GRASS FAMILY 



167 



36. TRISETUM Pers. Syn. PI. 1 : 97. 1805. 



Spikelets 2-flowered, sometimes 3-5-flo\vered, the usually villous rachilla disarticulat- 

 ing above the glumes and between the florets, prolonged behind the upper floret; glumes 

 somewhat unequal, acute, awnless, the second usually longer than the first floret; lemmas 

 usually short-bearded at the base, 2-cleft at the apex, the teeth often awned, a straight 

 and included, but usually bent and exserted awn from the back below the apex. Tufted 

 perennials with flat blade- and open or usually contracted or spikelike panicles. [Latin, 



three bristles.] 



Species about 65 in the arctic and temperate regions of the world. Type sjiecies, Tri'setum flavesceus L. 



Awn included or wanting. 



Awn exserted. 



Panicle loose and open, the branches naked at base. 

 Panicle narrow or compact. 



Panicle narrow but loose; blades flat, usually 5-10 mm. wide. 

 Panicle spikelike. 



Sheaths pubescent. 4. T. s}^icatum. 



Sheaths glabrous. 5. T. sescimliontm. 



1. Trisetum wolfii Vasey. 

 Beardless Trisetum. Fig. 2)77 . 



Trisetum wolfii Vasey, U. S. Dept. Agr. Month. Rep. Mar. 



156. 1874. 

 Trisetum siibspicatum mnticnm Boland.; S. Wats. Bot. Calif. 



2: 296. 1880. 

 Trisetum brandegei Scribn. Bull. Torrey Club 10: 64. 1883. 

 Trisetum muticum Scribn. U. S. Dept. Agr. Div. Agrost Bull. 



11: 50. /. 10. 1898. 

 Trisetum wolfii muticum Scribn. Rhodora 8: 88. 1906. 



Culms smooth, erect, 30-60 cm. tall ; sheaths smooth 

 or sparsely retrorse-pilose ; blades flat, erect, 2-4 mm. 

 wide, scabrous or more or less pilose ; panicle narrow, 

 usually spikelike, 5-10 cm. long ; glumes about 6 mm. 

 long, scabrous on the keel, subequal, the first 1-nerved 

 or obscurely 3-nerved, the second 3-nerved ; lemmas 

 scaberulous, the lower 4 mm. long, the awn reduced 

 to a bristle scarcely reaching the tip, or on the upper 

 lemma obsolete, the teeth acute, not aristate. 



Mountain meadows, Washington (Spangle) to Colorado, 

 and south in the Sierra Nevada to Sequoia National Park. 

 July-Aug. Type locality: Twin Lakes, Colorado. 



2. Trisetum cernuum Trin. 



Nodding Trisetum. 



Fig. 



378. 



Trisetum eemuum Trin. Mem. Acad. St. Petersb. VI. Math. 



Phys. Nat. 1: 61. (Jan.) 1830. 

 Avena nutkacnsis Presl, Rel. Haenk. 1: 254. 1830. 

 Trisetum sandbergii Beal. Grasses N. Am. 2: 378. 1896. 

 Trisetum nutkaense Scribn. & Merr. ; Davy, Univ. Calif. Publ. 



Bot. 63. 1902. 



Culms rather lax, 60-120 cm. tall ; sheaths smooth ; 

 blades thin, flat, lax, scabrous, 6-12 mm. wide ; panicle 

 open, lax or drooping, 15-30 cm. long, the branches 

 verticillate. slender, flexuous, spikelet-bearing toward 

 the ends ; spikelet 6-12 mm. long, with usually 3 distant 

 florets, the first longer than the second glume ; glumes 

 very unequal, the first narrow, acuminate, 1-nerved, 1 

 mm. long, the second broad, 3-nerved, 3-4 mm. long; 

 lemmas with setaceous teeth, the awns about as in T. 

 canescens. 



Moist woods in the Transition Zone; Alaska to Montana and 

 south in western California to Mendocino County. July-Aug. 

 Type locality: Sitka. 



