The Flora of the Cayuga Lake Basin 51 



19. P. foliosus Raf. (P. pauciflorus of Cayuga Fl.) 



Ditches, pools, and slow-flowing streams; frequent. Fr. July-Sept. 



Pool in Enfield Creek n. w. of Key Hill; Jennings Pond; near Negundo Woods, 

 "a larger leaved form" (D.) ; near mouth of Fall Creek (/J.!); Dwycr Pond; 

 Union Springs; Cayuga; Lowery Ponds. 



N. B. to R. C, southw. to Fla., N. Mex., and Calif.; less frequenl on the Atlantic 

 Coastal Plain. Probably also in W. J. and Mex. 



20. P. vaginatus Turcz. (See Rhodora 18:131, 1916, and 20:I ( >1, 1918. /'. monili- 

 formis St. John. /'. pectinatus, var., no. 1008 of Cayuga Fl.) 



Deep water ; rare. 



Cayuga Lake, near the Ithaca lighthouse (D. !). Nearly always sterile. 

 Lab. to Sask. and Alberta, southw. to Cape Breton, s. N. B., N. Y., Wis., and 

 N. Dak. Found also in Eurasia. 



21. P. filiformis Pers., var. borealis (Raf.) St. John. (See Rhodora 18:134. 



1916. P. marinus of Cayuga Fl.) 



Shallow lake waters, usually with sandy and marly bottoms, perhaps influenced 

 by brackish conditions ; scarce. Fr. June-July. 



Renwick, under the pier ; Myers Point ; Sheldrake ; s. of Big Gully Point ; near 

 Howland Point; "near Union Springs" (D. !) ; Canoga Marshes. 



Newf. to Alaska, southw. to n. Me., N. Y., Pa., and Colo. Found also in India, 

 Tibet, and China. "Chiefly in calcareous waters" (St. John). 



22. P. pectinatus L. 



Slow streams, pools, and borders of lakes, in more or less brackish or strongly 

 calcareous waters ; locally common. Fr. Aug.-Sept. 



Rare in the Cayuga Lake Basin except in the waters and marshes of the lake and 

 in the Montezuma Marshes, where it is common ; found also in Newton Ponds and 

 in Mud Pond, McLean Bogs. A large, coarse form occurs near the lighthouses at 

 Ithaca, with larger leaves and much elongated peduncles (25 cm. long) but with 

 the contracted sheaths of P. pectinatus. This was discussed by Dudley under his 

 var., no. 1007. 



E. Newf. to B. C, southw. to Fla., Tex., and Calif.; infrequent on the Atlantic 

 Coastal Plain. Found also in Eu. 



23. P. Robbinsii Oakes. 



Lakes and very slow streams ; infrequent. 



"Abundant in all our lakes, but not yet found in flower or fruit" (D.); Cayuga; 

 near Ithaca (D. in C. U. Herb.). The infrequency of recent collections would 

 scarcely indicate that it is abundant, as Dudley states. 



N. B. to n. Ont, southw. to Del., Pa., and n. Ind. ; also Wyo. and s. B. C, to Nev. 

 and Wash. ; rare or absent on the Atlantic Coastal Plain. 



2. Ruppia L. 

 1. R. maritima L., var. longipes Hags. (See Rhodora 16: 125. 1914.) 



Salt or brackish waters ; rare. Fr. July. 



Salt Pond w. of Howland Island, 1916 (K. M. W. & F. P. Metcalf). 



Newf. to Fla., Tex., and Calif., along the coast, and inland in cent. N. Y. Found 

 also in W. I. and Asia. 



3. Zannichellia (Michx.) L. 

 1. Z. palustris L., var. major (Boen.) Koch. (See Rhodora 23:110. 1921. Z. pal- 

 ustris and var. pedunculate, of Cayuga Fl.) 

 Pools and ditches ; most common in the vicinity of salt springs, and perhaps 

 always dependent on traces of salt ; frequent. Fr. July-Aug. 



