532 
9. B. polystachys (Benth.) Torr, (SiIx-weeks Grama.) Culms 1 to 3 dm, high, 
weak, usually branching at the geniculate lower nodes: leaves flat, 2 to 5 cm, long: 
spikes 4 to & about 2cm. long, sHehtly exceeding the intervals: spikelets 1.5 to 
2.5 mm. long; second empty glume obtuse or subacute, usually mucronate, shorter 
than the floret; floral glume with four short obtuse lobes, the outer lobes narrow, 
awns nearly equal, not more than one-half as long as the glume; palet obtusely 
4-toothed, awns little longer than the teeth; awns of rudiment slightly longer than 
the others; pedicel of rudiment bearing a pilose tuft. (Chondrosium polyslachyum 
Benth.)—River valleys, western Texas to southern California. 
+ + Sterile floret reduced to three naked or slightly wingcd awns, 
++ Floral glume 3-toothed or short awned. 
10. B. eriopoda Torr. (WoOOLLY-STEMMED GRAMA,) Perennial culms 3 to 6 dm. 
high, rigid, often decumbent and rooting at the nodes, lanate especially below: leaves 
Hat or involute, attenuate: spikes 3 to 6, 2 to 5 cm. long, rather loosely flowered: 
spikelets 6 to 7 mum. long; second empty glume acute, twice as long as the first, about 
equaling the floret; floral glume slightly pubescent or nearly smooth, middle awn 
nearly 3mm. long, twice as long as the lateral ones; rudiment with few short hairs 
and three equal awns about 6 min. long.—Dry gravelly plains, western Texas to 
Arizona. 
++ ++ Floral glume distinelly 35-awned, 
ll. B. trifida Thurb. (Grama.) Culms 1 to 8 dim, high, mostly simple, from a 
perennial cespitose base: leaves narrow, hispidulous, mostly at the base: spikes 3 
to 6, rather loosely flowered, about 2 cm. long, exceeding the intervals: spikelets 2.5 
to3 mm, long; second empty glume subobtuse, one-third longer than the first, and 
about equaling the floret; floral glume slightly ciliate on the nerves or nearly smooth; 
-awns 2 to 3 times as long as the glume; palet awnless; sterile pedicel naked, the 
awus equaling those of the perfect tloret.—High mesas, western Texas to Arizona. 
Var. BURKEI (Seribn.) Vasey is generally leafy throughout, with spikelets 3 to 3.5mm. 
long, and floral glume more pubescent than in the type. (B. Burkei Scribn.)—Sandy 
plains, central and southern Texas to New Mexico. 
§ 2. Spikelets not distinetly pectinate, few (5 to 12) in the short thick straight spikes; 
sterile floret sometimes staminate, sometimes reduced to 1 to 3 awns.—ATHEROPOGON, 
“Empty glumes woolly pubescent. 
12, B. Havardii Vasey. (WOOLLY-SPIKED GRAMA.) Culms 2 to6dm. high, simple 
from a tufted perennial base: leaves mostly from the base, flat, rather thick, 1 to 2 
din. long; spikes 4 to 8, 1 to 2 cm, long at intervals of about their own length on the 
flat axis: spikelets 6 mm. long, pubescent throughout; second empty glume three 
times as long as the first, nearly equaling the floret; floral glume 3-toothed, awnless; 
awns of rudiment nearly equal, 5 to 10mm, long, the middle one wing-margined; 
pedicel naked.—High gravelly plains, western Texas to Arizona. 
“= Empty glumes glabrous except the hispidulous keel, 
+ Sterile floret staminate, with an obscure pedicel-like rudiment of a third flore 
13. B. bromoides (HBK.) Lag. (?) (Large Mesquir.) Culms 2 to 6 dm. high, 
often branching: leaves flat, narrow, smooth or ciliate margined: spikes 5 to 10, 
subsecund, 1 to 2 cm. long, exceeding the intervals: spikelets 6 to 8 mm. long; 
second empty glume boat-shaped, nearly equaling the floret; floral glume smooth 
except on the three short awl-pointed teeth, the middle one longer than the 
lateral ones; glume of staminate floret awned midway on the margins and with a 
membranaceous tooth each side of the base of the middle awn; palet equaling the 
glume; pedicel naked or slightly bearded. (Dinebra bromoides HBK.)—Western 
