Potamogeton POTAMOGETONACEAE Zannichellia 



Var. mucronatus (Fieb.) Graebn. 



Rare: in Scott's Run, Ruthby (NO), Commons, 4 Sept. 1896 



(A). 



P. foliosus Raf. var. macellus Fernald. 



In water of Brandy wine and Red Clay Creeks (NC). Not 

 known to have been collected since 1886. 



P. diversifolius Raf. (P. hybridus, in part, of Gray's Man., ed. 7.) 



Frequent in ponds and ditches, chiefly of the Coastal Plain. 

 Frt. June, July. 



Var. multidenticulatus (Morong) A. &. G. 



Rare: shallow ponds, Rehoboth (S), Commons, 15 July 1897 

 (A); Ellendale (S), Long & Bartram, 6 July 1913 (A). 



P. Spirillus Tuckerm. 



Rare: Wilmington, Commons, July — (A); ponds, Rehoboth (S), 

 Commons, 15 Aug. 1895 (A). Frt. late June to Aug. 



P. capillaceus Poir. 



Infrequent; ponds and ditches of the Coastal Plain. Frt. July, 

 Aug. 



^P. pectinatus L. 



Infrequent; in salt or brackish water, shores of Atlantic Ocean 

 and Chesapeake Bay. Frt. July. 



P. Robbinsii Oakes. 



Known only from the Chesapeake and Delaware Canal, near 

 Delaware City (NC), where it seems to have been last collected in 

 1897, by Tatnall & Commons. 



Ruppia L. 



• R. maritima L. Ditch Grass. 



Salt or brackish shores and streams; common on the Coastal 

 Plain from southeastern New Castle County southward. Frt. 

 July to Oct. 



Zannichellia L. 



V Z. palustris L. Horned Pondweed. 



Fresh or brackish streams and ditches in the northern part of 

 our Coastal Plain area; infrequent. Frt. June to Oct. 



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