156 GRAMINEAE (;gRASS FAMILY) 



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

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



1- ■•- Culms tufted. 

 ■*-*- 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 dm. high; upper blades much shorter than their sheaths, 3-6 mm. wide; 

 panicle pyiamidaU •^-'^ cm. long, the filiform branches spreading, mostly naked 

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

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

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

 northw. June-Aug. (Eurasia.) 



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

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

 and 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.) 



HH. 4H. Not strictly alpine; culms taller or if low not decumbent at base. 

 = Panicle narrow ; lemma not webbed at the base. 



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

 sheaths crowded at the base ; blades 3-5 cm. long, about 2 ram. 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; gkimes 

 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 bask 



except in no. 16. 



a. Spikelets numerous, more or less crowded. 



b. Marginal and midnerve silky -pubescent. 



8. P. nemoralis L. Grass-green, Z-1 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-floweied, 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.) 



164 P nemoralis ^^^- 164. — Alpine forms may be low and erect, 1-2 dm. high, 



S -^kelet X 8 '^^^^ ^"^^^^ narrow panicle, while luxuriant forms of lower alti- 



^' ^ ^ ' ■ tude may be creeping at base. 



9. P. triflbra Gilib. (Foavl Meadow Grass.) Culms^-V:) dm. high; sheaths 

 rather loose ; ligule 3-5 mm. long ; blades 8-15 cm. long, 2-4 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 2-4-flowered, about 4 mm. long, 

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

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

 serotina Ehrh.) — Wet meadows. Pa. to la., and northw; also i65. p. triflora. 

 cultivated. July, Aug. (Eurasia, n. Afr.) Fig. 165. Spikelet x 3. 



10. P. pratensis L. (June Grass, Spear Grass, Kentucky 



fBLUE Grass.) Culms 3-12 dm. high, sending out numerous 

 running rootstocks from the base; sheaths compressed, overlap- 

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

 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-flowered, 4-5 

 Spikelet X 8. mm. long; lemmas 3 mm. long, copiously webbed at base; 



