AKT. 12 FOSSIL PLANTS FROM WYOMING BROWN 9 



liquidambars, with the exception of the unusually long lobes and the 

 restricted area of the basal region. From an esthetic point of view 

 the tree which bore these delicately graceful leaves was undoubtedly 

 a striking object in the Cretaceous landscape along the river courses 

 and moist low country of southwestern Wyoming. 



A review of liquidambar history discloses no earlier undoubted 

 liquidambar than this. Several Cretaceous leaves have been called 

 liquidambars, but because they have entire margins they are not now 

 regarded as such. Not until Eocene and Miocene times did the 

 liquidambars leave plentiful remains both of leaves and fruits. 



Holotype.—V.S.'^M. No. 39146. 



ROSACEAE 



PRUNUS ASPENSIS, new species 



Plate 2, Figure 4 



This is an oblong to lanceolate leaf with finely serrate margin, 

 rounded base, and short petiole. Nature of the apex unknown. 

 Approximate length 5 cm, width 2 cm. The venation is not clearly 

 shown, but is pinnate with secondaries emerging fromi the midrib 

 at 50° and becoming camptodrome near the margin. Finer venation 

 undeterminable. The affinities of this leaf seem to me to be with 

 the Rosaceae and I assign it to the genus Prunu^. There are no 

 Cretaceous species of Primus so far as I know with which this could 

 be identified. 



Holotype.—V.^.'^M. No. 39147. 



STAPHYLEACEAE 

 STAPHYLEA? FREMONTI Knowlton 



Plate 1, Figure 8 



Staphylea? fremonti Knowltox, U. S. Geol. Surv. Prof. Paper 108, p. 93, pi. 32, 

 figs. 4, 5; pi. 33, fig. 5, 1917. 



The specimen figured here and the only one of the sort in this 

 collection is at least a trifoliate leaf, but may be the terminal portion 

 of a leaf which had more leaflets. Points of difference between this 

 specimen and those figured by Knowlton are: Petiole of middle 

 leaflet longer than those of the laterals ; base of leaflets rounder ; sec- 

 ondary veins less numerous. All these differences may be within the 

 limits of variation in the species, and, therefore, I hesitate to desig- 

 nate a new species for this specimen from the Aspen formation. The 

 question mark following the generic name, it seems to me, is much to 

 the point. 



Plesiotype.—U.S.^M. No. 39148. 



