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. 16{j. 



b b. 3Iarginal nerves glabrous. 



11. P. triviXlis L. (Rough-stalkkd Meauow 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 0-15 cm. long, 

 resembling that of P. pratensis ; spikelets 2-3-llowered, 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.) 



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



flowering early. 



b. Spikelets 2-4 7mr. long ; lemmas broad, obtuse. 



12. P. sylvestris Gray. Culms siibcompressed, 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 jlexuous filiform branches spreading or 

 reflexed ; spikelets 2-4-flowered, 2.5-4 mm. lung; first glume I-, 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, weak, 3-10 dm. high ; sheaths compressed, 

 much shorter than the internodes; ligule 1-2 mm. long; blades 2.-'',-ll cm. 

 long, 2 mm. wide or less (rarely wader) ; 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 jg-r p^ alsodes. 

 5-10 cm. long, the basal ones much longer ; panicle 8-15 cm. long ; gpikdot x 3. 

 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. 



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

 obtuse apex; panicle diffuse, few-flowered. 



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

 long, 2-3 mm. wide ; panicle 8-20 cm. long, about as bn^ad, the capillary 

 flexuous spreading branches with a few spikelets near the ends; spikelets 4-()- 

 flowered, about 6 mm. long ; lemmas pubescent bnow between the strong nerves, 

 not loebbed at base. {P.flexuosa Muhl.) — Woods, N. J. and Pa. to Mo., and 

 southw. 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 icehhed 

 at base, keel and marginal nt^rves sparingly pubescent, intermediate nerves 

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

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



