GRAMINEAE (GRASS FAMILY) 



169 



* Glumes as long as the lemmas or nearly so. 

 i- Glumes and lemmas rigid, all or only the latter awned. 

 -* Glumes bowed out, the base yellow and indurated for 1-2 mm. 

 1. E. virginicus L. Green or glaucous ; culms stout, 6-10 

 dm. high; sheaths smooth or hairy; blades 1.5-3 dm. long, 

 4-8 mm. wide, scabrous ; spike 4-14 cm. long, 12 mm. thick, 

 rigidly upright, often included at the base in the upper sheath ; 

 spikelets 2-3-flowered ; the lemmas smooth, bearing a scabrous 

 awn 4-18 mm. long, exceeding the lanceolate strongly-nerved 

 awn-pointed glabrous glumes. River banks, moist wood- 

 lands, etc., N. S. to Fla., and westw. July-Sept. In the 

 Linnean specimen the spike is exserted and the awn is about 

 the length of the lemma. FIG. 193. Var. HiRsuxiGLtiMis 

 (Scribn.) Hitchc. Glumes and lemmas hirsute, glumes some- 

 what narrower ; spike usually more slender. Me. to Va. 

 and Neb. Var. suBMtmcus Hook. Lemma and glumes 

 awnless or short awn-pointed, scabrous. O. to Minn., Kan., 

 and westw. 



193. E. virginicus. 

 Two spikelets x 1. 

 Spikelet with glumes 



detached x 2. 

 Floret x 2. 



-* -M. Glumes straight, not or but little indurated at base. 

 = Culms stout ; spikes 1-2 cm. thick. 



2. E. australis Scribn. & Ball. Intermediate between E. virginicus and the 

 next, green; culms 0.7-1.5 m. high, rather slender; leaves 2-4 dm. long, 

 narrowed toward the base; spike exserted, erect, 8-14 cm. long, 1.5-2 cm. thick; 

 glumes and lemmas hirsute ; awns spreading, often 

 2 cm. long. Woods and prairies, Ct. to Mo., and 

 southw. Glumes slightly indurated at base. 



3. E. canadSnsis L. Green or glaucous ; culms 

 6-15 dm. high ; leaves often 1-2 cm. broad ; spike 

 1-2 dm. long, exserted, soon nodding, loose or inter- 

 rupted below; glumes and lemmas hirsute, with 

 long spreading awns. Sandy soil, N. S. to Man., 

 and southw. FIG. 194. Var. GLADCiF6Lius (Muhl. ) 

 Gray is the very glaucous form but corresponds 

 more nearly with the Linnean type. 



4. E. robustus Scribn. & J. G. Sm. Differs from 

 the preceding in having a more robust and densely 

 flowered spike ; spikelets closely imbricated, not in- 

 terrupted at base ; the long awns divaricately spread- 

 ing. Low prairies, 111., and westw. 



5. E. brachystachys Scribn. & Ball. Resembles small specimens of E. cana- 

 densis ; culms 3-9 dm. high ; leaves 1-2 dm. long, 6-10 mm. wide, often some- 

 what involute, scabrous ; spike rather dense, or loose below, somewhat nodding, 

 8-15 cm. long; glumes and florets scabrous only, not hirsute; awns divergent. 

 Moist open or shaded grounds, Md. to Mich., S. Dak., and Mex. 



= Culms slender. 

 a. Spikelets spreading. 



6. E. striatus Willd. More or less pubescent; 

 culms 5-10 dm. high ; leaves 15-20 cm. long, pubescent 

 on the upper surface ; spike 7-10 cm. long, about 

 2.5 cm. thick, dense, usually nodding; spikelets 

 l-2(rarely 3)-flowered ; glumes awl-shaped, hispid or 

 hirsute, 2 or 3 times the length of the hirsute floret 

 which is only 6 mm. long, excluding the capillary awn 

 (2-3 cm. in length.} Rocky woods and banks, Me. 

 to S. Dak., s. to N. J. and Ark. July, Aug. FIG. 195. 

 Var. ARKANS\NI:S (Scribn. & Ball) Hitchc. Glumes 



194. E. canadensis x %. 

 Two spikelets. 

 Spikelet with glumes detached. 



195. E. striatus x %. 

 Two spikelets. 

 Spikelet with glumes detached. 



and lemmas glabrous or minutely scabrous. Md., la., and southw. 



