140 



GRAMINEAE (GRASS FAMILY) 



entire at the acute apex, awnless. {Dupontia Cooleyi Gray ; Graphephorum 

 melicoides, var. major Gray.) — Gravelly or rocky shores, Me,, Vt., Out., and 

 Mich Fig. 121. 



44. DESCHAMPSIA Beauv. 



Spikelets 2 (rarely 3) -flowered ; rhachilla hairy, prolonged behind the upper 

 palea as a hairy bristle ; glumes subequal, thin or scarious ; lemmas thin, 4-nerved 

 (the midnerve becoming an awn), truncate, 2-4-toothed, bear- 

 ing a slender dorsal awn from or below the middle. — Tufted 

 perennials (our species) with flat or involute leaves and shining 

 spikelets in loose or narrow panicles. (Named for Loiseleur- 

 Deslongchamps, a French botanist, 1774-1849.) 



* Glumes somewhat shorter than the florets. 



1. D. flexubsa (L.) Trin. (Common Hair Grass.) Culms 

 erect, 3-8 dm, high, slender, nearly naked above, the numerous 

 involute-setaceous basal leaves 6-20 cm. long ; sheaths scabrous ; 

 blades setaceous; panicle 5-12 cm. long, very loose, rather 

 few-flowered, the smooth capillary flexuous branches spikelet- 

 bearing near the ends ; spikelets 4-5 mm. long ; glumes acute ; 

 florets approximate, lemmas scabrous, ^-toothed, awn inserted 

 near the base, 5-7 mm. long, twisted ; palea nearly as long as 

 the lemma, scabrous. — Dry places, Nfd., Ont., Wise, and 

 northw., s. to N. C. and Tenn, June, July. (Eu.) Fig. 122. 



2. D. caespitbsa (L.) Beauv. Culms erect, 6-12 dm. high, 

 slender ; basal leaves flat or becoming involute, not setaceous, 

 5-15 cm. long; sheaths smooth; blades flat, scabrous on the 

 upper surface ; panicle 10-20 cm. long, the scabrous slender 

 branches spikelet-bearing near the ends ; spikelets 4 mm. long ; 



glumes acute or blunt; florets distant {rhachilla half the length of lower sessile 

 floret) ; lemmas smooth, erose-truncate ; awn from near the base, but little 

 longer than its lemma, straight, articulated at the base and 

 deciduous; palea nearly equaling the lemma. — Moist soil, 

 mostly along streams, Nfd. to Alaska, s. to N. J. and 111. 

 June, July. (Eu.) — Spikelets rarely 3-flowered. Fig. 123. 



122. D. flexuosa. 

 Part of panicle x %. 

 Spikelet and floret 



x2y2. 



* * Glumes longer than the florets. 



3. D. atropurpurea (Wahlenb.) Scheele. Culms erect, 

 1.5-5 dm. high, slender, leafy ; no tufts of basal leaves ; sheaths 123. D. caespitosa. 

 smooth ; blades flat, 5-10 cm. long, 3-5 mm. wide, nearly Spikelet x 31/2. 

 glabrous ; panicle 4-10 cm. long, rather few-flowered ; the few 

 smooth capillary flexuous branches spreading, sometimes drooping, spikelet- 

 bearing at the ends ; spikelets 5-6 mm. long ; glumes acuminate; florets rather 

 distant ; lemmas strigose near the summit, erose-truncate and short-ciliate at 

 apex ; awn inserted about the middle, bent, 3-4 mm. long ; palea nearly equaling 

 the lemma. — Alpine summits of N. E. and N. Y. to Lab. and northwestTw. 

 July, Aug. (Eurasia.) 



45. AVENA [Toum.] L. Oat 



Spikelets 2-6-flowered ; rhachilla bearded below the florets ; glumes subequal, 

 membranaceous, many-nerved, longer than the lemmas, usually exceeding the 

 uppermost floret ; lemmas indurated except toward the summit, 5-9-nerved, 

 bidentate at the apex, bearing a long dorsal twisted awn (the awn straight or 

 wanting in cultivated forms); grain pubescent at least at the summit, often ad- 

 hering to the lemma and palea. — Annuals or perennials with terminal panicles 

 of large spikelets. (The classical Latin name.) 



