160 POACEAE 



1. Elymus strtetus Willd. Stems 3-9 dm, tall : leaf -sheaths glabrous or hirsute ; 

 blades 1-2.5 dm. long, 4-10 mm. wide, pubescent above : spike 6-12 cm. long, often nod- 

 ding, slender : spikelets 1-3-flowered, the empty scales 2-2.5 cm. long, including the slen- 

 der rough awn, 1-3-nerved, the nerves, and often the whole scale, rough, hispid or hirsute, 

 the flowering scales about 6 mm. long, hispid or higpidulous, each bearing a slender awn 

 1.5-3 cm. long. 



In woods and on banks, Maine and Ontario to Tennessee, Nebraska and Kansas. Summer. 



2. Elymus Virginicus L. Stems 6-9 dm. tall : leaf-sheaths sometimes pubescent, 

 the uppermost usually inflated and enclosing the base of the spike : blades 1-3.5 dm. long, 

 4-16 mm. wide, rough : 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. 



In moist soil, especially along streams, Nova Scotia and New Brunswick to Manitoba, Florida and 

 Texas. Summer. 



3. Elymus hirsutiglumis Scribn. & Sm. Stems 3-9 dm. tall, erect : leaf-sheaths 

 longer than the internodes, the uppermost often inflated and enclosing the base of the spike ; 

 blades 2-3 dm. long, 8-18 mm. wide, very rough on both surfaces : spike 6-15 cm. long, 

 stout, the rachis pubescent : spikelets crowded in pairs, 2-5-flowered, the empty scales 

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



On river banks, Maine to North Carolina, Illinois and Nebraska. Summer. 



4. Elymus Caiiadensis L. Stems 6-15 dm. tall : leaf-blades 1-3 dm. long or more, 

 4-20 mm. wide, rough, sometimes glaucous : spike 1-3 dm. long, nodding, its peduncle 

 usually much exserted : spikelets 3-5-flowered, the empty scales awl-shaped, rigid, 3-5- 

 nerved, 16-32 mm. long, including the slender rough long awn, the flowering scales 8-14 

 mm. long, nearly glabrous to hirsute and each bearing a slender rough awn 2-5 cm. long. 



On river banks, Nova Scotia and New Brunswick to Alberta, Georgia, Texas and New Mexico. 

 Summer. 



5. Elymus robustus Scribn. & Sm. Stems 9-12 dm. tall, erect, stout: leaf -blades 

 firm, rough on both surfaces, 1-4 dm. long, 8-20 mm. wide : spike usually partially in- 

 cluded at the base, stout, strict, 1-2.5 dm. long, compact : spikelets numerous, crowded, in 

 2's-4's, 3-4-flowered, the empty scales 10-12 mm. long, each bearing an awn about twice as 

 long, the flowering scales lanceolate, 10-12 mm. long, from sparsely to densely appressed- 

 pubescent, each bearing an awn 3-4.5 cm. long. 



On river banks, Illinois to Arkansas, Montana and Kansas. Summer. 



120. HYSTRIX Moench. 



Usually tall grasses, with simple stems, flat leaf-blades and terminal spikes. Spikelets 

 numerous, at length spreading, 2-several-flowered, usually in pairs, rarely in 3's, sessile, 

 the clusters alternate on opposite sides of the continuous rachis, the rachilla articulated 

 below the flowering scales. Scales 2-several, the 2 lower empty, subulate, wanting in all 

 but the lowest spikelets, the flowering scales lanceolate, rigid, convolute, rounded on the 

 back, the nerves confluent into the long awn ; palet somewhat shorter than the scale, 2- 

 keeled. Stamens 3. Styles very short, distinct. Stigmas plumose. Grain oblong, ad- 

 herent to the palet when dry. 



1. Hystrix Hystrix (L. ) Millsp. Stems 6-12 dm. tall : leaf-blades 1-2.5 dm. long, 

 6-12 mm. wide, rough above : spike 7-18 cm. long : spikelets at length widely spreading, 

 8-12 mm. long, exclusive of the awn, readily deciduous, the empty scales present only some- 

 times in the lowest spikelets, the flowering scales 8-12 mm. long, each acuminate into an 

 awn about 2.5 cm. long. [Aspretta Hystrix (L. ) Willd.] 



In rocky woods, New Brunswick to Ontario and Minnesota, Georgia, Illinois and Nebraska. Sum- 

 mer. BOTTLE-BRUSH. 



121. ARUNDINARIA Michx. 



Tall shrubs, or rarely trees, with simple or branched stems, flat short-petioled leaf- 

 blades which are articulated to the sheath, and racemose or paniculate inflorescence. 

 Spikelets large, compressed, 2-many-flowered. Scales 3-many, the 2 lower empty, unequal, 

 the first smaller or sometimes wanting, the flowering scales longer, membranous, many- 

 nerved, at the apex obtuse, acuminate or with a short awn or mucronate ; palet scarcely 



