142 POACEAE 



Spikelets 4-6 mm. long; panicle branches 



ascending or spreading. 6. P. grandis. 



Scales 2.5-4 mm - l° n g> truncate and denticulate 



at the apex. 7. P. pallida. 



Spikelets linear, 12 mm. long or more. 



Flowering scales 3-5 mm. long, obtuse, equalling or ex- 

 ceeding the obtuse palet. 

 Flowering scales firm, hispidulous all over, truncate. 8. P. septentrionalis. 



Flowering scales thin, hispidulous on the nerves only. 9. P. borealis. 

 Flowering scales 6-8 mm. long, usually shorter than the 

 acuminate palet. 

 Flowering scales obtuse, about 6 mm. long, a little 



exceeded by the palet. 10. P. fluitans. 



Flowering scales acute, about 8 mm. long, much ex- 

 ceeded by the palet. II. P. acutiflora. 



i. P. laxa Scribn. In moist places: N. S. to Me., N. J. and Pa. 



N. Y. Rare on and near Hempstead Plains, and elsewhere in 



southwestern L. I., unknown elsewhere. 

 N. J. Rare in Gloucester and Middlesex counties on the coastal 



plain, and at Lake Marcia, Sussex Co.; not in the pine-barrens. 

 Pa. Schuylkill and Monroe counties. 



Tertiary, o: Cretaceous, rare: Older Formations scattered. 123- 

 189 days. Sea level-2,500 ft. 



2. P. canadensis (Michx.) Kuntze. In swamps and marshes: 



Newf. to Minn., south to N. J. and Kans. 



Throughout the range, rare and perhaps adventive in the pine- 

 barrens, common northward. 



3. P. obtusa (Muhl.) Kuntze. In swamps: N. S. and N. B. to 



N. Y. and central Pa., south to Md. and N. Car. 



Conn. Southeastern counties and along the coast. 



N. Y. L. I. and S. I. 



N. J. Bergen Co. southward. 



Pa. Pocono Mts., Monroe Co. 



4. P. Torreyana (Spreng.) Merr. In wet woods: Me. and Que. 



to Minn., south to N. Car. and Ky. 



Conn. Rare along the coast, increasing northward. 

 N. Y. Local in the Bronx, and on L. I., increasing northward. 

 N. J. Rare in Monmouth Co., thence increasing northward. 

 Pa. Bucks Co. increasing and common northward. 



Tertiary o: Cretaceous, rare: Older Formations, increasing north 

 ward. ii7-i8Qdays. Sea level-4020 ft. 



