58 POACEAE. 



panicle loose and open, suberect, 10-15 cm. long; spikelets 3-6-flowered; 

 lemma firm, keeled toward the apex, S-nerved, acute or sometimes mucronate, 

 smooth or nearly so, 6—7 mm. long. 

 Common in alpine meadows. 



Festuca occidentalis Hook. Densely tufted, the whole plant smooth and 

 bright green; stems 30-60 cm. high; leaf blades smooth, becoming longitudi- 

 nally grooved when dry; panicle narrow, loose, 8-20 cm. long, often drooping 

 at the summit; spikelets green, 3-5-flowered; lemmas scabrous near the apex 

 or smooth, 5-6 mm. long, bearing a slender awn of equal length. 



In open woods, common. 



Festuca ovina supina (Schur) Hack. Plant densely tufted, usually 

 smooth; stems 10-20 cm. high; leaves firm, involute, not shrinking when dry; 

 panicle strict, narrow, 2-4 cm. long; lemmas short-awned; ovar>' not hairy 

 at apex. 



In the mountains at high altitudes. 



Festuca elatior L. Meadow Fescue. Perennial; the stout stem 100-150 

 cm. tall, smooth and glabrous throughout; leaves flat, dark green, 7-15 cm. 

 long, 3-4 mm. wide; panicle narrow, erect, 10-25 cm. long, the branches soli- 

 tary or in twos; spikelets rather crowded, lanceolate-oblong, 12-18 mm. long, 

 5-10-flowered; lemma scarious-margined, acute, awnless. 



A native of Europe, escaped from cultivation. 



Festuca subulifiora Scribn. Stems 60-80 cm. high; leaves broad, flat or 

 loosely involute; panicle broad, the spreading rays mostly solitary; spikelets 

 large, loose; lemmas long awned, each narrowed at base into a stalk-like 

 structure, so that the rachilla is apparently jointed between the florets. 



In open woods, not common. 



Festuca subulata Trin. Loosely tufted, glabrous or nearly so; stems 40- 

 120 cm. high; leaf blades flat, thin, 3-10 mm. broad; panicle very loose and 

 somewhat drooping, 15-40 cm. long, rays in 3-5 sets; spikelets pale green, 

 3— 5-flowered, 7-12 mm. long; lemma membranaceous, narrowly lanceolate, 

 keeled its entire length, 5-7 mm. long, with an awn 5-20 mm. long. 



In moist woods, common. 



83. PANICULARIA. 



Tall aquatic perennial grasses with terminal panicles; spikelets 

 few-many-flowered, terete, or somewhat flattened; glumes un- 

 equal, obtuse or acute, 1-3-nerved; lemmas membranous, obtuse, 

 rounded on the back, 5-9-nerved, the nerves disappearing in the 

 hyaline apex; palea scarcely shorter than the lemma, rarely 

 longer; grain smooth, enclosed in the lemma and palea, free, 

 or when dry slightly adhering to the latter. 



Spikelets linear, 10-20 mm. long. 



Lemma scabrid only on the nerves; glumes 2-3 mm. long. P. borealis. 

 Lemma scabrid all over the back; glumes 1-2 mm. long. 



Spikelets 10-15 mm. long; lemma 3 mm. long, truncate. P. leptostachya. 

 Spikelets 18-20 mm. long; lemma 5-6 mm. long, acut- 



ish. P. occidentalis. 



Spikelets ovate or oblong, 2-8 mm. long 



Lemma with 5 prominent nerves. P. pauciflora. 



Lemma with 7 prominent nerves. 



Spikelets 3-4 mm. long. P. nervata. 



Spikelets 4-6 mm. long. P. americana. 



