60 POACEAE 



branches; empty sliimes 3-4 mm. long, 3-nerved, green; lemma about 2 mm. 

 long, irregularly 5-toothed at the ajjex; awn inserted near the base, almost 

 twice as long as the lemma. Wet places: B.C. — Calif. — Ariz. — Wyo. — Mont.; 

 Mex. Submont. Je-Au, 



8. D. ciliata (Vasey) Rydb. Stem 4-7 dm. high, com])aratively stiff; leaf- 

 blades 1-2 dm. long, about 2 nun. wide; panicle elongated, with nearly erect 

 branches; empty glumes minutely scabrous; lemma 3 mm. long, erose-dentate 

 at the apex; awn attached a little below the middle, 2-3 times as long as the 

 lemma. D. clongaia ciliala Va.sev. Wet places: B.C. — Calif. — Ida. Submont. 

 ]\Iy-JI. 



9. D. calycina Presl. Annual, simple or branched at the base; stems 1-4 

 dm. high; leaf-blades 1-10 cm. long, filiform; inflorescence ovoid, 3-20 cm. long, 

 with ascending branches; spikelets usually purplish; emjity glumes linear-lance- 

 olate, acuminate, 3-nerved; lemma 3 nnii. long, 3-toothed at the apex; awn 

 attached near the middle, about 3 times as long as the lemma. Wet places: 

 Yukon — B.C. — Ida. — Ariz. — Calif. Submont. My-Jl. 



34. TRISETUM Pers. False Oat. 



Annual or perennial tufted grasses, with flat leaf-blades. Inflorescence a 

 spike-like contracted or open panicle. Spikelets usually 2-flowered, rarely 3-6- 

 fiowered, the flowers perfect, or the upper one staminate. Empty glumes mem- 

 branous, unequal, acute, entire at the apex, awnless, persistent. Lemma 2- 

 toothed at the apex, the teeth acuminate and often terminating in a bristle or 

 slender awn; awn often twisted, inserted below the apex and arising between 

 the teeth. Palet hyaline, 2-toothed. Styles distinct; stigmas plumose. 



Inflorescence lanceolate, open; lower empty glume shorter than and scarcely more than 



half as broad as the upper; leaf-blades broader than the sheaths and therefore 



with auricles at the base. 



Lemma about 7 mm. long; sheaths hairy. 1. T. canescens. 



Lemma about 5 mm. long; sheaths glabrous. 



Ovary pubescent at the apex; panicle loose; its branches spikelet-bearing above 



the middle. 2. T. cerniturn. 



Ovary glabrous; panicle denser; its branches spikelet-bearing to the base. 



3. T. montanum. 

 Inflorescence dense, oblong or oblong-lanceolate; lower empty glume nearly as broad as 



the upper; leaf-blades not liroader than the sheaths, not auricled. 

 Leaf-sheaths and blades long-hairy ; upper part of the stem densely pubescent. 



4. T. subspicatum. 

 Leaf-sheaths and blades glabrous or the lowest sheath short-pubescent, with refle.xed 



hairs; stem glabrous or slightly scabrous in the inflorescence. 5. 3 . majus. 



1. T. canescens Buckl. Perennial, with a rootstock, more or less cesjiitose; 

 stem 5-10 dm. high; leaf-blades 1-1.5 cm. long, about 5 mm. wide; panicle 1.5-3 

 dm. long, narrow; branches spikelet-bearing to near the base; spikelets 2-3- 

 flowered; awn about twice as long as the lemma. Open woods and hillsides: 

 B.C. — Mont. — Cahf. Submont. Je-Au. 



2. T. cernuum (Kunth) Trin. Perennial, with a rootstock; stem 6-10 dm. 

 high; leaves glabrous; blades 1-2 dm. long, .5-7 mm. wide; panicle 1-2.5 dm. 

 long, open and nodding; spikelets 2-3-flowered; lemma about 6 mm. long, slightly 

 scabrous above; awn twice as long as the lemma. Stream-banks: Alaska — Ida. — 

 Calif. Submont. Je-S. 



3. T. montanum Vasey. Perennial, with a rootstock; stem 4-10 dm. high, 

 glabrous; leaf-blades glabrous, 1.5-2.5 dm. long, 3-5 nun. broad; panicle 1-2 dm. 

 long, with ascendinp' branches; spikelets about 5 mm. long; upper glume 4 mm. 

 long, broadly lanceolate; lemma about 4 mm. long; awn about twice as long as 

 the lemma. Moist places among bushes: Wyo. — N.M. — Utah. Submont. — ■ 

 Mont. Jl-S. 



4. T. subspicatum (L.) Beauv. Cespitose perennial; stems 2-4 dm. high; 

 leaf-blades 3-15 cm. long,- 2-3 mm. wide, flat or in age involute; panicle oblong, 

 often obtuse, usually more or less purple, 2-8 cm. long; empty glumes lanceolate, 

 acuminate or acute, slightly shorter than the lemma; awn bent and twisted, 

 7-8 mm. long. T. subspicatum molle A.Gray. T. .'spicatum (L.) Richter. Mead- 



