LANCE FLORA OF EASTERN WYOMING 149 



Family BIGNONIACE.-E 



Genus DOMBEYOPSIS Unger 



Dombeyopsis colgatensis Brown 



(Plate 14, Figs. 1, 4) 



Dombeyopsis colgatensis Brown, U. S. Geol. Surv. Prof. Paper 189, 252, pl. 60, figs. 1-4, 1939. Dorf, Bull. 

 Geol. Soc. Amer., vol. 51, 218, 222, 225, 1940. 



There are 5 well-pre.served specimens, 2 of which are figured, which agree in all essential 

 details of shape, venation, and marginal characters with the type specimens of this species from 

 the Colgate flora. The slightly larger size of the Lance Creek specimens is not considered of 

 taxonomic importance. 



Except for the attenuate and acuminate character of their bases and tips, the leaves of 

 Dombeyopsis colgatensis are comparable to those of D. ohtusa} In all the latter, however, the 

 bases are obtuse or only slightly attenuate and the leaf tips are invariably bluntly obtuse or 

 slightly emarginate. The venation of these two species is remarkably similar. No other close 

 resemblances to described species have been observed. 



As was pointed out by Brown, the reference of this leaf form to Dombeyopsis, impljdng rela- 

 tionship to the living Dombeya, is not wholly satisfactory. I have not been able to find any modern 

 leaves with comparable characters. 



Occurrence— Locality P3854. 



Collection-—\5. C. Mus. Pal., Plesiotypes Nos. 2542, 2543. 



Dombeyopsis obtusa Lesquereux 

 (Plate 14, Fig. 2) 



Dombeyopsis obiusa Lesquereux, U. S. Geol. and Geog. Surv. Terr., Ann. Rept. (1872), 375, 1873; Rept. U. S. 

 Geol. Surv. Terr., vol. 7, 255, pl. 47, figs. 4, 5, 1S78. Knowlton, U. S. Geol. Surv. Prof. Paper 130, 162, 

 pl. 13, fig. 4, pl. 20, fig. 11, pl. 27, figs. 1-4, 1922; U. S. Geol. Surv. Prof. Paper 155, 124, 1930. Dorf, 

 Carnegie Inst. Wash. Pub. No. 508, pt. I, 72, pl. 15, figs. 1, 2, 1938; Bull. Geol. Soc. Amer., vol. 51, 218, 

 222, 225, 1940. 



Phylliles populoides Knowlton, U. S. Geol. Surv. Prof. Paper 101, 280, pl. 50, figs. 1, 2, 1917. 



Populus? neomexicana Knowlton, U. S. Geol. Surv. Prof. Paper 101, 258, pl. 53, fig. 3, 1917. 



Phylliles trinervis Knowlton, U. S. Geol. Surv. Prof. Paper 130, 166, pl. 24, fig. 12, 1922. 



The collections contain 4 nearly complete specimens which are referable to this species. I 

 suspect that if a large suite of specimens of this species and of Dombeyopsis colgatensis were ever 

 obtained, there might appear to be gradational variations between these two species. The 

 consistent features of D. obtusa seem to be the obtuse character of both the bases and the tips of its 

 leaves. 



The occurrence of this species in the true Lance forraation further enhances its value as an 

 important index species of the Upper Cretaceous sediments of the Rocky Mountain region. It is 

 known elsewhere from the Laramie, Trinidad, Vermejo, lower Denver, Dawson, and Medicine 

 Bow formations, and has not been found in beds of known Paleocene or later age. 



The uncertain systematic status of this species has been discussed in my previous report, 

 cited above. 



Occurrence — Localities P3854, P3859. 



Collection—V. C. Mus. Pal., Plesiotype No. 2544. 



Dombeyopsis trivialis Lesquereux 



(Plate 13, Figs. 5, 6, 8) 



Dombeyopsii trivialis Lesquereux, U. S. Geol. and Geog. Surv. Terr., Ann. Rept. (1872), 380, 1873; Rept. U. S. 

 Geol. Surv. Terr., vol. 7, 255, pl. 47, fig. 3, 1878. Knowlton, U. S. Geol. Surv. Prof. Paper 130, 163, pl. 

 13, fig. 3, pl. 14, fig. 3, 1922. Dorf, Carnegie Inst. Wash. Pub. No. 508, pt. I, 72, pl. 15, fig. 4, pl. 16, 

 figs. 1, 2, 4, 1938; Bull. Geol. Soc. Amer., vol. 51, 218, 222, 225, 1940. 



i Lesquereux, L., Rept. U. S. Geol. Surv. Terr., vol. 7, 255, pl. 47, figs. 4, 5, 1878. Knowlton, U. S. Geol. Surv. Prof. 

 Paper 130, 162, pl. 13, fig. 4, pl. 20, fig. 11, pl. 27, figs. 1-i, 1922. Dorf, Carnegie Inst. Wash. Pub. No. 508, pt. I, 72, pl. 15, 

 figs. 1, 2, 1938. 



