156 GRAMINEAE (GUASS FAMILY) 



nerved. (P. glumaris'Yr'm.) — Gravelly seashores, Lower St. Lawrence R., and 

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



-*- +- Culms tufted. 



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



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

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

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

 at the base ; spikelets rather crowded., broadly ovate., 3-6-11owered, 5-6 mm. long ; 

 lemmas 4 mm. long, villous on the midrib and margins. — Brookside.s, oi)eii 

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

 northw. June-Aug. (Eurasia.) 



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

 high; bladps 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-tiovvered, about 5 mm. long ; lemma 3-^15 

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

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



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

 = Panicle narrovj ; 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 tovmrd 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, S-7 dm. high, rarely higher ; culms slen- 

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

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

 spreading ; spikelets 2-5-fiowered, 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. Jnne-Sept. (Eurasia.) 



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

 Soikelet x ^ ' "^i^h small narrow panicle, while luxuriant forms of lower alti- 

 tude may be creeping at base. 



9. P. triflbra Gilib. (Fowl Meadow Grass.) CidmsZ-lbdm.high ; ^hediihs, 

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

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

 of/long, 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.) — NVet meadows. Pa. to la., and northw; also jg5 p triflora. 

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



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

 Blue 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 brandies in rather remote fascicles of 3-5, 



166. P. pratensis. asdending, naked at base ; spikelets crov^ded, 3-5-flowered, 4-5 

 Spikeletx.3. mm. long; lemmas 3 mm. long, copiously webbed at base,* 



