POACEAE. 37 



the upper ones imperfect, the raehilla articulated between the flowers. Scales 

 several-many, the 2 lower empty, the flowering ones broader, rigid, rounded on 

 the back, obtuse to acuminate, awned or awnless, the nerves connivent at the 

 apex or confluent into the awn, the remaining scales, if any, empty; palet shorter 

 than the scale, 2-keeled, the keels usually ciliate. Stamens 3. Styles very short, 

 distinct. Stigmas plumose. — Wheat-grass. 



1. A. repens (L.) Beauv. Stems 3-12 dm. tall, from a long rootstock: leaf -blades 

 7-30 cm. long, 2-10 mm. wide: spike 5-20 cm. long: spikelets 3-7-flowered, 

 the empty scales strongly 5-7-nerved, usually acute or awn-pointed, sometimes 

 obtuse, the flowering scales glabrous, acute or short-awned. — Bather common 

 in cultivated grounds and waste places. Nat. of Eu. — Sum. — Couch-grass. 

 Quitch-grass. Quick-grass. 



48. ELYMUS L. Usually tall perennial grasses, with flat or convolute 

 often rigid leaf -blades and a terminal cylindric dense spike which is sometimes 

 interrupted and usually covered with long awns. Spikelets numerous, sessile, 

 crowded, usually in alternate pairs, sometimes in 3 's or more, at each node of 

 the continuous rachis, 2-several-flowered (rarely 1-flowered). Scales 4-several 

 (rarely 3). the 2 lower empty, rigid, awn-like, subulate, or linear, persistent, 

 awn-pointed or awned, those at each node forming an apperent involucre, the 

 flowering, usually in pairs, rarely in 3 's, sessile, the clusters alternate or opposite, 

 acute, usually awned, rarely awnless, the remaining scales if any smaller and 

 empty; palet shorter than the scale, 2-keeled. Stamens 3. Styles very short, 

 distinct. Stigmas plumose. — Lyme-grass. Wild-rye. 



Empty scales narrowly subulate: spike relatively slender. 1. E. striatus. 



Empty scales linear or linear-lanceolate : spike relatively 

 stout. 

 Flowering scales glabrous. 2. E. virginicus. 



Flowering scales pubescent. 



Empty scales linear, thick, the awn usually shorter 



than the body. 3. E. hirsutiglumis. 



Empty scales narrowly lanceolate, thin, the awn as 

 long as the body or longer. 

 Flowering scales hirsute. 4. E. canadensis. 



Flowering scales minutely hispidulous. 5. E. glabrifiorus. 



1. E. striatus Willd. Stems 3-9 dm. tall: leaf -sheaths glabrous or hirsute; 

 blades 1-2. .5 dm. long. 4-10 mm. wide : spike 6-12 cm. loner, often nodding, 

 slender : spikelets 1-3-flowered, the empty scales 2-2.-5 cm. long, including the 

 slender rough awn, 1-3-nerved, the nerves, and often the whole scale, hirsute, 

 the flowering scales about 6 mm. long, hispid, each bearing a slender awn 1.5- 

 3 cm. long. — S. Bather rare, on roadsides and in woods. — Schists. — Sum. 



2. E. virginicus L. Stems 6-9 dm. tall: leaf -sheaths sometimes pubescent, 

 the uppermost u.sually inflated and enclosing the base of the spike; blades 1-3.5 

 dm. long, 4-16 mm. wide: spike 5-18 cm. long, broad, stout, upright: spikelets 

 2-3-flowered, the empty scales very thick and rigid, lanceolate, 1.5-2.5 cm. long, 

 including the short awn, 5-7-nerved, the flowering scales 6-8 mm. long, each 

 bearing a rough awn 4-18 mm. long, or rarely awnless. — Bather common, in 

 moist thickets or on banks. — Sum. 



3. E. hirsutiglumis Seribn. & Sm. Stems 3-9 dm. tall: blades 2-3 dm. long, 

 8-18 mm. wide: spike 6-15 cm. long, stout: spikelets 2-5-flowered, the empty 

 scales linear, 10-12 mm. long, thick, 3-5-nerved, the nerves hirsute, each acumi- 

 nate into an awn as long as or shorter than the body of the scale, the flowering 

 scales lanceolate, 8—10 mm. long, each acuminate into a rough awn 12-16 mm. 

 long. — Lower Susquehanna valley. Bather rare, on the river shores and 

 islands. — Schists. — Sum. 



