MANUAL OF THE GRASSES OF THE UNITED STATES 



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Figure 552.— Trisetum melicoides. Panicle, 

 X 1; glumes and floret, X 5. (Pringle, Vt.) 



cm tall;, sheaths 

 3 to 7 mm wide; 



2. Trisetum wolfii Vasey. Wolfs trisetum. (Fig. 554.) Culms 

 erect, 50 to 100 cm tall, loosely tufted, sometimes with short rhizomes; 

 sheaths scabrous, rarely the lower pilose; blades flat, scabrous, rarely 

 pilose on the upper surface, 2 to 4 mm 



wide; panicle erect, rather dense but 

 scarcely spikelike, green or pale, some- 

 times a little purplish, 8 to 15 cm long; 

 spikelets 5 to 7 mm long, 2-flowered, 

 sometimes 3-flowered; glumes nearly 

 equal, acuminate, about 5 mm long; 

 lemmas obtusish, scaberulous, 4 to 5 

 mm long, awnless or with a minute 

 awn below the tip, the callus hairs 

 scant, about 0.5 mm long, the rachilla 

 internode about 2 mm long, rather 

 sparingly long- villous. % — Meadows 

 and moist ground, at medium altitudes 

 in the mountains, Montana to Wash- 

 ington, south to New Mexico and 

 California. 



3. Trisetum orthochaetum Hitchc. 

 (Fig. 556.) Culms solitary, erect, slender, 110 

 glabrous; blades flat, scabrous, 8 to 20 cm long, 



panicle slightly nodding, 

 lax, pale, about 18 cm long, 

 the filiform branches loose- 

 ly ascending, naked below, 

 the lower fascicled, as 

 much as 8 cm long; spike- 

 lets short-pediceled, some- 

 what appressed, mostly 3- 

 flowered, 8 to 9 mm long 



excluding awns, the rachilla appressed-silky; 



glumes acuminate, about 6 mm long, the second 



wider; lemmas rounded on the back, minutely 



scaberulous on the upper part, obscurely 



5-nerved, the callus short-pilose, the apex 



acute, erose-toothed, awned about 2 mm below 



the tip, the awn straight or nearly so, exceed- 

 ing the lemma about 3 mm. % — Known 



only from boggy meadows, Lolo Hot Springs, 



Bitterroot Mountains, Mont. 



4. Trisetum cernuum 

 trisetum. (Fig. 557.) Culms rather lax, 60 

 to 120 cm tall; sheaths glabrous to sparsely 

 pilose; blades thin, flat, lax, scabrous, 6 to 12 

 mm wide; panicle open, lax, drooping, 15 to 

 30 cm long, the branches verticillate, filiform, 

 flexuous, spikelet-bearing toward the ends; 

 spikelets 6 to 12 mm long, with usually 3 distant 

 florets, the first longer than the second glume; 



first glume narrow, acuminate, 1 -nerved, 0.5 to 2 mm long, the second 



broad, 3-nerved, 3 to 4 mm long, occasionally reduced; lemma 5 to 6 



Figure 553.— Distribution of 

 Trisetum melicoides. 



Figure 554.— Trisetum wolfii. 

 Panicle, X 1; glumes and 

 floret, X 5. (Swallen 809, 

 Calif.) 



Trin. Nodding 



Figuee 555.— Distribution of 

 Trisetum wolfii. 



