112 THE FLORA OF THE DAKOTA GROUP. 



Foss. Arct. (loc. cit.) Fig. la, or less distant, more divided, and more strongly 

 impressed as in Fig. lb of the same plate. They are, however, iigured thin- 

 ner and more flexuous in Heer's species than in the leaves from Kansas, of 

 which the lower part is broken, but which are evidently narrcnved and 

 cuneiform to the base. They are also comparable to G()})pert's Rhumnus 

 siihs'mnafHS (Palaeontogr., vol. 2, 1852, PI. vi. Fig. Id), at least by the form 

 and nervation of the leaves; the borders, however, being entire, not sinuous, 

 and the secondai'ies more divided. 



Habitat: Kansas. Nos. P and Q of the museum of the Universit}- of 

 Kansas. 



DiOSPYROS ROTUNDIFOLIA Lesq. 



PI. XVII, Figs. 8-11. 

 Cret. Fl., p. 89, PI. xxx, Fig. 1. 



Leaves of various size, subcoriaceous, entire, round or liroadl}- oval, 

 obtuse, declining at the base to the petiole; nervation caniptodronie. 



The leaves of this species, recently found in great mnnbers, are 

 extremely variable in size, from 1.5"™ to 7"" long, and from l*"" to 7'"' broad 

 in the middle. Some of the leaves are as broad as they are long; l)ut tlie 

 greatest number are oval and much longer than broad. 



The primary nerves are rigid; the secondaries, six to seven pairs, 

 oldique, at a broad angle of divergence of 50° to 60°, arched in traversing 

 the 1)lade and simply areolate along the borders by anastomosing curves, 

 mostly simple or branching near the borders. Tliougli the surface of the 

 leaves is quite smooth and tlie nerves very distinct, the ultimate areolation 

 is not discernible; in these specimens the areas only are seen traversed by 

 thin, simple nervilles, slightly oblique to the secondaries. The details of 

 areolation have been observed and figured upon the fragment in Cret. Fl. 

 (loc. cit.) Fig. 1, whicli appears to be referable to the same sjjecies, though 

 the leaf is a little larger and quite round. 



Besides the affinities of these leaves as indicated in the ('ret. Fl., they 

 lan also be compared to species of Populus, especially to 1\ h/jirrhorea and 

 ". SUfyia Heer, described above; also to the living Cocrolnha punctata, of 

 vhich a leaf is represented by impi'ession in Ettingshausen's Bilin Flora, 

 pt. 1, PI. XXIV, Fig. 1; and Coccoloha floridana Meisner, the leaves of which, 

 like those of the Dakota Group, are very variable in form and size. 



Habitat: Kansas. Abundantly found in nodules of Ellsworth Couuty. 

 Nos. 402, 436, 570, 572, etc., of the museum of the University of Kansas. 

 Collected by E. P. West. 



