MANUAL OF THE GRASSES OF THE UNITED STATES 307 



lb. Awn included or scarcely longer than the glumes, straight or geniculate. 

 3a. Awn geniculate, protruding sidewise from the glumes; callus hairs rather 

 sparse, shorter than the lemma. (See C. cainii, p. 993) 

 Blades narrow, soon involute; plants low, usually less than 30 cm tall, not 

 tufted, rhizomatous. Panicle compact, spikelike _ 7. C. moxtaxexsis. 

 Blades flat, drying involute at tip; plants usually tall. 

 Sheaths pubescent on the collar. 



Callus hairs about one-third as long as lemma; western species. 



8. C. RUBESCEXS. 



Callus hairs half to three-fourths as long as lemma; eastern species. 



Palea about as long as the lemma 9. C. porteri. 



Palea three-fourths as long as the lemma 10. C. perplexa. 



Sheaths glabrous on the collar. 



Panicle loose, the branches spreading or ascending. Plants 1 to 1.5 m 



tall; blades as much as 1 cm wide 11. C. xutkaexsis. 



Panicle compact. 



Culms stout, mostly more than 1 m tall 12. C. densa. 



Culms more slender, mostly less than 1 m tall. 



Spikelets 5 mm long; lemma as long as the glumes; panicle spike- 

 like 13. C. KOELERIOIDES. 



Spikelets about 4 mm long; lemma shorter than the glumes; panicle 

 scarcely spikelike, some of the branches naked below. 



14. C. PICKERIXGII. 



3b. Awn straight (somewhat bent in C. epigeios and C. lactea), included; callus 

 hairs usually not much shorter than the lemma. 

 Sheaths pubescent on the collar (see also C. inexpansa var. barbulata) . 



15. C. SCRIBXERI. 



Sheaths glabrous on the collar. 

 Panicle rather loose and open. 



Callus hairs copious, about as long as the lemma; awn delicate, 

 straight 16. C. canadensis. 



Callus hairs rather scant, about half as long as the lemma; awn 



stronger, weakly geniculate 17. C. lactea. 



Panicle more or less contracted. 

 Blades flat, rather lax. 



Awn attached near the base; rachilla not prolonged. 



23. C. epigeios. 

 Awn attached at or about middle; rachilla prolonged. 



Glumes scabrous; plant green 18. C. cixxoides. 



Glumes nearly smooth; plant pale 19. C. scopulorum. 



Blades involute or, if flat, rigid and becoming involute. 



Blades broad and short, as much as 5 mm wide, nearly smooth. 



22. C. CRASSIGLUMIS. 



Blades elongate, smooth or scabrous. 



Blades firm, scabrous, rather rigid; ligule 4 to 6 mm long; 



panicle firm 20. C. ixexpaxsa. 



Blades rather lax, narrow; ligule 1 to 3 mm long; panicle rather 



soft 21. C. XEGLECTA. 



1. Calamagrostis bolanderi Thurb. (Fig. 609.) Culms erect, 1 to 

 1.5 m tall, with slender rhizomes; sheaths scabrous; ligule 4 to 5 mm 

 long; blades flat, 5 to 9 mm wide, scattered, nearly smooth; panicle 

 open, 10 to 20 cm long, the branches verticillate, spreading, naked 

 below, the longer 5 to 10 cm long; glumes 3 to 4 mm long, purple, 

 scabrous, acute; lemma very scabrous, about as long as the glumes, 

 the awn from near the base, geniculate, exserted, about 2 mm long 

 above the bend, the callus hairs short; rachilla pilose, 1 to 2 mm long. 

 % — Bogs and moist ground, prairie or open woods, near the coast, 

 Mendocino and Humboldt Counties, Calif. 



2. Calamagrostis howellii Vasey. (Fig. 610.) Culms densely 

 tufted, rather slender, ascending, 30 to 60 cm tall; sheaths smooth or 

 slightly scabrous; ligule 2 to 8 mm long; blades slender, scabrous on the 

 upper surface, flat or soon involute, especially toward the tip, about 

 as long as the culms, the two cauline shorter, about 1 mm wide; 



