GRASS FAMILY 141 



on the nerves below. Perennials with various habit, the above characters cov- 

 ering the California species. Species aboiit 25, mostly American. (Latin tres, 

 three, and dens, tooth.) 



Inflorescence a naked narrow panicle 1. T. muticus. 



Inflorescence a leafy head or umbel 2. T. pulchellus. 



1. T. muticus Nash. Culms erect, 1 to 2 feet high; blades involute, sca- 

 brous; panicle narrow, 3 to 6 inches long, exserted, the branches short and 

 appressed; spikelets terete, narrow, 4 to 5 lines long; glumes about 2 lines 

 long, 1-nerved, shorter than the spikelets; lemmas pilose on nerves, obtuse, 

 about 2 lines long, entire or slightly emarginate, awnless. 



Dry slopes and gravelly banks, central Sierra Nevada (Silver Mt., Brewer 

 2044), east to Colorado and Texas. 



Eefs. TRIDENS MUTICUS Nash in Small, Fl. Southeast. U. S. 143. 1903. Tricuspis muticus 

 Torr. U. S. Eep. Expl. Miss. Pacif. 4: 156. 1857. 



2. T. pulchellus Hitchc. n. comb. Low and tufted, usually not over 6 inches 

 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 culms, the fascicles also producing 

 the inflorescence ; sheaths striate, papery-margined, pilose at base ; blades in- 

 volute, short, scabrous, sharp-pointed, striate; panicles much reduced, usually 

 not exceeding the blades of the fascicle, consisting of 1 to 5 nearly sessile spike- 

 lets; glumes subequal, broad, acuminate, awn-pointed, 1-nerved, 3 to 4 lines 

 long, and about as long as the spikelet ; lemmas 2 lines long, long-pilose below, 

 cleft about half way, the awn about as long or a little longer than the obtuse 

 lobes 



Mesas and rocky hills in the Mohave and Colorado deserts, east to Utah and 

 Texas, and south into Mexico. 



Locs. Funeral Mts., Coville fy Funston 258; Panamint Canon, Hall $ Chandler 6995; New- 

 berry, Chase 5789; The Needles, Chase 5791; Colorado Desert, Hall 5961, Wilder 1094. 



Refs. TRIDEXS PULCHELLUS Hitchc. Triodia pulchella H.B.K. Nov. Gen. & Sp. 1 : 155. 1816. 

 Tricuspis pulcltclla Torr. U. S. Eep. Expl. Miss. Pacif. 4: 156. 1857; Thurb. in Wats. Bot. Gal. 

 2: 301. 1880. 



49. DISSANTHELIUM Trin. 



Spikelets 2 to 4-flowered, the uppermost reduced to a stipe, arranged in 

 panicles. Glumes narrow, acute, equaling or exceeding the spikelet, the first 

 1-nerved, the second 3-nerved. Lemma broad, awnless, 3-nerved. Species 3, 

 1 in California, the others Mexican and South American. (Greek dissos, double, 

 and anthelios. floret.) 



1. D. calif ornicum Benth. Culms 2 to 3 feet high, smooth ; leaves smooth ; 

 ligule membranaceous, 1 to 3 lines long; blades flat, lax; panicle narrow, loose, 

 6 to 8 inches long, the lower clusters of branches rather remote; glumes some- 

 what unequal, the first about 1 to 1% li nes long; lemmas about l 1 /^ lines long, 

 minutely villous, especially below. 



Known only from California: Tassajara Hot Springs, Elmer 3317; San Cle- 

 .mente Island, Trask 324. The specimens at hand are apparently annual. 



Eefs. DISSANTHELIUM CALIFORNICUM Benth. in Hook. Icon. PI. III. 4: 56. pi. 1375. 1881. 

 Stenochloa calif ornica Nutt. Jour. Acad. Phila. II. 1: 189. 1848, type from Santa Catalina 

 Island, Gambel; Thurb. in Wats. Bot. Cal. 2: 315. 1880. 



50. ERAGROSTIS Host. 



Spikelets 3 to many-flowered, usually strongly compressed, in open or con- 

 tracted panicles. Glumes keeled, much shorter than the spikelets. Lemmas 



