26o MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 



In shallow pools, up to an altitude of 2500 m. 



Montana: Sphynx, 1887, Tvjccdy, lyj. 



Yellowstone Park : Yellowstone Lake, 1885, Tzceedy, ^08. 



Elatine Americana Arn. Edinb. Journ. Nat. & Geogr. Sci. i : 430' 

 [Man. R. M. 40: Syn. Fl. i^ : 281; 111. Fl. 2: 437; Bot. CaL 

 i: 80]. 



In shallow pools. 

 Montana: Lower Sand Coulee, 1891, R. S. Willianis, 8j^. 



* Elatine rubella. 



Whole plant reddish, low and depressed ; stems scarceh' more than 

 5 mm. long; leaves broadly obovate-spatulate, flesh}', about 2 mm., 

 long; flowers 3-merous ; pod depressed globose, 3-celled 1.5 mm. 

 in diameter ; seeds similar to those of S. A?ftericaua. 



It may be a form of £. Americana^ but the plant is much smaller, 

 the leaves very fleshy, and the flowers 3-merous. In volcanic sand, 

 at the edge of a pool. 



Yellowstone Park: near Yellowstone Lake, 1885, Tzvccdyy 



'439- 



* Elatine Williamsii. 



Stem 3-5 cm. long, rather slender; leaves broadly spatulate, 

 distinctly petioled, 5-8 mm. long, including the petiole, thin, indis- 

 tinctly 3-nerved ; flowers 4-merous, on pedicels 1-2 mm. long ; 

 seeds curved into a hook, less than 0.5 mm. long, with numerous 

 transverse lines. 



Nearest related to JS. Califoniica, but more slender, with thinner 

 leaves and much smaller seeds. In £. Califoniica they are almost 

 I mm. lon(j. The habit is more like that of E. triandra. 



Montana: Lower Sand Coulee, 189 1, R. S. Williams, 8jj; 

 Missoula, 1898, Williaiiis & Griffith. 



VIOLACEAE. 



Viola cognata Greene, Pittonia, 3: 145; Viola ciicullata Coulter, 



Man. R. M. 29; not Ait.; V. palmata ciicuUata Gray, Syn.. 



Fl. i^ : 196, in part. 



A near relative of V. cuciiUata of the eastern United States, but 

 without doubt distinct, as shown by Prof. Greene. It grows in rich 

 soil, especially on river banks, up to an altitude of 2000 m. 



Montana: Gallatin Co., Mrs. Alderson; Bozeman, 1892, IV. T.. 

 Shaw; Helena, 1891, F. D. Kelsey. 



