10 CRETACEOUS AND TERTIARY FLORA. 



Quercus, Fagm, and Ficus, to which leaves have been referred in the Cre- 

 taceous Flora, do not require any observations. In this case, as in all the 

 determinations of fossil plants, the characters of the species are not 

 always satisfactorily established, but the generic affinities have been recog- 

 nized or passed by authors without any marked criticism. The generic 

 relation is specially positive for the remains referable to Myrica; one frag- 

 mentary leaf and some seeds have been already described in the " Gret. FL." 

 while two fine new species are added in this memoir. It seems equally so 

 for Quercus or its peculiar division, Dryophyllum, of which we have two 

 new species, and for Ficus, to which three species are added. 



Specimens of leaves referable to Platanus have been found in mod- 

 erate proportion both in Nebraska and Kansas. The first was described 

 by Heer, in the "Phyllites Cretacees du Nebraska,'' as Platanus Newberry i. 

 from a very incomplete fragment. The accuracy of this determination 

 was, however, subsequently verified by the discovery of more complete 

 leaves, figured in "Gret. Fl.,*' pi. viii, figs. 2 and 3, and pi. ix, fig. 3. 

 which show the narrowed base descending along the petiole lower than 

 the point of union of lateral primary veins, and also the tendency to a 

 three-lobed division, characters which are not observable in the fragment 

 which Professor Heer had for his examination. To this fine species have 

 been added : Platanus primceva, described from leaves so remarkably simi- 

 lar to those of P. aceroides of the Miocene that I was at first disposed to 

 consider them as identical. I have lately received numerous large leaves 

 of this species with specimens bearing fruits, which, very small, show a 

 great difference from those of the living species; then, P. Heerii, rare, like 

 the former, and found, as yet, only along the bluffs of the Salina River; 

 P. obtusiloba, from a number of somewhat fragmentary specimens from 

 Beatrice, Nebraska, representing leaves of about the same size and of 

 the same characters; and P. diminutiva — all species described and figured 

 in "Gret. Fl." The last one, as remarked in its description, may be a 

 dwarfed form of P. primceva or P. Heerii. The leaf appears as gnawed 

 along the veins by insects or perhaps by a parasite fungus. Its specifica- 

 tion is not positive and is subject to criticisms. The base of the leaf is 

 rounded to the petiole, a character as yet unique for a species of this kind. 

 P. recurvata should, following the opinion of my honored friend Saporta, be 



