GRAMINEAB (GEASS FAMILY) 



169 



198. E. virgrinicus. 

 Two spikelets X 1, 

 Spikelet with glumes 



detached x 2. 

 Floret X 2. 



* Glumes as long as the lemmas or nearly so. 



*- Glumes and le.mmas 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., JSf. S. to ria., 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. HiRSUTioLtMis 

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

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

 and Neb. Var. suBjifrTicus Hook. Lemma and glumes 

 awnless or short awn-pointed, scabrous. — 0. to Minn., Kan., 

 and westw. 



++ ++ Glumes straight, not or but little indurated at base. 



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



2. E. anstrHlis 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. canadensis L. Green or glaucous ; culms 

 6-16 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. GLAiJcirdLius (Muhl.) 

 Gray is the very glaucous form but corresponds 

 more nearly with tlie 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- 



Spikelet with glumes detached, (errupted 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 'S 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. ARKANsXNt7.s (Scribn. & Ball) Hitchc. Glumes 

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



194. E. canadensis x %. 

 Two spikelets. 



195. E. striatus x %. 

 Two spikelets. 

 Spikelet with glumes detached. 



, and southw. 



