530 Part IV. Chapter 3. 
The southern part of the Texan prairies receives species from the 
south and southwest. At the north the prairie annual flora of Okla- 
homa and Kansas appears to be largely predominant. These prairie annuals 
form an important factor in the flora especially in the early spring, when there 
is a solid mass. This disappears before the climax of the grass vegetation 
season. — West of the Pecos River there is a vast prairie region traversed 
by many ranges of hills and bluffs and cut up by many arroyos and ravines; 
much of it, however, is simply undulating or nearly level. 
e gramineous vegetation of this prairie consists chiefiy of the following ds Buchlo& 
Be dactyloides (east of the Pecos), Bouteloua oligostachya, B. hirsuta, B. riop 
B. curtipendula (= B. racemosa), Pappophorum Wrightii, Triodia ic) a Hilaria 
mutiea (north), H. cenchroides (south), Aristida purpurea, A. dispersa (= A. fasciculata), Ar 
stritta, A. Schiediana, Muhlenbergia texana, M. era Andropogen saccharoides, A. sco- 
a, Lycurus phleoides, Panicum obtusum, P. leucophoe = P. insulare), P. Halli, Setaria - 
caudata. 
This prairie although apparently level, is seldom entirely free from shrubs, such as: Clema is 
Drummondiü, Acacia filieina (= A. Har et Microrhamnus ericoides, Zizyphus a \ 
Ephedra trifurca, E. antisyphilitica, Larrea me a (= Covillea tridentata), Yucca angustifolia 
(= Y. glauca), Nolina texana, Opuntia a ine: — The summer display of herbs is owing 
to the presence of: Talinum aurantiacum, Calophanes linearis, Linum Berlandieri, L. rigidum, 
llirho& pedata, C. digitata, Sida physocalyx (= $. hastata), S. diffusa, Sphaeralcea hastulata, 
yetaginea capitata, Abronia turbinata, Oxybaphus (Allionia) angustifolius, Cooperia Drummondü, 3 
Frnees retusus, Rhynchosia ER ERERERER andidus, P. multiflorus, Verbena bipinnatihda, 
Chamaesaracha coronopus, Solanum e el eencihe en bee virginica, 
C. dianthifolia, Salvia lanc ER Tetraclea Coulteri, Erio Croton corymbulosus, 
Asclepias Jamesi (= A. latifolia), m longilob us, Galllardia ae: Kid tagetina, 
Gutierrezia eriocarpa, Lygodesmia aphylla, Aster tanacetifolius, Thelesperma gracile. 
A large portion of southeastern Texas included between the coast the 
Rio Grande and the Nueces River is a dry grassy country ') and therefore should 5 
be included with the prairies. Zones of chaparral and small timber traverse 
and break this prairie into detached portions. Such trees as Celtis mississif- 
piensis, Prosopis juliflora, Fraxinus viridis, Acacia Farnesiana, Ulmus ameri- | 
cana fringe the dry forks and beds of streams. One of the prairies is covered 4 
with Zlionurus ciliatus, Aristida Purpurea, Sporobolus eryptandrus, W while near. 5 
the Rio Grande and coast grow Bouteloua texana, Cynodon dactylon, and Boute- = 
loua oligostachya is rarely seen. 
e Grand and Black prairies, lying parallel, with only the narrow sp. 
of lower Cross Timbers between, extend from near Austin north in a br 
strip to the Red River bottoms, a an extensive area over which trees 
and forest species are mainly restricted to narrow stream bottoms. Here 
in the river bottoms in the ai of the coast prairie which extends from E 
ı) Havarv, V.: Report on Flora of western and southern Texas. Proceedings U. S, National 
Museum, 1885: 482—485; also consult Cook, C. F.: Change of Vegetation of the south 1 Bi 
Prairies. Circular 14. U. 5. Bureau of Plant Industry. 
