884 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
the ligule a ciliate, hairy ring; spikes 4 to 6 or 7, 1.5 cm. long; spikelets 25 to 40, 
about 3 mm. long over all, consisting of a floret and a rudiment; glumes hispid-keeled, 
short-awned, the awn subtended on either side by short, lanceolate-pointed teeth of 
the lamina of the glume, the first 2 mm., the second 3 mm. long; lemma 3.5 to 4 mm. 
long, densely hairy, having 3 equal, hispid awns, with 2 comparatively large, laminar 
teeth between them and a smaller one at either side; palet 3 mm. long, 2-awned and 
4-toothed, bearing a few scattered hairs on the outside of the nerves; caryopsis oval, 
about 1 mm. long or less, rounded or slightly flattened on the back, the ventral sur- 
face nearly covered by thescutellum. (PLATE 73, B, facing p. 382. Fiaures 38, 39.) 
The species is variable, sometimes growing a foot high and sometimes only an inch 
(see plate), its size depending upon the character of the soil and the amount of rain- 
fall. In our Southwestern 
States and in Mexico east 
of the Pacific coast region 
it has two quite distinct 
forms, one with short awns, 
the other with long awns, 
making the spike much 
wider in the latter case. 
The long-awned form very 
closely approaches B. are- 
nosa of the Pacific coast of 
Sonora, but that species 
has still heavier spikes. 
Further study, however, 
may require the inclusion 
of that species here. I do 
not feel warranted at pres- 
ent in making a change 
in the nomenclature, for 
my field experience has 
not brought me in contact 
with the arenosa form. 
Pringle’ s 13626, Schaffner 
183 and 187, Rothrock 352, 
Wooton 398, Bourgeau 667, 
Metcalfe 701, are all typi- 
FI@. 39.—Bouteloua barbata. a, Spikelet; b, c, lemma and palet of — calof this species, although 
first floret; d, ¢, rudimentary second and third florets; , two views showing some variation in 
and cross section of caryopsis. a, Scale 7.5; b-f,scale 15, From Griffiths the length of the awns and 
05. 
in the size of the plants, 
and consequently a decided difference in general aspect. Two specimens, from 
Lower California, Brandegee, San José del Cabo, 1890, and Purpus, Cape Region, are 
doubtfully referred here. 
e 
HERBARIUM SPECIMENS. 
Arizona: Toumey in Seymour’s Grasses 85, Tucson. Hitchcock 3668, Patagonia; 
3489, Tucson. Purpus 8293, Beaver Creek. Blumer 1706, Paradise. Mearns 
1121, San Pedro River near Mexican boundary; 2765, Quitovaquito. Griffiths 
1897, Wilcox; 2009, Benson; 1646, Sulphur Spring Valley; 1524, Tucson; 3400, 
Santa Rita Forest Reserve; 3360, Tucson. Knowlton 194, San Francisco Moun- 
tains; Lemmon 4644; Davidson 41a, Clifton; Griffiths & Thornber 254, Santa Rita 
Mountains. Jones 6063, Buckskin Mountains. Rothrock 352, Cottonwood. 
MacDougal 571, Fort Verde. Leiberg 5922, Grand Canyon at Bright Angel Trail. 
