82 POACEAE 



obtusa, nearly 4 mm. long, pubenilent, somewhat villous towards the base. P. 

 inntrva Scribn. & Merr. P. tenuifolia Buckk'v. in part. Plains and hills: Sask. 

 — Wyo.— Colo.— Utah— n Calif.— B.('. Subinont.—Mont. J(^J1. 



63. P. juncifolia Scribn. Stem glabrous 1.5-3 dm. high; blades of the 

 sterile shooLs about 5 cm. long, involute; those of the stem 2-5 cm. long, 1-2 

 mm. wide; jianicle narrow; spikclets 3-5-flowered, 5-6 mm. long; em])ty ghimes 

 ovate, usually obtuse, subeciual, 3-4 mm. long; lemma minutely scabrous on 

 the back, 3-4 mm. long, obtuse. Plains and meadows: Wyo. — Colo. — Utah. 

 Plain — Submont. Jl-Au. 



64. P. brachyglossa Piper. Stem glabrous, smooth, 6-10 dm. high; ligules 

 short, truncate; leaf-blades 5-20 cm. long, filiform, involute; panicle narrow, 1-2 

 dm. long; spikelets 7-10 mm. long, ;^-6-flowered ; empty glumes smooth, scarious- 

 margined, 4-5 mm. long, slightly imequal; lemma obtuse, smooth or nearly so. 

 Plains and meadows: B.C. — -n Calif. — Mont. Son. — Submont. Je-Jl. 



65. P. confusa Rydb. Stem 6-9 dm. high; basal leaf-blades 1-2 dm. long, 

 2-3 nmi. wide, fiat or involute, puberulent; stem-leaves several; blades about 1 

 dm. long; panicle narrow, 1-1.5 dm. long, dense; spikelets 7-8 mm. long, usually 

 4-fiowered; empty glumes lanceolate, shining, minutely strigulose above; lemma 

 narrow, about 3.5 mm. long, yellowish green, witli brownish scarious margins. 

 Meadows and benchlands: Alta. — Neb. — Colo. Plain — Mont. 



66. P. truncata Rydb. Stem about 9 dm. high, stiff; leaf-blades 1-2 dm. 

 long, 2-3.5 mm. wide, scabrous on the back; panicle about 1.5 dm. long, narrow; 

 spikelets 3-5-fiowered, 7-9 mm. long; empty glvunes 5-6 mm. long, tinged with 

 purple, scabrous on the nerves; lemma narrow, about 5 mm. long, straw-colored 

 or tinged with piu-ple, strigulose throughout. Hills and gulches: Colo. — Alta. 

 Submont. Jl-Au. 



67. P. ampla Merr. Stem 6-15 dm. high; leaf -blades flat, somewhat 

 glaucous, 15-25 cm. long, about 4 mm. wide; panicle 2-3 cm. thick and 1.5-3 dm. 

 long; spikelets 7-10 mm. long, 3-6-flowei'ed ; empty glumes lanceolate, acute, 

 scabrous on the keel and nerves; lemma 4.5-5 mm. long, lanceolate, scabrous 

 throughout, hispidulous on the keel. P. laevicidmis Williams. Hills and val- 

 leys: B.C.— Ore.— Mont. — Ida. Submont. Je-Jl. 



65. SCOLOCHLOA Link. 



Tall, aquatic perennials. Inflorescence paniculate. Spikclets 2-4-fiowered ; 

 flowers perfect. Empty glumes 2, thin-membranous, 3-5-nerved. licmma 

 rigid, with a ring of hairs at the base, rounded on the back, 5-7-nerved. Palet 

 usually equalling the lemma, 2-nerved. Styles very short; stigmas plumose. 

 Grain hairy at the apex. ^ 



1. S. festucacea (Willd.) Link. Stem 1-2 m. high, smooth; leaf-blades 

 1.5-4 dm. long, 4-8 mm. wide, flat, scabrous on the margins; panicle ojien, 2-3 

 dm. long; spikelets 6-8 mm. long; empty glumes acute, unequal, 3-5-nerved, 

 6-8 mm. long; lemma narrow, 5-6 mm. long. In water: Iowa — Neb. — Sask. — • 

 Ore.— B.C. Plain. JUAu. 



66. PANICULARIA Fabr. M.\nna-grass. 



Usually perennials with rootstocks (all ours), rarely annuals. Inflorescence 

 paniculate. Spikelets usually numerous, ovate to hnear, few-many-flowered, 

 the glabrous rachilla articulate between the flowers. Empty glumes 2, obtuse 

 or acute, unequal. Lemma obtuse or truncate, often denticulate, convex on 

 the back, but not keeled, prominently nerved, hyaline at the apex. Palet 2-keeled. 

 Styles short, distinct; stigmas plumose. [Glyccria R. Br.] 



Spikelets ovate or oblong, 6 mm. long or less. 



Lemma 7-nerve(i, obscurely denticulate at the apex. 



Spikelets 2-4 mm. long; lemma broadly oval, 1.5-2 mm. long. 



Leaf-blades flat and lax; lemma slightly scarious-margined ; branches of the | 

 inflorescence long; empty glumes obtuse. 

 Plant slender; branches of the inflorescence strongly ascending, nodding. 



1. P. nervala. 



