IMEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 7 



On river banks and in swamp lands, to an altitude of 2000 m. ; 

 rare. 



Yellowstone Park : Swan Lake, 1885, Tzuccdy, 862. 



Equisetum laevigatum A. Br. ; Engelm. Amer. Journ. Sci. 46: 871 



[Man. R. M. 445 ; Our Native Ferns, 135 ; 111. Fl. i : 38 ; Bot. 



Cal. 2: 331]. 



Common in wet meadows to an altitude of 1500 m. It is regarded 

 as a good hay plant. 



Montana: East Gallatin Swamps, July 24, 1896, Flochnan, ig; 

 Bear Creek Canon, 1892, W. T. Shazv ; Cottonwood Creek, 1892, 

 W. T. Shazu; Box Elder Creek, 1886, R. S. Williams, joj ; Twin 

 Bridges, 1892, //. M. Fitch. 



Equisetum variegatum Schleich, Cat. PI. Helvet. 27 [Man. R. M. 



446; Our Native Ferns, 135 : 111. Fl. i : 39]. 



On river banks and other wet places up to an altitude of 2000 m. 



Montana: Flathead River, 1892, R. S. WiHiains, g22. 



Yellowstone Park : Mammoth Hot Springs, 1885, Tivccdy^ 

 80^; Lower Geyser Basin, Coulter. 



Equisetum scirpoides Michx. Fl. Bor. Am. 2: 281 [Man. R. M. 



446; Our Native Ferns, 135; 111. Fl. i: 39]. 



On sandy shores and bars: rare. 



Montana: Columbia Falls, 1892, R. S. Williams, g2i. 



SELAGINELLACEAE. 



*Selaginella densa. 



Densely tufted ; sterile branches very short, crowded and generally 

 incurved; leaves densely crowded and many-ranked, 3-5 mm. long, 

 linear or in age almost needle-shaped, thickened, slightly flattened 

 dorsally, grooved on the back, ciliate on the margin, and tipped with 

 a white 1-2 mm. long bristle, fertile branches erect, 1-2 cm. long; 

 bracts imbricated, 4-ranked, thick, making the branches look 4- 

 angled, triangular-ovate, 1.5-2 mm. long, broadly triangular in cross- 

 section, deeply grooved on the back, ciliate on the margin, and 

 tipped with a white .3-. 7 mm. long bristle. 



It has been known as S. rupcstris, but is evidently distinct from the 

 plant of the eastern United States. Although there are scarcely anj' 

 good technical characters by which to separate the two, the striking dif- 

 ference in habit I think is sufficient. In S. dciisa, the sterile branches 

 are always very short, incurved, densely covered with narrower 

 leaves. The difference between leaves and bracts is more striking. 



