302 Rydberg: Studies on the Rocky Mountain flora 



form of the young leaves, which he described as being hastate. 

 His idea of the term hastate must have been rather strange, for 

 he figured the different leaf forms, and the form of leaf illustrated 

 as representing the young shoots is elongate-ovate with slightly 

 cordate base. 



It is represented in the herbarium of the New York Botanical 

 Garden by the following specimens: 



Alberta: Bow River, May 26, 1899, McCalla 2236. 



Montana: Flathead Lake, July 23, 1900, /. W. Blankinship; 

 Columbia Falls, September 14, 1892, R. S. Williams (both deter- 

 mined as P. balsamifera candicans) ; various localities in Montana, 

 Butler 124, 125, 126, 127, 128, 137. To this may also belong the 

 following, which are in leaf only: Butler 112, 113, 114, 135, 147. 



Idaho: Salubria, July 10, 1899, M. E. Jones 6541 (labeled P. 

 trichocarpa). 



Populus Besseyana Dode, loc. cit. 38 



Another poplar collected by Butler seems to be impossible to 

 identify with any of the accepted species. Butler's material is 

 all in leaf only, but there is in our collection one specimen 

 collected by Miss Isabel Mulford, in Idaho, which evidently 

 belongs here, and this specimen is in fruit. It is evidently related 

 to P. deltoides Marsh., but the leaf shape is different and the pedi- 

 cels are very short, shorter than the capsule. The young stems 

 are perfectly terete, not at all angled; the bases of the leaves of 

 the mature branches are rounded or subcuneate at the base and 

 more or less serrate along the base; the basal glands are small and 

 the petioles flattened. In P. Sargentii Dode the leaves are 

 flabellate-cordate, with an open concave sinus at the base, which 

 is toothless. The leaves resemble much P. acuminata Rydberg 

 but are broader and less cuneate at the base, and in the latter 

 species the petioles are terete. I adopt Dode's name, not because 

 I can definitely identify it by his diagnosis but because his illus- 

 trations of the leaves resemble those of this species. 



To this belong the following specimens: 



Idaho : Fish Haven, August 8, 1898, Isabel Mulford 263. 



Montana: Delta of Flathead River, Big Forks, Montana, 

 August 14, 1901, Umbach IQ2; and from several localities, Butler 

 109, in, 115, 116, 117, 120, 136, 139, 140, 144, 145, 149, 153. 



