DESCRIPTIONS OF SPECIES. 109 



represented at the bottom of the figure, and that the central lobe was at 

 least 6 inches and the lateral lobes 3 or 4 inches larger than represented, it 

 will be seen that the leaf could not have been much less than a foot and a 

 half in length and breadth. These dimensions are rivaled by no living 

 species of Platanus, but I have fragments of the leaves of P. Baynoldsii 

 which could have been little less in size. 



The leaf figured on PI. XXXVII, fig. 1, is an immature form of this 

 species. This is established by its occurrence with the larger and more 

 deeply lobed leaves, with which it is connected by intermediate forms. 



Formation and locality: Tertiary (Eocene !). Near Fort Clark, Dakota. 



Platanus Raynoldsii Newb. 



PI. XXXV. 



Ann. N. Y. Lye. Nat. Hist., Vol. IX (April, 186S), p. 69; Ills. Cret. and Tert. PI. 

 (1S78), PI. XVIII. 



"Leaves of large size, sub-orbicular or rudely triangular in outline, 

 more or less rounded below, three-pointed above, often decurrent on to 

 the petiole, margins at base entire, on the sides and above, coarsely and 

 obtusely double-serrate, the lobes of the upper margin short and broad, less 

 produced than in most other species; nervation strong but open, haying 

 the general character of P. occidental-is and of the fossil species P. aceroides." 



Collected by Dr. F. V. Hayden. 



The younger leaves are rounded in outline and decurrent on the petiole. 

 Those more fully developed (which are sometimes 15 inches in length and 

 breadth), more triangular in form, not always decurrent, and having lobes 

 more produced, offer considerable resemblance to those of P. aceroides, an 

 extinct species from the Miocene of Europe, the nervation being similar in 

 kind and not greatly different in degree. The leaf is, however, always less 

 angular than in P. aceroides and P. Haydenii, and the character of the mar- 

 ginal serration is essentially different from that of any known species. In 

 P. aceroides the margins are set with long, acute, curved, simple teeth, as 

 in the living P. occidental-is ; in P. Haydenii the margins are for the most 

 part only sinuate; and in P. nobilis the middle lobes only are toothed, and 

 those but slightly; while in the species before us, with the exception of 

 the basal margin, the whole outline is marked by a broad, strong, double 

 dentation. 



