106 THE CAYUGA FLORA. 



997. P. crispus, L. (C. by Dr. Wright.) 



Sterile forms exceedingly abundant in deeper water of inlet and 

 lake; fertile in shallower channels and ditches. Rarely fertile 

 near Ithaca in June-July. Abundant in flower and fruit in spring- 

 brook entering west side of Black Lake, Aug. 15, 1885. (Fruits in 

 the Inlet at Watkins. ) (Dr. Wright says it has increased in I.. 

 Keuka, enormously within a few years, to the exclusion of othei 

 species once abundant.) 



99S. P. zosteraefolius, Sebum. {P. comprcssus, L., Man., p. 488.) 



(H. and C.) 

 Frequent in Cayuga L., Summit Marsh, Dryden L. , Locke Pond, 

 Mill-ponds at Red Mills and Malloryville. Our forms are robust, 

 resembling Schollcra in the water. 



999. P. obtusifolius, M. and K. 



Summit Marsh, in the shallow water not far from the northern- 

 most island, where it occurs but sparingly. Aug. 



My specimens are short and bushy on account of the habitat, but 

 they otherwise agree closely with specimens from Germany and 

 from Tenn. The latter, sent me by Professor Porter, seem to be 

 nearer the type than his own from "Dillerville Swamp." There 

 are two conspicuous glands at the base of each leaf in all specimens 

 I have seen. These are not noticed in any of the descriptions. Mr. 

 Morong has since written me that they are always present in this 

 rare species. 



1000. P. Hillii, Morong. (See Botan. Gazette, VI, p. 291.) 

 Cayuga L. on Myers Pt. In pools north and south of Ithaca. In 



the Inlet. Dryden L. and Red Mills pond ; not uncommon. July, 

 Aug. 



First collected in 1875 but referred to P. pauciflorus, Pursh. until 

 P. Hillii was published. It fruits earlier than P. pauciflorus. 

 " Stem about i° long, slender and widely branching. Leaves all 

 submerged, linear, acute \'-2y' 2 ' long, % f, -\% ,r wide, 3-nerved, 

 the lateral nerves delicate and nearer the margins than the midrib, 

 the midrib often compound below. Stipules free, whitish, obtuse, 

 striate, 3 // -5 // long. Peduncles short spreading or somewhat re- 

 curved, more or less clavate. Spikes capitate, 3-6 fruited. Fruit 

 obliquely obovate about lj^ // X l}4 // , tricarinate on the back, the 

 front slightly arched, obtuse at base. Style nearly facial, short, 

 recurved. Embryo with apex pointing transversely inward." 

 Hitherto reported only from Ohio and westward ; but in the Rob- 

 dins Herb, from Dr. Hoysradt, of Dutchess Co., {Mr. Morong.) 



1001. P. pauciflorus, Pursh. (H. and Wright in C.) 

 Fall Creek near the mouth. Ditches near Esty's Tannery. Near 



Negundo Woods, (a larger leaved form); not common. Aug. 



1002. P. pusillus, L., (the var. vulgaris of "Mau., p. 489.) (H. and C.) 

 Near mouth of Fall Cr. ; scarce and not in fruit. 



1003. P. pusillus, L. , var. major, Fries. 



Fall Cr. near the mouth, and Cayuga L. west of the breakwater. 

 Cayuga bridge. 



