21 
p. 550, PL xxxiii, figs. 5-11; U.S. Geol. Surv., Bull. 37, 1887, p. 19, 
PI. Iv., figs. 5-8; PL V, figs. 1-3; Penhallow, Kept. Tert. PL Brit. CoL, 
'1908, p. 77; Knowlton, Wash. Acad. Sci., Proc., vol. 11, 1909, pp. 
185-215. 
“Populus nervosa var. 0 elongata Ny.” [Lesquereux], U.S. Geol. and Geog. 
Surv., Terr., 111., Cret. and Tert. PL, 1878, PL xiii, figs. 2-4. 
^‘Populus nebrascensis Ny.” [Lesquereux], op. cit,, PL xiv, fig. 7. 
Populus amblyrhyncha Ward, U.S. Geol. Surv., Sixth Ann. Kept., 1884-85 
[1886], p. 550, PL xxxiv, figs. 5-9; PL xxxv, figs. 1-6; idem. Bull. 37, 
1887, p. 20, PL vi, figs. 1-8; PL vii, figs. 1-3; Knowlton, Wash. Acad. 
Sci., Proc., vol. 11, 1909, pp. 188, 189, 194, 195, 198, 201, 202; Jour. 
Geol., vol. 19, 1911, p. 361; in Calvert, U.S. Geol. Surv., Bull. 471, 
1912, p. 16. 
Populus cyclomorpha Knowlton and Cockerell. U.S. Geol. Surv., Bull, 
696, p. 487, 1919. 
Populus roiundifolia Newberry, U.S. Nat. Mus,, Proc., vol. 5, 1882 [1883], 
p. 506; U.S. Geol. Surv., Mon. 35, 1898, p. 51, PL xxix, figs. 1-4; Pen- 
hallow, Kept. Tert. PL Brit. CoL, 1908, p. 79; Knowlton, Wash. Acad. 
Sci., Proc., vol. 11, 1909, p. 189. [Homonym, Griffith, 1847.] 
Populus cuneata Newberry [Lesquereux], U.S. Geol. and Geog. Surv., 
Terr., 111., Cret, and Tert. PL, 1878, PL xiv, figs. 1-4. 
In Ward’s account of the Fort Union flora he recorded thirteen species 
of Populus, although Newberry had previously recorded eight species, 
only one of which Ward found represented in his extensive collections. 
In Knowlton’s list of the Fort Union flora (1919, page 771) twenty-five 
species of Populus are listed. It seems obvious a priori that there were 
not twenty-five species of this genus in the Fort Union; and when one 
examines critically the published illustrations or the named specimens in 
the United States National Museum collections, it becomes equally obvious 
that a considerable number of these so-called species are without any basis 
and were frequently not recognized by their founders. Moreover, one 
becomes impressed with the unlikeness of many of them to Populus, a 
subject remarked on by Ward as far back as 1887. 
Newberry described the present species in 1868 and its chief feature 
was its more or less cuneate base. It is hardly necessary to give a detailed 
description of my conception of the species, suffice to say that these leaves 
are variable in size, and to a less degree in form, orbicular in general outline, 
bluntly pointed or rounded at the tip, and cuneate to rounded truncate at 
the base with long petioles. The margin may be entire or variably toothed. 
There are three basal or sub-basal primaries and the lowermost lateral 
secondaries may be sub-primary in character. The main lateral primaries 
are ascending and variably subacrodrome in character. 
Two extremes of this species are figured from the Ravenscrag beds at 
Ravenscrag butte (near the centre of sec. 27, tp. 6, range 23, W. 3rd mer.) 
They agree in all features except marginal character and are intimately 
associated in the deposit. As can be readily seen they are unlike any 
existing species of Populus, particularly in their venation, whereas, on the 
