528 Part IV. Chapter 3. 
Scarcely have these forms flowered before the third week of June when there appear Anemone 
cylindrica, Physalis heterophylla, Verbena strieta, Linum sulcatum, Allionia littoralis, Festuca 
octoflora and Aristida purpurea. 
rein aspect, perhaps the most distinet of the aspects, is introduced in early 
July by . general flowering of Agropyron oceidentale (= A. Smithii), Buchlo& (Bulbilis) dac- 
nn Petalostemon en purpurea and K. (P.) candida. 
acies is composed of Bouteloua oligostachya, B. hirsuta, B. curtipendula (= racemosa), 
ie dactyloides with Zr primary species as Petalostemon purpurea, Verbena strieta, Symphori- 
carpus oceidentalis, Amorpha canescens. — The autumnal aspect begins in early August by the 
blooming of Helianthus scaberrimus, Solidago rigida, the bunch grasses Andropogon furcatus and 
A. scoparius. It exends into early October. Its floral activity is terminated, however, by the 
middle of September by the anthesis of Gentiana puberula and Solidago rigidiuscula. 
Buffalo Grass Formation. Buffalo grass Buchloe (Bulbilis) dactyloides*) and 
grama grass Bouteloua oligostachya are the sole facies. The dense mats of 
the former are peculiarly exclusive. Other grasses are never abundant, and 
are to be found only in the intervals between the mats of the buffalo-grass. 
Bouteloua curtipendula and B. oligostachya are the most common, while Aris- 
tida purpurea, Agropyron pseudorepens, Distichlis spicata var. stricta and 
Koeleria cristata are the remaining grasses. Asclepias pumila, Verbena bipin- 
natifida are characteristic while Amorpha canessens, Petalostemon candidus, 
Solidago missouriensis are common and Yucca ira [= : glauca), 
Ipomoea leptophylla, Psoralea esculenta, Dalea aurea are infreque 
The area of Buchloe is large, but greatly interrupted. The ser Estacado 
(Staked Plain) of Texas, a tableland about 4000 feet above sea level, is covered 
with a buffalo-grass sod. Under different names it is continued north to the 
Black Hills of Dakota as a treeless plain, in many parts not even a native 
cottonwood (Populus monilifera) being found along the streams for hundreds 
of miles. This is the true "Great American Desert” of early writers. 
That covered by Bonteloua oligostachya and Andropogon scoparius is more 
extensive. The fullest development of this formation is in the Dakotas and 
eastern Montana from which it extends southward through Nebraska and Kansas. 
The prairie, or range, as it is called in western South Dakota, is tenanted by 
such characteristic species as: Stipa comata, Bouteloua hirsuta, B. oligostachya, 
B. curtipendula = B. racemosa), Agropyron glaucum, A. repens, Yucca, Sophora 
sericea, Schrankia, Psoralea, Astragalus crassicarpus (= A. caryocarpus), 
A. PR. Gutierrezia, Solidago missouriensis, S. canadensis, S. serolina, 
Helianthus petiolaris?). The Buchlo&-prairie type exists on the argillaceous 
tablelands, the Bouteloua type is found over sandy stretches, thus offering a 
transition to the sand-hill flora. 
e southern extension of the North American prairies is to be found 
in Texas which has a climate that may appropriately be called “a grass - 
plains climate”, and the grasses may be said to form the foundation element 
I) SCHAFFNER, JOHN H.: The re of Buffallo Grass. The Botanical Gazette XXVII: 393: 
2) WırLıams, T. A.: :Notes on the Flora of western South Dakota. American Naturalist, 
XXVI (1892); 256, 
FEN 
