156 GRAMINEAE (GRASS FAMILY) 



nerved. (P. glumaris Trin.) Gravelly seashores, Lower St. Lawrence R., and 

 northw.; also Alaska. (E. Asia.) 



*- -i- Culms tufted. 

 M. Alpine or high northern plants ; culms 4 dm. high or less. 



5. P. alpina L. Culms erect from a stout crown or caudex, rather stout, 

 0.5-4 din. high; upper blades much shorter than their sheaths, 3-6 mm. icide ; 

 panicle pyramidal, 3-7 cm. long, the filiform branches spreading, mostly naked 

 at the base ; spikelets rather crowded, broadly ovate, 3-6-flowered, 5-6 inin. long ; 

 lemmas 4 mm. long, villous on the midrib and margins. Brooksides, open 

 mountain slopes, etc., N. S., Isle Royale, northern shore of L. Superior, and 

 nortliw. June-Aug. (Eurasia.) 



6. P. laxa Haenke. Moss-green, forming loose tufts; culms slender, 2-4 dm. 

 high; blades about 2 mm. wide; panicle 2.5-7 cm. long, simple, often one-sided 

 ami nodding, loosely flowered, the filiform branches erect or ascending, spike- 

 let-bearing at the ends ; spikelets 2-4-flowered, about 5 mm. long ; lemma 3-3.5 

 mm. long, pilose on the midrib and margins toward the base. Alpine regions, 

 N. E., n. N. Y., and high northw. (Eu.) 



++ -M- Not strictly alpine ; culms taller or if low not decumbent at base. 

 = Panicle narrow ; lemma not webbed at the base. 



7. P. glaiica Vahl. Glaucous; culms strict, rather rigid, 1.5-6 dm. high; 

 sheaths crowded at the base ; blades 3-5 cm. long, about 2 mm. wide; ligule not 

 over 1 mm. long ; panicle 3-7 cm. long, rather compact, the short scabrous 

 branches erect; spikelets often purplish, 2-5-flowered, 5-6 mm. long; glumes 

 acute or acuminate ; lemmas 3-3.5 mm. long, villous on the keel and marginal 

 nerves below; intermediate nerves obscure. (P. caesia Sm.) Rocky shores 

 and mts., e. Que. and n. N. E. to n. Minn., northw. and westw. (Eurasia.) 



= = Panicle open, branches naked toward the base ; lemma webbed at the base 



except in no. 16. 



a. Spikelets numerous, more or less crowded. 

 b. Marginal and midnerve silky-pubescent. 



8. P. nemoralis L. Grass-green, 3-7 dm. high, rarely higher ; culms slen- 



der, less rigid than in the preceding, leafy throughout ; leaves 

 lax, 3-8 cm. long, 2 mm. wide ; panicle 4-10 cm. long, open and 

 spreading ; spikelets 2-5-flowered, 3-5 mm. long ; glumes sharply 

 acuminate ; lemmas 2-3 mm. long, intermediate nerves obscure, 

 a few webby hairs at base. Meadows and open woods, Nfd. 

 to Pa., w. to Minn., northw. and westw. June-Sept. (Eurasia.) 

 P. nemoralis. ^ IG - ^^*- Alpine forms may be low and erect, 1-2 dm. hiirh, 

 Snikelet x 3 with small narrow panicle, while luxuriant forms of lower alti- 

 tude may be creeping at base. 



9. P. triflbra Gilib. (FOWL MEADOW GRASS.) Culms 3-15 dm. high; sheaths 

 rather loose ; ligule 3-5 mm. long ; blades 8-15 cm. long, 2-& mm. 



wide, soft; panicle often purplish, 1-3 dm. long, pyramidal or 



oblong, the filiform spreading branches in remote fascicles o/3-lO, 



naked at the base ; spikelets 2-^-flowered, about 4 mm. long, 



hardly crowded; lemmas 2.5-3 mm. long, intermediate nerves 



obscure, webby hairs copious. (P. ftava Am. auth., not L. ; P. 



serotina Ehrh.) Wet meadows, Pa. to la., and northw; also 155. p. tri flora. 



cultivated. July, Aug. (Eurasia, n. A fr.) FIG. 165. Spikelet x 3. 



10. P. pratensis L. (JUNE GRASS, SPEAR GRASS, KENTUCKY 



j BLUE GRASS.) Culms 3-12 dm. high, sending out numerous 



AP running rootstncks from the base; sheaths compressed, overlap- 



Irrb ping below, ligule 1.5 mm. long; blades 1-6 mm. wide, those 



Bf of the culm 5-15 cm. long, the basal ones much longer; panicle 



pyramidal, the slender branches in rather remote fascicles of 3-5, 



166. P. pratensis. ascending, naked at base; spikelets crowded, 3-5-flowererl. 4-5 



Spikelet x 3. mm. long; lemmas 3 mm. long, copiously webbed at base; 



