ART. 12 



FOSSIL PLANTS FROM WYOMING BROWN 



small staminate heads at intervals of 1 cm. The individual stamens 

 can not be distinguished readily. Associated with these flowers on 

 other blocks are portions of narrow striated leaves, which closely 

 resemble the leaves of modern sparganiums. 



The object with which this fossil may at once be compared is 

 that described by Lesquereux ^ from the Dakota sandstone of Kansas, 

 and called by him flowers of Platanus primaeva. Associated with 

 these flowers are undoubted Platanus leaves, so that the identifica- 

 tion of the flowers as Platanus flowers may be correct. On the 

 other hand, there are objects in the Dakota group described as 

 Podozamites which may be 

 Sparganium leaves instead. 

 I have found no Platanus 

 leaves in the Aspen collec- 

 tion, where the}" certainly 

 should have left fossil leaf 

 remains if Platarms had been 

 a tree along the Aspen river 

 courses. 



Boloty'pe.—V.^:^M.. No. 

 39140. 



SALICACEAE 



POPULUS? ASPENSIS, new species 



FiGXJBE 1 



The single specimen of 

 this species (fig. 1) is the 

 only one in this collection. 

 It is fragmentary but enough 

 is preserved to show the gen- 

 eral characters. The leaf 

 was orbicular, probably 6 cm 

 in diameter, with few large 



Figure 1. — Sketch of Populusf aspensif!. XI 



bhmt teeth on the margin and a cuneate base. From the top of 

 the petiole arises a palmate system of primary veins, which curve 

 upward toward the margin and send off secondaries toward the 

 teeth. The finer venation is obscure. The petiole is 2.5 cm long. 

 In general this leaf resembles those forms from the Fort Union 

 described as Populus, particularly P. cuneata Newberry, and illus- 

 trated by Ward.^ The teeth in the present specimen are coarser. 



' Lesquereux, Leo, The flora of the Dakota group. U. S. Geol. Surv. Mon. 17, p. 72, 

 pi. 8, figs. 8, 8b, 1892. 



*Ward, L. F., Types of the Laramie flora. U. S. Geol. Surv. Bull. 37, p. 19, pi. 4, 

 figs. .5-8 : pi. .5. flgs. 1-3. 1887. 



