No. 34. 
BOUTELOUA. 
The genus Bouteloua, which includes those grasses popularly called grama grass, 
is a very large one in the Southwest, embracing many species, both annuals and 
perennials. They are nearly all nutritious and valuable for pasturage. The gen- 
eral characters of the inflorescence are as follows: 1 or several-flowered spikes 
single at the apex of the culm, or several disposed in a raceme; these spikes 
closely crowded or loosely imbricated with spikelets arranged ‘ah one side of 
the rachis in 2 rows; spikelets usually consisting of 1 perfect flower and a ° 
pedicel (bearing 1 to 3 stiff awns, and usually a few imperfect glumes with the 
awns) ; one or two additional imperfect flowers rarely present in the spikelet ; 
flowering glumes variously lobed at the apex, lobes terminating with awns. The 
several species present a great diversity in the details of these general features. 
« 
BOUTELOUA ARENOSA Vasey. 
Plant annual. Roots few, fibrous. 
Culms in tufts, erect or decumbent, simple or geniculate and branching below 
slender, 6 to 10 inches long. 
Leaves sparse; sheath loose, shorter than the internode, striate ; ligule conspicu- 
ous, strongly ciliate; blade $ to 1 line wide, 1 to 2 inches long, long-acuminate. 
Panicle 2 to 24 inches long, composed of 3 or 4, mostly one-sided sessile 
spikes, 4 to # inches long, erect, or somewhat recurved, consisting of about 20 
spikelets arranged alternately on the narrow flattened rachis. 
Spikelets imbricated, each with 1 perfect and 1 rudimentary flower, about 
3 lines long including the awns. 
Empty glumes thin, smooth, 1-nerved, oblong-lanceolate, 1 to 14 lines long, 
upper usually the longer, both acute and sometimes toothed at the apex and ter- 
minated with a short awn; flowering glume woolly externally, dividing into 2 
lateral and 1 central awn, body about 1 line long, extending into 2 narrow 
teeth or lobes rather shorter than the awns, lateral awns nearly 2 lines long, cen- 
tral one somewhat shorter. 
Palet narrower than its glume, 2- to 4-toothed, 2-nerved, nerves extended into 
awns. Imperfect flower inclosed by the flowering glume, consisting of 3 long 
awns at the summit of a short hairy pedicel, 2 of the awns having each a rudi- 
mentary scale at the base. 
PLATE XXXIV; a, oma enlarged ; b, empty glumes; c¢, flowering glume; 
d, palet ; e, imperfect flower 
The specimens were from loose sandy soil, at Guaymas on the Gulf of California. 
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