100 POACEAE 



Pubescence of leaves of copious soft short appressed 



hairs. 

 Pubescence of leaves of long stiff spreading hairs. 

 Culms long hirsute below the racemes. 

 Culms glabrous. 



Spikelets I— 1.5 mm. long. 

 Spikelets 2-2.5 mm. long. 

 No branches arising from the uppermost leaf-sheath. 

 Spikelets 3 mm. long or less. 



Spikelets oval J^ as thick as broad or more, the 

 outer scales firm. 

 Leaf-sheaths glabrous, or sometimes ciliate; 



blades glabrous or hirsute on upper surface. 6. P. lame. 

 Leaf-sheaths as well as the blades hirsute. 7. P. plenipilum. 



Spikelets circular or nearly so M~H as thick as 

 broad, the outer scales thin and usually 

 wrinkled. 8. P. circidare. 



Spikelets more than 4 mm. long. 



Leaf-blades short, the larger ones 15 cm. or less. 9. P. difforme. 

 Leaf-blades long, exceeding 20 cm. 10. P. floridamim. 



1. P. dissectum Walt. (P. membranaceum Walt.)- Moist or wet 



ground: N. J. to Fla. and Tex. 



N. J. Rare from Camden Co., southward along the Delaware, and 



at Cape May, unknown elsewhere. 

 Pa. In ballast near Philadelphia. 



A rare and scattered species, perhaps only adventive with us. 



2. P. psammophilum Nash. In dry sandy soil: Mass., southern 



N. Y. to Del. 



Rare in Conn.; near Kingsbridge and Arlington, N. Y. City, 

 and on L. I.; and Fisher's Island, and scattered over the coastal 

 plain of N. J. 



3. P. pubescens Muhl. In fields and dry woods: Conn., N. Y. and 



N.J. to Tex. 



Conn. Reported but stations unknown. 



N. Y. Rare in northern Westchester Co., increasing southward. 



N. J. Scattered and local from Passaic Co. southward, except 



Cape May. 

 Pa. Montgomery, Bucks, Delaware and Chester counties. 



A rare and local species. 



4. P. setaceum Michx. In fields: N. H. to Neb., Fla. and Tex. 



Scattered throughout the northern part of the range, increasing 

 and common southward. 



