MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. IT3 



Yellowstone Park: Electric Peak, August i8, 1897, Rydberg- 

 & Bcsscy, jg2j. 



Salix petrophila Rvdberg, Bull. N. Y. Bot. Gard. i: 268; Salix 



arctica pctraca AndQi-s,. DC. Prod. 16": 287 [Man. R. M. 338; 



Bot. Cal. 2 : 90] : not S. feiraca Anders. 



This should, I think, be regarded as a distinct species, differing 

 from S. angioriim in the following respects : The leaves are narrower 

 and greener; branches more slender and not turning blackish in dry- 

 ing; catkins much smaller and narrower; and the capsule shorter, 

 rather ovoid and more densely villous. It is, however, much nearer 

 to the true S. aiigioniiin\\z\.n the plant of the Rockies which has been 

 regarded as that species. It grows up to an altitude of 2500 m. or 

 more. 



Yellowstone Park: Upper Falls, 187 1, Robert Adams; Stink- 

 ing Water, 1885, Tzcecdy, ^Sj. 



Montana: Mill Creek, 1887, Tzuecd\\ 2ji ; Boulder Creek, 2j2 ; 

 Old Hollowtop, near Pony, July 7, 1897, Rydberg & Bessey, jp2j; 

 Rocky Mountains, 1861, LyaJI : Upper Marias Pass, 1883, Caiiby, 

 28g, 2go and 2gi : ^McDonald's Peak, 2SS. 



* Salix tenera Anders.; DC. Prod. 16- : 288 [Rydberg, Bull. N. 



Y. Bot. Gard. i : 269]. 



This is nearly related to the preceding, differing in the narrow 

 oblanceolate leaves and the few-flowered catkins. The capsule is 

 also much shorter. It grows at an altitude of 3000 m. or more. 



Montana: Boulder Creek, 1887, Tn'ccdy, 2jj (?); Electric 

 Peak, August 18, 1897, Rydberg & Bessey, JQ22. (The last speci- 

 mens are exactly like the type.) 



Salix glaucops Anders. ; DC. Prod. 16- : 281 [Rydberg, Bull. N. Y. 



Bot. Gard. i : 270] ; Salix glauca villosa Anders. Sal. Bor. Am. 



22 [Man. R. M. 238; Bot. Cal. 2: 89] ; S. villosa Don; Hook. 



Fl. Bor. Am. 2: 144; notScheich, 



This represents S. glauca in the Rocky Mountains. It differs in 

 the shorter capsule, darker fuscous and acutish bracts and the 

 denser pubescence of the leaves. In age, the leaves, however, often 

 become glabrous (var. glabrescens Anders.) ; this is especially the 

 case at hicrh altitudes, and as it is then verv low it has been m.istaken 

 for S. angloruin {S. BrozLuiii l^nnd&i.), which is an arctic species. 

 At lower altitudes it becomes a taller shrub, often i m. high, and 



