GRASS FAMILY 141 



on tlie nerves below. Pereuuials with various habit, the above characters r-ov- 

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

 three, and dens, tooth.) 



Inflorescence a naked narrow panicle 1. T. muticus. 



Inrtorescenee a leafy head or umbel 2. T. pulclielhis. 



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

 brous; panicle narrow, '-^ to 6 inclics lont?. exserted, the branches short and 

 appressed; spikelets terete, narrow, ■! 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, 



Refs, — Tridens muticus Nash in Small, Fl. Southeast. U. S. 143. 190.3. Tricuspis miitirus 

 Torr. II. S. Rep. Expl. Miss, Pacif. 4: 156. 1S.57. 



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

 high ; culms slender, scabrous or puberulous, consisting of 1 long iutei-node, 

 bearing at the top a fascicle of leaves, the fascicle finally bending over to the 

 groiuul, taking root and produc-ing other cidms, the fascicles also producing 

 the intlore.scence ; 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 nearlj- 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 tlian the obtuse 

 lobes. 



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

 Texas, and south into JMexico. 



Logs. — Funeral Mts., Coville 4~ Funston 25S; Panamint Cafion, Hall ij- Chandler 6995; New- 

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



Refs. — Tridens pulchellus Hitchc. Triodia pidchella H.B.K. Nov. Gen. & Sp. 1: 155. 1816. 

 Trie-uspis pulchclla Torr. U. S. Rep. Expl. Miss. Pacif. 4: 15(). 1857; Thurb. in AVats. Bot. Cal. 

 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. Culnis 2 to 3 feet high, smooth : leaves smooth ; 

 ligule membranaceous, 1 to :i 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 11/2 lines long; lemmas about 1'^ lines long, 

 minutely villous, especially below. 



Known only from California: Ta.ssa.iara Hot Springs, Elniir 3317; San Cle- 

 niente Island, 7'rasJ; 324. The specimens at hand are apparently annual. 



Refs. — DissANTHELiUM CALiFORXicuM Bcnth. in Hook. Icon. PI. III. 4: 56. pi. 1375. 1881. 

 SUiiochloa calif ornica Nutt. Jour. .\cad. Pbila. II. 1: 189. 1848, type from Santa Catalina 

 Island, Gamhel; Thurb. in Wats. Bot. Cal. 2: 315. 18S0. 



;-)(). ERAGROSTIS Host. 

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

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



