78 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



18. Panicum bicknellii Nash. 



Rocky woods between Chevy Chase, Glen Echo, and Great Falls; near Paint 

 Creek, west of Beltsville; infrequent. Eastern U. S. 

 Associated with Kalmia lalifolia, Panicum ashei, and Antennaria. 



19. Panicum microcarpon Muhl. 



Swampy borders and swales or alluvial stream banks; common, especially eastward. 

 Eastern U. S. (P. barbulatum of Britton's Manual.) 



Forming great tangled masses with conspicuously bearded nodes and small divari- 

 cate blades on slender scorpioid branchlets. 



20. Panicum annulum Ashe. 



Rather rich rocky woods, between Chevy Chase, Cleveland Park, and Great Falls; 

 infrequent. Atlantic states, above the Coastal Plain, and in Mo. and Miss. 



21. Panicum mattamuskeetense Ashe. 



Magnolia bogs; Beltsville and east of Hyattsville; rare. Atlantic Coastal Plain, 

 Long Isl. to N. C. 



22. Panicum clutei Nash. 



Boggy swale, Kenilworth; rare. Atlantic Coastal Plain, Mass.' to N. C. 

 Intergrades with P. mattamuskeetense; possibly only a form of that. 



23. Panicum dichotomuni L. 



Dry and sterile woods; common. Eastern U. S. 



24. Panicum barbulatum Michx. 



Sterile and rocky woods; commoner than P. dichotomum. Eastern U. S. 



25. Panicum yadkinense Ashe. 



MoiBt thickets and brushy places along streamlets; frequent. Southern Atlantic 

 states, north to Pa. 



26. Panicum lucidum Ashe. 



Magnolia bogs and boggy spots in pine woods; Takoma Park and eastward; found 

 in 1898 at Fort Myer. Southern states, north to N. Y, 



Forming large clumps, the vinelike culms with spreading glossy blades prostrate 

 among sphagnum and underbrush. 



27. Panicum spretum Sehult. 



Wet sandy open ground; College Park; rare. Atlantic Coastal Plain, Me. to Tex. 



28. Panicum lindheimeri Nash. 



Wet sandy meadows or low open woods; common. Atlantic Coast to the Great 

 Plains. 



29. Panicum meridionale Ashe. 



Sandy or rocky woods and copses; frequent. It. I. to Ala. 



30. Panicum albemarlense Ashe. 



Low saudy wood borders and clearings; frequent southeastward below the fall line. 

 Eastern U. S. 



31. Panicum huachucae Ashe. 



Open grassy ground; infrequent, Mississippi Valley and northeastward. 

 31a. Panicum huachucae silvicola Hitchc. & Chase. 

 Open woods and clearings; common. Eastern U. S. 



32. Panicum tennesseense Ashe. 



Wood borders and roadsides, usually in rather moist ground; common, especially 

 in the vicinity of the Potomac above Washington. Atlantic Coast to the Rocky Mts. 



33. Panicum villosissimum Nash. 



Dry or sandy open woods and clearings; common. Eastern U. S. 



34. Panicum pseudopubescens Nash, 



Dry sandy open woods; found at Kenilworth in 1899. Southern Atlantic states to 

 Conn. (P. ovale of Gray's Manual.) 



