8 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN, 



The bristles of the former are twice as long as those of the latter, 

 while in S. rupcstris there is little difference if any in the length of 

 the bristles. The grooves of the bracts are also much deeper in S. 

 densa than in S. riipesfris. The dense short sterile branches of the 

 former, their crowded leaves, the long bristles, and the- often yellow- 

 ish-green color make the species look still more moss-like than its 

 eastern ally. 



S. dciisa grows on exposed hill-sides, among gravel or rocks 

 throughout the Rock}' Mountain Region, extending eastward to the 

 Black Hills of Western Nebraska. The following specimens have 

 been examined from Montana. 



Montana: Little Rock}- Mountains, 1889, Dr. J^. Jlavard; Sil- 

 ver Bow Co. , J//'5. JoDi/'c Moore i Deer Lodge, Dr. JVczuberrx ; Park 

 Co., 1887, T-wecdy, 172: Wolf Creek, 1888, R. S. Williams, 334: 

 Ross' Hole, 1880, Waisoii: Missoula, 1898, Williams i.i- Griffith. 



LYCOPODIACEAE. 



Lycopodium annotinum L. Sp. PI. 1103 [Man. R. M. 436 ; Our Na- 

 tive Ferns, 137 : 111. Fl. i : 42 ; Bot. Cal. 2 : 349]. 

 In woods to an altitude of 2000 m. 

 Montana: Lake Teny, 1892, R. S. Willia)}is, p^y. 

 Yellowstone Park: East Fork, 1885, Tzcrcdy, 418; Upper 



Falls, Adams. 



ISOETACEAE. 



Isoetes Bolanderi Engelm. Amer. Nat. 8 : 214 [Man. R, M. 435: 



Our Native Ferns, 144; Bot. Cal. 2: 350]. 



In shallow w^ater and wet shores, at an altitude of 15-2500 m. 



Montana: East Boulder, 1887, Tzcccdy, 172. 



Yellowstone Park: 1873, C. C. Parry, joy ; Mudflats, Yel- 

 lowstone River, C. C. Parry (var. Parryi) ; Lewis Lake, 1884, P. 

 Tweedy, j/; Yellowstone Lake, 1885, Tiveedy, 416 (?). 



GYMNOSPERMAE. 



PINACEAE. 



Pinus flexilis James in Long's Exped. 2: 34 [Sargent, Silva, 11. 



35 ; Man. R. M. 431 ; Bot. Cal. 2 : 124]. 



It is a rather rare tree, growing scattered on hillsides up to an alti- 

 tude of 3000 m. 



