1910.] NATURAL SCIENCES OF PHILADELPHIA. 553 



Chester. — Serpentine Ridge; West Chester; Sconnelltown; Union- 

 ville. 



— Nottingham Barrens. 



f25. Panicum sph^erocarpon Ell. 



Abundant on dry open barrens. 



Delaware. — Fawkes Run; Preston Run; Bear Hill; Blue Hill; 

 Mineral Hill; Middletown Barrens; Williamson; Lenni; Wawa. 



Chester.- — Sugartown Barrens; Serpentine Ridge; Cedar Barrens; 

 West Chester; Brinton's Quarry. 



— Nottingham Barrens. 



$26. Panicum boscii Poir. 



Frequent in dry or rocky border-woodland. 

 Delaware— Williamson; "Del. Co." (Dr. Geo. Smith). 



$27. Panicum clandestinum L. 



Frequent in moist border-land and edges of thicket. 

 Delaware. — Middletown Barrens ; Williamson. 

 Chester. — Sugartown Barrens. 



28. Homalocenchrus viRGiNicus (Willd.) Britton. 

 Common in shade of woodland. 



Delaware. — Fawkes Run; Middletown Barrens; Williamson; Wawa. 

 Chester. — Cedar Barrens; Unionville. 



29. Homalocenchrus oryzoides (L.) Poll. 



Frequent in rich swamps. 



Delaware. — Williamson. 



Chester. — Serpentine Ridge; West Chester; Unionville. 



30. Aristida dichotoma Michx. 



Abundant on dry open barrens. 



Delaware. — Fawkes Run; Preston Run; Mineral Hill; Middletown 

 Barrens; Williamson; Lenni; Wawa. 



Chester. — Sugartown Barrens; Serpentine Ridge; West Chester; 

 Sconnelltown; Brinton's Quarry ; Unionville. 



f31. Aristida oligantha Michx. 



Scarce; on dry open barrens. 

 Delaware. — Fawkes Run. 

 Chester. — Cedar Barrens. 



