196 



POACE^. 



d. Panicle spikelike, ra3'3 mostly sessile, first glume 

 4-5 mm. long 21 



d. Panicle racemose or spreading, first glume T-9 

 mm. long 32 



1. A. desmantha Trin. & Eupr. Mem. Acad. St. Petersb. (VI.) 

 7:109 (1849). 



A slender sparingly-branched grass, 30-50 cm. high. Sheaths 

 mostly shorter than the internodes; ligule short ciliate; blades in- 

 volute, setaceous, smooth below, 8-20 cm. long, margins of the 

 blade and sheaths also sometimes ciliate. Panicle simple, few- 

 flowered, 8-15 cm. long, rays scabrous, remote. Empty glumes 

 ciliate, 1-nerved, equal, 2-toothed, 10-13 mm. long, besides short 

 bristles; floral glume about 10 mm. long to the jointed, sej^arate 

 awns, which are equal and horizontally spreading when dry. 



Texas, Reverclion 1057. 



Texas and Indian Territory. 



2. A. tuberculosa Xutt. Gen. 1:57 (1818). 



Culms 2-5 cm. high, branching below, nodes tumid; the inter- 

 nodes mostly naked, as the branches crowd the sheaths away. 



Sheaths smooth, twice as long as tlie 

 i-nternodes, to which they really belong ; 

 ligule a ciliate fringe; leaves of sterile 

 shoots very few and short, those of the 

 culm 2-3 in n^^mber, blades involute, se- 

 taceous, 10-20 cm. long, scabrous above, 

 smooth below. Panicle rigid, open, spar- 

 ingly branched, 10-18 cm. long. Empty 

 glumes brown, 15 17 mm. long, the 

 strong nerves scabrid; first glume 

 shorter, the awned tips 5-10 mm. long; 

 floret nearly 15 mm. long, with a hairy 

 pointed callus at the base, and at the 



apex the three awns are twisted and 

 Fig. 40. — AristicUi tuberculosa. , , , 1 1 i i ,. 



A, spikelet; a, floret; b,ca\- auchylosed or soldered together lor 

 lous bearded base. (Scribner.) ^^i^^^^^ g ^^^^^^^ ^^^^^^ ^j^j^jj^ ^^ maturity, 



the three nearly equal tips become divergent or reflexed for 3-4 cm.. 



