• Cactus Family: OPUNTIACEAE.
  • Prickly Pear (Opuntia spp.); occurs in one or more species in every region.
  • Pincushion Cacti (Echinocactus spp.); are widespread westward from 16, 15, 3.
  • Echinocereus, Wilcoxia, and others occur in the regions west of central Texas. (A treatment of the family by Runyan and Schulz is Texas Cacti, published by the Texas Academy of Science. Available from Witte Memorial Museum at San Antonio, Texas.)
• Eleagnus Family: ELEAGNACEAE.
  • Eleagnus; 10.
• Loosestrife Family: LYTHRACEAE.
  • Water Purslane (Didiplis); 1, 2, 4.
  • Ammann's loosestrife (Ammannia); wet soil and pond edges all regions except perhaps 8, 11, 12.
  • Rotala; westward to 4, 7, 13.
  • Heimia; 2, 4, 5, along water margins.
  • Loosestrife (Lythrum.); widespread in moist or wet open places.
• Meadow Beauty Family: MELASTOMACEAE.
  • Meadow Beauty (Rhexia) ; westward to 16 in open sunny marshes and wet pinelands.
• Evening Primrose Family: EPILOBIACEAE.
  • Isnardia; marshes and swamps, all regions.
  • Ludwigia; westward to 15, 16.
  • Jussiaea; widespread in marshes and along stream banks.
   

   

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  • The Vegetation of Texas
  • Evening Primrose (Oenothera); all regions.
  • Standing honeysuckle (Gaura spp.) ; all regions.
  • Standing honeysuckle (Stenosiphon spp.); 12, 13, 14, 15.
• Water Milfoil Family: GUNNERACEAE.
  • Mermaid Weed (Proserpinaca); 1, 2, 17.
  • Water Milfoil (Myriophyllum); ponds and streams; widespread.
• Ivy Family: HEDERACEAE.
  • Hercules' Club (Aralia); 1, 2, 17.
• Carrot Family: AMMIACEAE.
  • Marsh Pennyroot (Hydrocotyle) ; all regions.
  • Bowlesia; 2, 4, 6, 7, 9 westward.
  • Canada Snake-root (Sanicula); moist shaded localities along streams, all regions except 5, 10, 11, 13.
  • Button Snake-root (Eryngium) ; all regions.
  • Chervil (Chaerophyllum) ; west to 4, 7, 9, 13.
  • Hedge Parsley (Torilis); widespread.
  • Bifora; 7, 9, 12, 13, 14, 15, 16, 17.
  • Apiastrum; 12, 13, 14, 15, 16.
  • Museniopsis; 7, 9, 13, 4, 2.
  • Trepocarpus; 7, 14, 15, 16, 17.
  • Aletes; 8 (Chisos Mts.).
  • Sand Parsley (Ammoselinum) ; westward to 4, 7, 9, 11, 12, 13.
  • Ammi; 2, 4, 7, 9.
  • Cut-leaved Water Parsnip (Berula) ; 2, 6, 7, 9, 10.
  • Conium; 7, 9.
  • Coriandrum; 7, 8 (introduced).
  • Cymopterus; 7, 9, 10, 12, 13.
  • Cynosciadium; 1, 2, 4, 7, 16, 17, 18.
  • Daucus; westward to 4, 7, 9, 13.
  • Eurytaenia; 2, 3, 4, 7, 9, 13, 18.
  • Oreoxis; 8 (Davis and Guadalupe Mts.).
  • Oxypolis; 1, 2, 17.
  • Phanerotaenia; 2, 6, 7, 9, 12, 13, 15, 16, 17.
  • Phellopterus; 7, 9, 12, 13.
  • Polytaenia; 6, 7, 9, 18.
  • Pseudocymopteris; 8 (Davis).
  • Ptilimnium; 2, 1, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 16, 17, 18.
  • Water Parsnip (Siam); 1, 2, 3, 7, 16, 17.
  • Spermolepis; all regions.
  • Trepocarpos; 1, 2, 17.
• Dogwood Family: NYSSACEAE.
  • Blackgum (Nyssa spp.); 1, 2, 16, 17.
  • Dogwood (Cornus spp.); 1, 6, 7, 14, 15, 16, 17, 18.
  • Garrya; 6, 7, 8, 9, 10.
 

 

65

• Heath Family: ERICACEAE.
  • Honeysuckle (Azalea); 1, 2, 17.
  • Pieris; 1, 2, 17, 16.
  • Madrona (Arbutus) ; 7, 8, 9, 10.
• Huckleberry Family: VACCINIACEAE.
  • Gaylussacia, Polycodium, Vaccinium, and Batodendron all occur in 1. The last also ranges westward to 16.
• Primrose Family: PRIMULACEAE.
  • Water Pimpernel (Samolus) ; all regions.
  • Shepherd's Weather-vane (Anagallis) ; westward to 4, 7, 9, 13.
  • Shooting Star (Dodecatheon); Limestone ledges, 7, 9.
  • False pimpernel (Centunculus) ; 1, 2, 4, 5, 6, 7.
  • Featherfoil (Hottonia) ; 1, 17.
  • Steironenia; 1.
• Plumbago Family: AMERIACEAE.
  • Lintonium; 2, 4, 16 (Gonzales Co.).
• Sapodilla Family: SAPOTACEAE.
  • Gum Elastic, Chittam Wood (Bumelia); 4, 9, 13 eastward.
• Ebony Family: EBENACEAE.
  • Persimmon (Diospyrus); westward to 16.
  • Mexican Persimmon (Brayodendron) ; 6, 7, 9, westward.
• Storax Family: STYRACACEAE.
  • Storax (Styrax) ; 1, 6, 7, 17.
  • Halesia; 1, 2.
• Sweet Leaf Family: SYMPLOCACEAE.
  • Sweet Leaf (Symplocus); 1, 17.
• Olive Family: OLEACEAE.
  • Crooked Bush (Adelia) ; 1, 2, 4, 6, 7, 8, 9, 10, 12, 13, 15, 16, 17, 18.
  • Grandaddy Greybeard, Fringe-tree (Chionanthus) ; 1, 2, 17.
  • Ash (Fraxinus spp.); All regions except 3, 5, 11, 12.
  • Menodora; 2, 4, 6, 7, 8, 9, 10, 11, 13, 14, 18.
  • Menodoropsis; 7, 8, 9, 10.
• Logania Family: SPIGELIACEAE.
  • Buddleia; 4, 6, 7, 8, 9, 10, 11, 12, 13.
  • Yellow Jasmine (Gelsentium) ; 1, 2.
  • Coelostylis; 2, 4, 10.
  • Cynoctonum; 1,2, 3,6,7,14,15,16,17.
  • Spigelia; 1, 14,6,7,9,14,15,16,17.
  • Polypremum; 1, 2, 5,
• Gentian Family: GENTIANACEAE.
  • Centaury (Erythraea) ; 4, 6, 7, 9, 10, 13.
   

   

  66

  • The Vegetation of Texas:
  • Texas Blue Bell (Eustoma) ; widespread but highly localized in moist meadows.
  • Pink Texas Star (Sabbatia); 1, 2, 6, 14, 15, 16, 17.
  • Floating Heart (Limnanthemum) ; 1, 2.
• Dogbane Family: APOCYNACEAE.
  • Amsonia; widespread but nowhere abundant except 7, 9.
  • Dogbane (Apocynum); widely distributed but not abundant.
  • Macrosiphonia; 7, 8, 9, 10.
  • Trachelospermum; 2, 16 (southern part).
  • Periwinkle (Vinca); occasionally escaped westward to 16, 7, 15.
• Milkweed Family: ASCLEPIADACEAE.
  • Green Milkweed (Acerates) ; widespread.
  • Milkweed (Asclepias spp.); all regions.
  • Butterfly weed (A. tuberosa) ; westward in sand to 4, 9, 11.
  • Reclining Milkweed (Asclepidora) ; westward from 16, 2.
  • Smooth fruited climbing milkweed (Gonolobus); 18 westward.
  • Midget Milkweed (Metastelma) ; 2, 4, 7, 9, 13 westward.
  • Philibertella; 18, 3, 4, westward.
  • Podostemma; 13.
  • Roulinia; 7, 10, 16.
  • Seutera; 2.
  • Rough fruited Milkweed (Vincetoxicum); widespread.
• Morning glory Family: CONVOLVULACEAE.
  • Carpet Morning glory (Dichondra) ; all regions.
  • Breweria; deep sand 15, 16, 2, and eastward.
  • Bindweed (Convolvulus) ; 2, 3, 16, 18 westward.
  • Cressa; 2, 4, 8, 9, 10, 11.
  • Dodder, Love-vine (Cuscuta) ; all regions.
  • Evolvulus ; 2, 4, 15, 16 westward.
  • Morning Glory (Ipomoea spp.); all regions in great variety of habit and appearance.
  • Jacquemontia; 1, 2, 17.
  • Pharbitis; widespread.
  • Quamoclit; 8, 10.
• Phlox Family: POLEMONIACEAE.
  • Phlox; widespread, all regions.
  • Gilia; all regions.
• Water-leaf Family: HYDROLEACEAE.
  • Nama; widespread.
  • Baby Blue-eyes (Nemophila) ; 5, 7, 15 eastward.
  • Blue Curls (Phacelia) ; 2, 16 and westward.
• Borage Family: BORRAGINACEAE.
  • Cochranea; westward in sandy gravelly soil to 7, 14, 16.
  • Coldenia; 2, 4, 7, 8, 9, 10, 13 westward.
   

   

  67

  • Cordia; 4.
  • Cryptanthe; 15, 16 westward.
  • Eddya; 10.
  • Ehretia elliptica; 2, 4, 7, 16.
  • Euploca; 2, 4, 15, 16 widespread in sand.
  • Heliotrope (Heliotropium); all regions.
  • Krynitzkia; 10.
  • Lappula; 16 westward.
  • Stone-Seed (Lithospermum); all regions.
  • Myosotis; 15, 16 and eastward.
  • Onosmodium; 15, 16 and westward.
  • Oreocarya; 8, 9, 10, 11, 12, 13.
  • Tournefortia; 4.
• Vervain Family: VERBENACEAE.
  • Black Mango (Avicennia) ; 2 (saline marshes).
  • Bouchea; 4, 10.
  • Mulberry, French (Callicarpa) ; 1, 2, 7, 16, 17.
  • Citharexylum; 4.
  • Duranta; 4.
  • Goniostachyum; 4.
  • Helleranthus; 4.
  • Lantana; 2, 3, 4, 5, 6, 7, 15, 16 westward.
  • Lippia; all regions.
  • Vervain (Verbena spp.); all regions.
• Mint Family: LAMIACEAE.
  • Agastache; 8, 10.
  • Lemon mint (Hedeoma) ; all regions.
  • Hyptis; 1, 2.
  • Isanthus; 7.
  • Koellia; 1, 2, 17.
  • Henbit (Lamium); 4, 6, 17, 13 westward.
  • Leonotis; westward to 7.
  • Marsh Hoarhound (Lycopus) ; 1, 2, 6, 7, 17.
  • Hoarhound (Merrubium) ; widespread: introduced.
  • Trichostema; 1, 2, 7, 9, 17.
  • Mint (Mentha spp.); widely introduced.
  • Micromeris; 4, 7, 9.
  • Horsemint (Monarda) ; all regions.
  • Perilla; 17.
  • Lion's Head (Physostegia); westward to 6, 7, 9.
  • Poliomintha; 8, 10.
  • Prunella; westward to 16.
  • Sage (Salvia spp.); all regions.
  • Skull cap (Scutellaria); all regions.
  • Stachydeoma; westward to 16.
  • Stachys; all regions except perhaps 11, 12, 13.
   

   

  68

  • Tetraclea; 4, 8, 9, 10, 13.
  • Teucrium; westward 3, 7, 9, 13.
• Nightshade Family: SOLANACEAE.
  • False Bindweed (Bouchetia); 4, 7, 9, 10, 13.
  • Chilipetin (Capsicum baccatum); 4, 7, 9, 10.
  • Chamaesaracha; 2, 4, 6, 7, 8, 9, 10, 12, 13.
  • Datura spp.; widespread but not abundant.
  • Leptoglottis; 4, 10.
  • Lycium; 2, 4, 7, 8, 10, 11, 18.
  • Margaranthus; 8 (Davis).
  • Wild Tobacco (Nicotiana) ; 4, 6, 7, 8, 9, 10, 13, 14, 15, 16.
  • Petunia; 4, 6, 7, 9, 10.
  • Ground Cherry (Physalis) ; all regions.
  • Purple Ground Cherry (Quincula) ; 4, 6, 7, 8, 9, 10, 12, 13.
  • Nightshade (Solanum spp.); all regions.
  • Cestrum ; 2, 4.
  • Cherry tomato (Lycopersicon) ; widely escaped cult.
• Figwort Family: SCROPHULARIACEAE.
  • Agalinis; all regions.
  • Climbing Fox-glove (Antirrhinum); 4, 6, 7, 9, 10, 13.
  • Aureolaria; westward to 16.
  • Monniera; 1, 2, 3, 4, 5, 6, 7, 8, 9, 13, 14, 15, 16, 17, 18.
  • Buchnera; 1, 2, 7, 16, 17.
  • Cagesia; 8 (Chisos).
  • Paint Brush (Castilleja) ; widespread all regions.
  • Collinsia; 16, 17.
  • Conobea; 6, 7, 9, 13.
  • Globifera; 1, 2.
  • Gratiola; 1, 2, 16, 17.
  • Hydrotrida; 1, 2.
  • Hysanthes; 1, 2, 16, 17.
  • Leucophyllum; 4, 7, 8, 9, 10.
  • Toad Flax (Linaria) ; westward to 4, 6, 7, 13.
  • Mecardonia; 1, 2, 4, 6, 7, 9, 8, 16, 17.
  • Micranthemum; 1, 2.
  • Mimulus; widespread in seeps and marshes.
  • Otophylla; 7, 13.
  • Pedicularis; 1, 17.
  • Beard Tongue; Pentstemon: all regions.
  • Seymeria; 7, 8, 9, 10.
  • Stemodia; 2, 4.
  • Tragiola; 1, 2.
  • Mullein (Verbascum); 1, 6, 7, 14, 15, 16, 17.
  • Veronica; wet soil all regions.
• Trumpet Creeper Family: BIGNONIACEAE.
  • Trumpet Creeper (Campsis); 1, 2, 7, 16, 17.
  • Cross-Vine (Bignonia); 1, 2, 17 (Guadalupe River, Victoria Co.).
   

   

  69

  • Catalpa; 1, 2, 16, 17 (widely cultivated).
  • Desert Willow (Chilopsis); 4, 6, 7, 8, 9, 10, 13 westward.
  • Bush Trumpet Flower (Tecoma stans); 8, 10.
• Unicorn Plant Family: MARTYNIACEAE.
  • Unicorn Plant (Martynia) ; 1, 2, 4, 8, 9, 10, 15, 16, 17.
• Broom Rape Family: OROBANCHACEAE.
  • Cancer Root (Anoplanthus) ; 8, 10, 16, 17.
  • Broom Rape (Orobanche); 1, 8, 13, 15, 16, 17.
  • Beech Drops (Epiphagus); 1.
  • Conopholis; 8, 10.
• Bladderwort Family: PINGUICULACEAE.
  • Pinguicula; 1, 2.
  • Bladderwort (Utricularia) ; 1, 2, 3, 4, 5, 6, 7, 9, 13 and eastward.
  • Vesiculina; 1, 2.
• Acanthus Family: ACANTHACEAE.
  • Anisacanthus; 4, 7, 8, 9, 10.
  • Calophanes; 2, 4, 6, 7, 8, 9, 10, 12, 13, 15, 18.
  • Carlowrightia; 8, 10.
  • Croftia; 2, 4.
  • Dianthera; 1, 2, 3, 4, 5, 6, 7, 9, 12, 13, 14, 15, 16, 17, 18.
  • Diapedium; 2, 3, 4, 6, 7, 9, 13, 18.
  • Ruellia; widespread except 8, 10, 11, 12.
  • Siphonoglossa; 4, 7, 8, 9, 10, 13.
  • Stenandrium; 10.
  • Yeatesia; 1, 2.
  • Tubiflora; 2, 4, 9, 10, 13.
  • Hygrophila; 2, 4.
  • Tetramerium; 2, 4.
  • Justicia; 4, 9, 10.
  • Elytraria; 2, 4.
• Lopseed Family: PHRYMACEAE.
  • Lopweed (Phryma); 1, 16, 17.
• Plantain Family: PLANTAGINACEAE.
  • Plantain (Plantago spp.) ; all regions.
• Madder Family: RUBIACEAE.
  • Bouvardia; 8.
  • Button bush (Cephalanthus) ; all regions.
  • Chiococca; 4.
  • Crusea; 2, 4, 6, 7, 14, 15, 16, 17.
  • Diodia; 1, 2, 5, 6, 14, 15, 16, 17.
  • Bedstraw (Galium spp.); all regions.
  • Bluets (Houstonia spp.); all regions.
  • Twinberry (Mitchella) ; 1, 2, 17.
  • Oldenlandia; 2, 1, 16, 17.
   

   

  70

  • The Vegetation of Texas
  • Pentodon; 1, 2, 16, 17.
  • Randia; 4.
  • Richardia; 1, 2, 4, 7, 16, 17.
  • Spermacoce; 2, 4.
  • Borreria; 2, 4.
• Honeysuckle Family: CAPRIFOLEACEAE.
  • Honeysuckle (Lonicera) ; 1, 2, 3, 7, 8, 9, 10, 12, 13, 15, 16, 17, 18.
  • Elder (Sambucus) ; 1, 2, 6, 7, 8, 9, 15, 16, 17, 18.
  • Partridge berry (Symphoricarpus); 1, 3, 8, 15, 16, 17, 18.
  • Black Haw. (Viburnum); 1, 2, 6, 8, 9, 13, 14, 15, 16, 17.
• Valerian Family: VALERIANACEAE.
  • Corn Salad; Lamb's Lettuce (Valerianella); 1, 2, 3, 6, 7, 8, 9, 14, 15, 16, 17.
• Gourd Family: CUCURBITACEAE.
  • Melon Loco (Apodanthera); 4, 10.
  • Gherkin (Cucumis); 4.
  • Gourd (Cucurbita); 4, 6, 7, 9, 10, 12, 13, 14, 15, 18.
  • Bur Cucumber (Cyclanthera); 1, 6, 7, 9, 10, 13, 14, 15, 16, 17.
  • Wild Balsam (Ibervillea); 2, 4, 5, 6, 7, 8, 9, 10, 16, 18.
  • Creeping Cucumber (Melothria) ; 1, 2, 4, 6, 7, 9, 16, 17.
  • Star Cucumber (Sicyos); 1, 2, 4, 6, 7, 9, 16, 17.
• Bell-Flower Family: CAM PANULACEAE.
  • Bell-Flower (Campanula); 6, 8.
  • Lobelia; 1, 2, 4, 7, 8, 10, 12, 13, 16, 17, 18.
  • Venus Looking Glass (Specularia); all regions.
  • Sphenoclea; 2.
• Goodenia Family: BRUNONIACEAE.
  • Scaevola; 2 (Padre Island).
• Ragweed Family: AMBROSIACEAE.
  • Cockle Bur (Xanthium spp.); all regions.
  • Gaertner's Ragweed (Gaertneria); 4, 7, 9, 10, 11, 12, 13, 18.
  • Ragweed (Ambrosia spp.); all regions.
  • Marsh Elder (Iva spp.) ; all regions.
  • Hymenoclea; 7, 9, 10, 11, 13.
• Thistle Family: CARDUACEAE.
  • Ironweed Tribe (VERNONIAE).
  • Elephantopus; 1, 2, 15, 16, 17.
  • Ironweed (Vernonia); widespread; most abundant eastward.
• Thoroughwort Tribe (EUPATORIAE).
  • Brickellia; 8, 10 (4, 9, 7).
  • Carminatia; 8 (Chisos Mts.).
  • Carpochaeta; 8.
  • Coleosanthus; 4, 7, 8, 9, 10, 12, 13, 14, 15, 16.
   

   

  71

  • Benjamin Carroll Tharp
  • Conoclinum; 1, 2, 4, 5, 6, 7, 9, 14, 15, 16, 17, 18.
  • Eupatorium; widespread.
  • Kuhnia; westward from 16.
  • Blazing Star (Laciniaria); all regions.
  • Climbing Thoroughwort (Willugbaeya); 1, 2, 7, 15, 16, 17.
  • Stevia; 8.
  • Trichocoronis; 2, 4, 9, 10.
• Eastern Bromweed (Amphiachyris); westward to 4, 9, 11, 12.
• Aphanostephus; 2, 16 westward.
• Aplopappus; widespread, all regions.
• Aster spp.; all regions.
• Baccharis; all regions.
• Bellis; all regions except perhaps 11, 12.
• Chrysothamnus; 4, 8, 9, 10, 13 westward.
• Boltonia; 1, 2, 16, 17.
• Chaetopappa; 1, 2, 4, 6, 7, 8, 9, 10, 13, 14, 15, 16, 17.
• Chondrophora; 1, 2, 16, 17.
• Chrysoma; 4, 10.
• Chrysopsis; all regions.
• Conyza; 4, 8, 9, 10 (= Eschenbachia).
• Dichaetophora; 4, 9, 10.
• Distosis; 4, 9, 10.
• Fleabane (Erigeron) ; all regions.
• Euthamia; 1, 2, 4, 5, 13, 14, 15, 16, 17, 11.
• Rosin Weed (Grindelia); 16 westward.
• Broomweed (Gutierrezia) ; 15 westward; all regions.
• Gymnosperma; 4, 7, 8, 9, 10, 11, 12, 13.
• Rosin weed (Heterotheca); widespread in sand westward to 10.
• Isocoma; 8, 10.
• Isopappus; 1, 2, 5, 13, 15, 16, 17.
• Keerlia; 2, 5, 6, 7, 9, 15, 17.
• Mare's tail (Leptilon) ; all sandy regions.
• Leucelene; 9, 10, 11, 12, 13.
• Giant Aster (Machaeranthera) ; 7, 9, 10, 11, 12, 13.
• Mauchia; 1, 2, 4, 5, 16, 17.
• Oligoneuron; 1, 2, 17.
• Prionopsis; 2, 12, 13, 14, 15, 16.
• Psilactis; 8.
• Selloa; 4, 8, 10.
• Sideranthus; 2, 4, 5, 8, 9, 10, 11, 12, 13.
• Goldenrod (Solidago spp.) ; all regions.
• Standfieldia; 4, 9, 10.
• Townsendia; 9, 10, 11, 12, 13.
• Thurovia; 2.
• Xanthisma; 5, 6, 7, 9, 11, 12, 13, 14, 15, 16.
 

 

72

• Inula Tribe (INNULACEAE).
  • Antennaria; westward in sand to 15.
  • Calymandra; 2, 4, 6, 7, 14, 15, 16.
  • Chaenolobus; 2, 4, 15, 16.
  • Evax candida; 2, 4, 6, 9, 14, 15.
  • Filago; widespread, all regions.
  • Gnaphalium; all regions.
  • Pluchea; seeps, all regions except 8, 10.
  • Tessaria; 10.
• Sunflower Tribe (HELIANTHEAE).
  • Sea Oxeye (Borrichia); 2, 4, 16 (Gonzales).
  • Berlandiera; 1, 2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,
  • Tickseed (Bidens spp.); all regions. 13, 14, 15, 16, 17.
  • Purple Cone Flower (Brauneria); 1 6, 7, 9, 12,
  • Calyptrocarpus; 4, 7, 16, 18.
  • Clappia; 4.
  • Coreopsis; all regions except perhaps 8, 10.
  • Cosmos; 8, 10. 13, 15, 16, 17.
  • Dracopis; 1, 2, 4, 6, 7, 9,
  • Eclipta; all regions. 13, 18.
  • Encelia; 4, 6, 7, 8, 9, 10,
  • Engelmannia; eastward to 16.
  • Flourensia; eastward to 4, 9, 13.
  • Galinsoga; 8 (Davis Mts.).
  • Gyuznolomia; 4, 8, 10.
  • Sunflower (Helianthus spp.); all regions.
  • Heliopsis; 8.
  • Heterospermum; 8.
  • Isocarpha; 4.
  • Yellow Texas Star (Lindheimera) ; 4, 6, 7, 9, 13, 14, 15, 16, 18.
  • Marshallia; 6, 7, 9, 13, 14, 15, 16, 18.
  • Mountain Daisy (Melanipodium spp.); 6, 7, 8, 9, 10, 12, 13, 18.
  • False ragweed (Parthenium) ; all regions.
  • Polymnia; 7, 16.
  • Ratibida; 2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 18.
  • Rudbeckia; all regions.
  • Sanvitalia; 4, 7, 8, 9, 10, 16.
  • Sclerocarpus; 4, 5, 7, 16.
  • Silphium; westward to 4, 6, 7, 14.
  • Spilanthes; 2.
  • Tetragonotheca; 2, 5, 7, 9, 12, 14, 15, 16, 17.
  • Thelesperma; eastward to 16.
  • Varilla; 4.
  • Verbesina; (all regions).
  • Viguiera; 4, 7, 8, 9, 10, 12, 13, 14, 15, 16, 18.
  • Ximenesia; 4, 6, 7, 9, 10, 11, 13, 14, 15, 16, 17.
  • Zexmenia, 4, 6, 7, 8, 9, 10.
  • Zinnia; 8, 9, 10, 12, 13.
 

 

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• Sneezeweed Tribe (HELENIAE).
  • Actinella; 4, 6, 7, 9, 10, 11, 12, 13, 14.
  • Amblyolepis; 4, 5, 6, 7, 9, 13.
  • Bahia; 4, 9, 10, 13.
  • Baileyi; 8, 9, 10.
  • Boebera; 8 (Guadalupe Mts.).
  • Chrysactinia; 4, 7, 8, 9, 10.
  • Clappia; 4, 9, 10.
  • Dysodia; 2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13.
  • Flaveria; 2, 4, 9, 10, 11, 13.
  • Gaillardia; all regions.
  • Helenium; all regions except 18.
  • Hymenopappus; all regions.
  • Hyrnenoxys; 4, 7, 9, 13 westward.
  • Laphamia; 4, 9, 13 westward.
  • Pectis; 7, 9, 13 westward.
  • Pericome; 8.
  • Perityle; 4, 8, 9, 10.
  • Polypteris; 16 westward in sand or gravel.
  • Porophyllum; 10.
  • Psathyrotes; 10.
  • Psilostrophe; 4, 7, 8, 9, 10, 11, 12.
  • Sartwell-ia; 10.
  • Schkuria; 8.
  • Tagetes; 8.
• ANTHEMIS TRIBE.
  • Achillea; westward to 7, 9, 12.
  • Dog Fennel (Anthemis) ; westward to 16.
  • Sage-brush (Artemisia) ; westward from 16.
  • Soliva; 2 (Corpus Christi), 4 (San Felipe).
• SENECIO TRIBE.
  • Erechtites; 2, 16.
  • Haploesthes; 9, 10, 11, 12, 13.
  • Indian Plantain (Mesadenia) ; westward to 7, 15.
  • Squaw-weed (Senecio); all regions.
  • Bartlettia; 10.
• CYNAREAE TRIBE.
  • Thistle (Carduus spp.) ; all regions.
  • American Star Thistle (Centaurea); 16 westward.
  • Burdock (Arctium) ; no record; probably occurs in cultivated grounds.
• MUTISICEAE TRIBE.
  • Chaptalia; 2.
  • Gochnatia; 4.
  • Perezia; 4, 7, 9, 13 westward.
  • Trixis; 4, 8, 10.
 

 

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• Chicory Family: CICHORIACEAE.
  • Dwarf Dandelion (Adopogon) ; westward to 4, 6, 7, 13.
  • Chicory (Cichorium) ; 6, 7, 13, 14, 15.
  • Crepis; 13.
  • Hieracium; 1, 2, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 17.
  • Prickly Lettuce (Lactuca); all regions.
  • Lygodesmia; 6, 7, 8, 9, 10, 12, 13, 18.
  • Malacothrix; 10.
  • Nicolletia; 10.
  • Pinaropappus; 4, 7, 8, 9, 10, 12, 13, 18.
  • Ptiloria; 8, 9, 10, 13.
  • Serinea; westward to 6, 7, lower 16.
  • False Dandelion (Sitilias); westward to 4, 9, 18.
  • Sowthistle (Sonchus); all regions except 8.
  • Dandelion (Taraxicum); widespread but nowhere abundant; flowers all winter.
  • Tragopogon; 13.

The editors asked Doctor Tharp to define ECOLOGY for them in a few words. This is his answer:

Ecology is the study of the relationship between any organism, plant or animal, and the other organisms which are aggregated together in any community. Among green plants there is usually keen competition for the light, water, air, and mineral salts necessary to sustain their life. All other plants and all animals, including man, are dependent directly or indirectly upon green plants for all their food; and the whole community becomes very complex. In short, the term ecology means the study o f this complex "home life" of an organism.

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TEXAS ACADEMY PUBLICATIONS
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NATURAL HISTORY
Non-technical series Vegetation by B. C. Tharp illustrated $1. Archaeology by J. E. Pearce in preparation Marine Life by C. T. Reed in preparation Indians by M. P. Mayhall in preparation Geology by W. S. Adkins in preparation Climate by R. J. Russell in preparation THE ANSON JONES PRESS403-405 Fannin at Preston Houston Publishers