30 LEAFLETS. 



southeastern Wyoming, July, 1894, A. Nelson. The description 

 is drawn from two sheets in my herbarium, bearing the collec- 

 tor's numbers 479 and 551, a duplicate of n. 551 also in TJ. S. 

 Herb. A fourth sheet I have seen in Herb. C. F. Baker, obtained 

 by Mr. Nelson from ponds along the river at Dunn's Eanch, 

 Albany Co., "Wy., 16 July, 1900, and numbered 7598; this quite 

 like the others except that it is glabrous altogether. Another 

 specimen in Mr. Baker's herbarium, collected by himself at Fort 

 Collins, Colorado, in 1894, has a scabrous peduncle and leaves 

 marginally serrulate-scabrous without other pubescence, while 

 one in Mr. Osterhout's collection from the same region is glab- 

 rous except as to the peduncle. Another Colorado specimen I 

 have that was obtained by myself on Clear Creek, a tributary of 

 the Platte, in 1870. But I do not feel very confident that all 

 these are part and parcel of F. Plattensis ; nor do I feel sure 

 that the floating-leaved plant which I have appended as an 

 aquatic phase of it really is such. This is Mr. Nelson's n. 7465 

 from Dunn's Eanch, July, 1900. Field study alone can enable 

 one to decide. 



P. SUBCORIACEA. Aquatic. Stems short, with internodes of 

 of an inch long, apparently submersed in shallow water ; float- 

 ing leaves subcoriaceeus, oblong, obtuse at both ends, 2 to 3 J 

 inches long, on firm petioles of f inch : spike solitary, ovoid, 

 hardly an inch long, on a stout peduncle of an inch or more: 

 achenes small, round ovate, polished but with an obvious scarcely 

 definable unevenness. 



Riparian state. Foliage much larger, not as firm in texture, 

 oblong-lanceolate, acute, subcordate, about 4 inches long and 

 about 2 in breadth, on petioles of 3} inches, both faces glab- 

 rous, but those smallest and near the spike distinctly though 

 minutely scabrous-serrulate without trace of other pubescence: 

 spike oblong, not longer than in the aquatic state but on a much 

 longer and notably glandular-hispid peduncle. 



This very satisfactory species rests at present on a single good 

 sheet in U. S. Herb., from the North Fork of Laramie Eiver, 

 Wyoming, twelve miles from Laramie Peak, collected by Charles 

 Schuchert, 24 Aug., 1899. The firmness of the foliage in the 

 aquatic, and the serrulate margin of the uppermost riparian 



