GRASS FAMILY 29 



31. CALAMAGROSTIS Adans. Reed-grass. 



Awn of the lemma geniculate, exserted; caUus-halrs usually much shorter than the glume. 

 Awns of the lemma greatly exceeding the empty glumes; plant tufted; leaf-blades 

 involute. 

 Empty glumes very scabrous throughout; marcescent basal leaf-sheaths very 

 long, loose and numerous. 1. C. purpurascens. 



Empty glumes nearly glabrous, except on the keels; marcescent basal leaf-sheaths 

 short and few. 2. C. Vaseyi. 



Awns of the lemma about equalling the empty glumes. 



Empty glumes sharply keeled; spikelets strongly compressed; plant stoloniferous. 



3. C. montanensis. 

 Empty glumes riot strongly keeled; spikelets not strongly conpressed; plants 

 tufted. 

 Leaves usually involute; panicle very dense. 



Panicle very narrow, spike-Uke, usually red-purpUsh. 4. C. rubescens. 

 Panicle lance-oblong, u.sually pale green. 5. C. Suksdorfii. 



Leaves usually flat; panicle ovoid, open. 6. C. luxurians. 



Awn of the lemma straight or nearly so, included; callus-hairs usually equalling the 

 lemma (except in C. scopulorum and C. Cusickii). 

 Panicle open, the lower branches spreading; leaf-blades usually flat; callus-hairs 

 nearly or quite equaUing the lemma. 

 Empty glumes 4-6 mm. long, narrow, sharp-acuminate; awn of the lemma at- 

 tached below the middle, exceeding the lemma. 7. C. Langsdorfti- 

 Empty glumes 2-4 mm. long; awn of the lemma aotached at or above the middle, 

 shorter than the lemma. 

 Awn attached near the middle of the lemma; spikelets usually purple. 

 Spikelets 3-4 mm. long : panicle loosely flowered. 8. C. canadensis. 

 Spikelets 2-2.5 mm. long; panicle densely flowered. 9. C. Macouniana. 

 Awn attached near the apex of the lemma; spikelets pale or white. 



10. C. blanda. 

 Panicle more or less contracted. 

 Leaf-blades flat or nearly so. 



Empty glumes smooth or nearly so, except on the veins. 



Callus-hairs copious, at least two-thirds as long as the lemma; plant with 



a rootstock. 11. C. Scribneri. 



Callus-hairs sparse, much shorter than the lemma. 



Plant tall, 9-12 dm. high; sheaths bearded at the summit; plant with a 



rootstock. 12. C Cusickii. 



Plant lower, 3-8 dm. high; sheaths not bearded; plant tufted. 



13. C. scopulorum. 

 Empty glumes verj scabrous; plant tufted. 14. C. elongata. 



Leaf-blades strongly involute. 



Panicle open. 15. C. lucida. 



Panicle dense, narrow, spike-like. 



Spikelets 2 mm. long; empty glumes thickish, barely acute or obtusish. 



16. C. micrantha. 

 Spikelets 3— 1.5 mm. long. 



Plant scarcely cespitose; empty glumes long-acuminate. 



Leaves fiUform, soft; plant 4-6 dm. high, slender; empty glumes 



minutely scabrous on the veins. 17. C. neglecta. 



Leaves stifl! and hard; plant 8-12 dm. high; empty glumes strongly 

 scabrous. 18. C. inexpansa. 



Plant densely cespitose; empty glumes abruptly acute or short-acumin- 

 ate, very scabrous. 19. C. americana. 



32. CALAMOVILFA Hack. Reed-grass, Sand-grass. i. C. longifoUa. 



33. DESCHAMPSIA Beauv. Hair-grass. 



Empty glumes not extending beyond the apex of the upper lemma; lower empty glume 

 1-nerved ; densely cespitose tufted perennials. 

 Leaves neither stiff nor pungent. . , , , , , ,. 



Awn inserted one-third to one-fifth from the base of the lemma; branches of the 

 inflorescence at last spreading or reflexed. 

 Awns long-exserted, at least half longer than the lemma. 



Empty glumes 3— i mm. long; leaves flUform, revolute, scarcely 1 mm. 



wide; plant 2-3 dm. high. 1- D- curtifoha. 



Empty glumes 4-5 mm. long; leaves broader and often flat, 1.5-2.5 mm. 

 wide; plant 3-5 dm. high. 2. D. alpicola. 



Awns scarcely exserted beyond the lemma. 3. D. caespitosa. 



Awn inserted near the base of the lemma, slightly if at all exceedmg it; branches 

 of the inflorescence ascending. 4. D. confims. 



Leaves arcuate, strongly Involute, very stiff and pimgent. 5. D. pungens. 



Empty glumes extending beyond the apex of the upper lemma. ^ 4. - „ , 



Spikelets usuaUy dark purple; empty glumes lanceolate, purple, about 5 mm. long, 

 the lower 1-nerved. ,. , , * „ t„ q QD. atropurpurea. 



Spikelets light green; empty glumes Imear-lanceolate, both 3-nervea. 

 Spikelets 3-5 mm. long; tufted perennials. ., , ^ „ ^ 



Leavas flllform-involute; sheaths close; spikelets 3-4 mm. long. 



7. D. elongata. 

 Leaves involute but not filiform, or the stem-leaves flat; upper sheaths loose; 

 spikelets 4-5 mm. long. 8. D. ciltaia. 



Spikelets 5-8 mm. long; annuals. 9. u. caiycma. 



