78 

 Populus latior cordifolia, Heer. 

 Bib : Fl. Tert. Helv. II„ 12, pi. LV, f. 4 : U. S. Geol. Surv. Terr., 1871, 289. 



There appears to be only one record for this form of Populus latior, from the Laramie 

 group of Medicine bow, "Wyoming. Its appearance in the collections of 1906, from the 

 Tulameen river, constitutes our first knowledge of it within Canadian limits. 



Populus mutabilis oblonga, Heer. 



Bib: Fl. Tert. Helv., II, 21, pi. LX, I 15, 16. 



The collections of 1906, from both the Tranquille river and Quilchena, contained frag- 

 mentary specimens of leaves which are to be referred to Populus mutabilis oblonga, Heer. 

 This European form has not been recorded from any other localities in either Canada or the 

 United States. 



Populus nebrascencis, Newb. 

 Bib : Lat. Ex. Fl., XXXV, 47, pi. XXVII, fig. 4, 5 : Geol. Surv. Can., VII, 1894, 36, 37 C. 



One specimen of this well characterized species was found in the 1906 collection from 

 Quilchena. It had already been observed in 1894, in collections from the Omineca river. 

 Newberry records it from the Fort Union group of the Yellowstone river, Montana, as well 

 as from the Denver group of Golden, Colorado. 



Populus nervosa, Newb. 

 Bib : Trans. R.S.C., V, 1887, iv, 35 : Lat. Ex. Flor., XXXV, 1868, 61. 



Newberry originally described this species from the Fort Union group of Montana. 

 Dawson later recorded it from the Lignite Tertiary of the North Saskatchewan at Rocky 

 Mountain house. 



Populus. obtrita, Dn. 



Bib : Trans. E.S.C., VIH, 1890, iv, 82, f. 12 ; VIII, 1902, iv, 16. 



So far as present records show Populus obtrita is an exclusively Canadian species. It 

 was first described by Sir William Dawson on the basis of specimens obtained from the 

 Similkameen river. It is so well characterized as to be distinguished without difficulty. 

 Since its first recognition it has been obtained from the Red Deer river and from Quilchena, 

 and in the collections of Mr. Lambe in 1906. It was also found in material from Quilchena 

 and the Similkameen river. 



Populus polymorpha, Newb. 

 Bib : Lat. Ex. Fl., XXXV, 50, pi. XLIX, f. 4, 7, 9 : Proc U. S. Nat. Mus., V, 1882, 506. 



Populus polymorpha is a somewhat rare species first obtained by Newberry from the 

 Miocene of Bridge creek, Oregon. In 1904 it was obtained by Ells and Johnston from Quil- 

 chena, and in 1906 it appeared in Lambe's collections from Coal gully, liritish Columbia. 

 As indicated by the name, the species presents wide variations of form, and it is altogether 

 probable that it really embraces more than one species. 



