.. 



GRAMINEAE (GRASS FAMILY) 157 



intermediate nerves strong, glabrous. Fields and meadows throughout the U. S. 

 and B. C., naturalized in the East, indigenous in the North and West. May- 

 July. (Eurasia.) FIG. 166. 



b b. Marginal nerves glabrous. 



11. P. TRIVIALIS L. (ROUGH-STALKED MEADOW GRASS.) Culms erect from 

 a somewhat decumbent base, 3-9 dm. high, scabrous below the panicle ; sheaths 

 and blades retrorsely scabrous, ligule 4-6 mm. long; panicle 6-15 cm. long, 

 resembling that of P. pratensis ; spikelets 2-3-flowered, about 3 mm. long; 

 lemma strongly nerved, silky-pubescent on the keel only. Moist meadows and 

 roadsides, e. Que. to S. C. and La., rarely inland. May-Aug. (Nat. from Eu.) 



Spikelets fewer, scattered on slender pedicels; plants soft and smooth, 

 flowering early. 



b. Spikelets 2-4 mm. long ; lemmas broad, obtuse. 



12. P. sylvSstris Gray. Culms subcompressed, 3-12 dm. high ; sheaths 

 shorter than the internodes ; ligule 1 mm. long or less ; blades 2-6 mm. wide, 

 those of the culm 3-15 cm. long, the basal ones much longer ; panicle 1-2 dm. 

 long, oblong-pyramidal, the short flexuous filiform branches spreading or 

 reflexed; spikelets 2-4-flowered, 2.5-4 mm. long; first glume 1-, the second 

 3-nerved ; lemmas about 2.5 mm. long, often pubescent below, midnerve pubes- 

 cent to the summit. Rich woods and thickets, N. Y. to Wis., Neb., and southw. 

 Apr.-July. 



13. P. debilis Torr. Culms terete, iveak, 3-10 dm. high ; sheaths compressed, 

 much shorter than the internodes; ligule 1-2 mm. long; blades 2.5-11 cm. 

 long, 2 mm. wide or less (rarely wider) ; panicle nodding, 4-12 cm. long, the few 

 long capillary branches ascending or spreading at the ends, few-flowered; spike- 

 lets 2-4-flowered, 3-4 mm. long; lemmas glabrous, except the webbed base. 

 Rocky woodlands, e. Que. to Ont., southw. to Pa. and la. May, June. 



b b. Spikelets 5-6 mm. long ; lemmas lanceolate, acute. 



14. P. alsbdes Gray. Culms 2-6 dm. high ; sheaths thin, the uppermost elon- 

 gated, often sheathing the base of the panicle; blades 1.2-3 dm. long, 2-5 mm. 

 wide; panicle 1-2 dm. long, the filiform branches in 3's or 4's, 



finally spreading, or the lowest whorl ascending ; spikelets 2-3- 

 flowered, about 5 mm. long ; lemmas faintly nerved, villous on 

 the keel below. Wooded hillsides and thickets, e. Que. to Minn., 

 and southw. May, June. FIG. 167. 



15. P. W61fii Scribn. Culms slender, 4-9 dm. high ; leaves 

 mostly clustered at the base, 2 mm. wide or less, those of the culms 

 5-10 cm. long, the basal ones much longer ; panicle 8-15 cm. long ; 

 the spikelets somewhat clustered toward the ends of the ascending 



capillary branches, 2-4-flowered, 5-6 mm. long ; lemmas strongly nerved, the 

 marginal nerves and midnerve villous. Minn, and 111. to Tenn., rare. 



b b b. Spikelets 6-8 mm. long ; lemmas oblong, conspicuously scarious at the 

 obtuse apex; panicle diffuse, feiv-flowered. 



16. P. autumnMis Muhl. Culms slender, 3-9 dm. high ; leaves 5-12 cm. 

 g, 2-3 mm. wide ; panicle 8-20 cm. long, about as broad, the capillary 

 uous spreading branches with a few spikelets near the ends ; spikelets 4-6- 



ered, about 6 mm. long ; lemmas pubescent below between the strong nerves, 

 ivebbed at base. (P.flexuosa Muhl.) Woods, N. J. and Pa. to Mo., and 

 .thw. Mar.-May. 



17. P. brachyphylla Schultes. Culms 3-5 dm. high from running rootstocks, 

 2-3-leaved ; the upper leaves 1-5 cm. long, the basal ones about equaling the culm, 

 abruptly cuspidate-tipped; panicle 7-12 cm. long, the branches mostly in pairs, 

 spreading, spikelet-bearing at the ends ; spikelets 3-4-flowered ; lemma webbed 

 at base, keel and marginal nerves sparingly pubescent, intermediate nerves 

 prominent, naked. (P. brevifolia Muhl.) Rocky or hilly woodlands, Pa., Va., 



sparingly westw. to Ky. and 111. Apr., May. 



. 



