70 



Platanus aceroides (?), Gopp., var. latior, Lesqx., American Journal of Science 



and Arts, (2), xlvi, 1868, p. 97. ' 



A large subcoriaceous leaf, 11 centimeters broad, 9 to 10 centimeters 

 long, without the petiole, obscurely palmately trilobate, distantly dentate; 

 teeth large, sharp-pointed, turned outside; lateral veins at ecpial distance, 

 parallel. 



Though the lobes of this leaf are less marked than in the common 

 form of P. aceroides, Gopp., being merely slightly longer than the teeth and 

 of the same form, I am still unable to find any positive character by which 

 this species may be satisfactorily separated from that of Goppert. The bor- 

 der base is undulate, more broadly truncate, not descending as far down along 

 the petiole. But in comparing our figure with that of Heer, (Flor. Tert. Helv., 

 PI. lxxxviii, Fig. 11,) one sees for the base of the leaves and the distribu- 

 tion of the nervation a perfect similarity. This identity of characters is still 

 more marked between the Cretaceous leaf and P. guillelmce,(xo\)\)., (in Schoss. 

 FX, PL xi, Fig. 1,) and as P. guillelmee, has been for a long time considered 

 by Heer as a variety of P. aceroides — an opinion still sustained by D. Etting- 

 hausen — I do not see the possibility of considering as reason for separation 

 the shortness of lateral lobes, which is so generally remarked in P. guillelmee, 

 and even in recognized varieties of P. aceroides. I have, however, changed 

 the name, to follow Heer's opinion, and substituted one which indicates this 

 species as the original form of a type, which has passed through the Tertiary, and 

 which is scarcely modified in our living P. occidentalis. 



The fragment represented PI. xxvi, Fig. 2 is evidently of the same 

 species. It is, however, different in its basilar nervation, or rather in the 

 lowest branches of the lateral primary nerves, which are not mere marginal 

 veinlets, but well-developed divisions, regularly branching. The two figures, 

 3 and 4, of Heer's PI. lxxxvii, loc. cit., show the same differences ; the larg- 

 est leaf, Fig. 3, having the lowest secondary veins simple, while in Fig. 4 the 

 corresponding veins of the same order are thicker and divided. 



Habitat. — Lancaster County, Nebraska, Hayden. In four specimens; 

 the last remarked one is from Salina River, Kansas. 



Platanus heerii, Lesqx., PI. viii, Fig. 4 ; PI. ix, Figs. 1-2. 



Leaves round or broadly rhotnboidal in outline, palmately three-lobed ; lobes short, obtuse ; borders 

 entire or undulate, oblique or wedge-form toward the petiole, aud more or less abruptly decurring along 

 i t ; petiole short. 



