184 



POACEAE 



into mucros beyond the margin or extending into the lobes, the midnerve excurrent as a 

 mucro, or short awn, or as a moderately long awn between the lobes, the lower portion of 

 all the nerves pubescent or villous, or the lateral villous nearly the whole length, or in 

 one of our species glabrous except a slight pubescence at base ; palea broad, 2-nerved, the 

 nerves near the margin, sometimes villous. Erect tufted perennials, rarely rhizomatous 

 or stoloniferous, the blades usually flat, the inflorescence an open or contracted panicle, 

 or a cluster of few-flowered spikes interspersed with leaves. [Greek, three-tooth.] 



Species about 25, mostly in America. Type species, Triodia punge)is R. Br. 



Inflorescence a naked narrow jjanicle. 

 Inflorescence a leafy head or umbel. 



1. T. miiticiis. 



2. T. pulchclhts. 



1. Triodia mutica (Torr.) Scribn. 



Av^^nless Triodia. 



Fig-. 418. 



Triciispis muticus Torr. U. S. Rep. E.xpl. Miss. Pacif. 4: 156. 1857. 



Triodia mutica Scribn. Bull. Torrey Club 10: 30. 1883. 



Tridcns muticus Nash in Small, FI. Southeast. U. S. 143. 1903. 



Culms erect. 30-60 cm. high; blades invohife, scabrous; 

 panicle narrow, 7-15 cm. long, exserted, the branches short 

 and appressed ; spikelets terete, narrow, 8-10 mm. long; 

 glumes about 4 mm. long, 1-nerved, shorter than the 

 spikelets ; lemmas pilose on nerves, obtuse, about 4 mm. 

 long, entire or slightly emarginate, awnless. 



r\ Dry slopes and gravelly banks, central Sierra Nevada (Silver 



-i=^ Mountain, Breiver), east to Colorado and Te.xas. July-Aug. Type 



O locality: New Mexico. 



2. Triodia pulchella H. B. K. 

 Low Triodia. Eig. 419. 



Triodia pulchella H. B. K. Nov. Gen. & Sp. 1 : 155. pi. 



47. 1816. 

 Tricuspis pulcheltus Torr. U. S. Rep. Expl. Miss. Pacif. 



4: 156. 1857. 

 Tridciis pulchcllus Ilitchc. m Jepson, FI. Calif. 1: 141. 



1912. 



Low and tufted, usually not over 15 cm. high; 

 culms slender, scabrous or puberulous, consisting 

 of 1 long internode, bearing at the top a fascicle 

 of leaves, the fascicle finally bending over to the 

 ground, taking root and producing other cuhns. 

 the fascicles also producing the inflorescence; 

 sheatiis striate, papery-margined, pilose at liasc ; 

 blades involute, short, scabrous, sharp-pointed, 

 striate ; panicles much reduced, usually not ex- 

 ceeding the blades of the fascicle, consisting of 

 1-5 nearly sessile spikelets ; glumes subefjual. 

 broad, acuminate, awn-pointed, 1-nerved, 6-8 mvs\. 

 long, about as long as the spikelet ; lemmas 4 mm. 

 long, long-pilose below, cleft about halfway, the 

 awn about as long as or a little longer than the 

 obtuse lobes. 



Mesas and rocky hills in the Mojave and Colorado 

 deserts, east to I'tah and Texas, and south into Mexico. 

 February-May. Type locality: Mexico. 



54. DISSANTHELIUM Trin. Linnaea 10: 305. 1836. 



Spikelets mostly 2-flowered, the florets distant, the rachilla slender, disarticulating 

 above the glumes and between the florets ; glumes nearly equal, acuminate, much longer 

 than the lower floret, mostly longer than all the florets, the first 1-nerved, the second 3- 

 ncrved; lemmas strongly compressed, oval or elliptic, acute, awnless, 3-nerved, the lateral 

 nerves near the margin ; palea somewhat shorter than the lemma. Annual or perennial 

 grasses with flat blades and narrow panicles. [Greek, double-floret.] 



Species 2, one in Mexico and South America, the other in California. Type species, Dissanthelium 

 supiiiuin Trin. 



