140 



GRAMINEAE (GRASS FAMILY) 



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

 melicoides, var. major Gray.) Gravelly or rocky shores, Me., Vt., Ont., 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, 4-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. 



* * Glumes longer than the florets. 



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

 1.6-5 dm. high, slender, leafy ; no tufts of basal leaves ; sheaths 128. D. caespitosa. 

 smooth ; blades flat, 6-10 cm. long, 3-5 mm. wide, nearly Spikelet x 3%. 

 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 aiid 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 northwestw. 

 July, Aug. (Eurasia.) 



122. D. flexuosa. 

 Part of panicle x %. 

 Spikelet and floret 



45. AVENA [Tourn.] 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.) 



