(GRASS FAMILY.) 417 



2. Spikes numerous, usually short, straight, not pectinate, in a long and virgate 



one-sided spike or raceme : terminal empty glume rudimentary. 

 5. B. racemosa, Lag. Stems tufted, 1 to 3 feet high : leaves narrow : 

 spikes inch long or shorter, nearly sessile, 30 to 60 in number in a loose 

 general spike (8 to 15 inches long) : sterile glume reduced to a single small 

 awn, or mostly to 3 awns shorter than the flower. B. curtipendula, Torr- 

 From Colorado and Arizona to Texas and northeastward. 



29. BITCH LOB, Engelm. BUFFALO GRASS. 



A densely tufted grass, forming broad mats and spreading by stolons : 

 stems of the female plant much shorter than those of the male. The two 

 forms, at first described as different genera, were shown to be related by Dr. 

 Engelmaun. 



1. B. dactyloides, Engelm. Flowering stems of the male plant 4 to 

 6 inches long, glabrous or slightly hairy : leaves 2 to 4 inches long : spikelets 

 alternate in 2 rows, uppermost abortive, bristle-form : stems of the female 

 plant much shorter than the leaves, l to 2 inches high. Trans. St. Louis 

 Acad. i. 432. On the elevated plains from British America to Texas and 

 New Mexico. One of the many " Buffalo Grasses/' but probably one of the 

 most widely distributed and valuable grasses of the plains. 



30. TRIODIA, R. Br. 



Stems tufted: leaves very narrow and taper-pointed; sheaths bearded 

 at the throat : panicle simple or compound ; spikelets often racemose, 

 purplish. 



1. T. mutica, Benth. Stem rigid, erect, very simple, a foot high: leaves 

 convolute-filiform, 3 to 6 inches long: panicle much exserted, racemose, with 

 short appressed branches; spikelets 5 to 8 -flowered: outer glumes rather acute, 

 scarcely half the length of the florets : flowering glume aumless, entire or bifid, 

 long-ciliate on the margin and back. Tricuspis mutica, Torr. Bot. Whipple, 

 156. From Texas to Arizona, and extending into S. Colorado. 



2. T. pulchella, HBK. Stems crowded, wiry, 2 to 6 inches high, fas- 

 cicdately branched above : leaves setaceously convolute, rigid, scabrous; radical 

 leaves crowded, an inch long ; upper leaves shorter, the uppermost even appear- 

 ing like large awned glumes: panicle of about 3 spikelets, 6 to 1 -flowered : 

 outer glumes white, acuminate or subulate-pointed, the upper slightly exceeding 

 the lower and the florets : flowering glume white, densely silk y-v ill ous to near 

 the middle, deeply bifid, with a strong awn slightly exceeding the obtuse lobes. 

 Tricuspis pulchella, Torr. Pacif. R. Rep. iv. 156. From W. Texas to 

 S. Colorado, Utah, Arizona, and S. California. 



3. T. acuminata, Benth. Stems simple, 6 inches or more high, usually 

 with but a single node, which bears a very short leaf : radical leaves an inch 

 or two long; those of the stem shorter: panicle dense, ovoid, 1 to 2 inches 

 long, with a few erect branches; spikelets 8 to 12-flowered : outer glumes 

 acuminate, the upper subaristate : flowering glume scarcely bifld, with a central 

 seta J its length, densely silky below, with a conspicuously silky tuft near the 



27 



