122 POACEAE 



N. J. Rare and local in Passaic and Hudson counties, increasing 



southward and common on the coastal plain. 

 Pa. Philadelphia, Delaware and Chester counties. 



Tertiary, common: Cretaceous, common: Older Formations, 

 scattered. 159-220 days. About sea level. 



27. Aristida L. 



Awns not articulated to the scale. 



Central awn coiled at the base. I . A . dichotoma. 



Central awn not coiled at the base. 



Spikelets exceeding 2 cm. long; first scale 5-7 nerved. 2. A. oligantha. 



Spikelets less than 1.5 cm. long; first scale 1-3 nerved. 

 Leaf-sheaths glabrous or sparsely pubescent. 



First scale generally shorter than or equalling 



the second. 3. A. gracilis. 



First scale exceeding the second. 4. A. purpurascens. 



Leaf-sheaths, at least the lower ones, densely woolly. 5. A. lanosa. 

 Awns articulated to the scale, united at the base into a spiral 



column. 6. A. tuberculosa. 



i. A. dichotoma Michx. Dry sandy soil: Me. to Neb., south to 

 Ga. and Tex. 



Throughout the range except the coastal region east of the pine- 

 barrens. 



2. A. oligantha Michx. In dry soil: N. J. to Neb. and Tex. 



N. J. Salem, Gloucester and Camden counties near the Delaware; 



reported from the streets of East Orange, by K. K. Mackenzie. 

 Pa. Philadelphia, Chester and Delaware counties. 



Tertiary, o: Cretaceous, rare: Older Formations, rare, most com- 

 mon on serpentine. 168-220 days. About sea level. 



3. A. gracilis Ell. In dry soil: N. H. to Mo., south to Fla. and 



Tex. 



Conn. Not uncommon along the coast, decreasing inland. 



N. Y. Rare on L. I., and S. I., unknown elsewhere. 



N. J. Throughout the state, rare northward. 



Pa. Northampton, Bucks, Montgomery, Philadelphia, Delaware 



and Chester counties. 



A plant whose distribution is not fully understood. 



4. A. purpurascens Poir. In dry soil: Mass. to Minn., south to 



Fla. and Tex. 

 Throughout the range, more common southward. 



