748 GEOLOGY OF THE YELLOWSTONE NATIONAL PARK. 



there was some tendency to refer it to Platanus nobilis Newby., which is 

 sometimes slightly toothed. The teeth of the species under discussion are 

 distinctly aralioid, and not at all like those of P. nobilis. 



Aralia semdata is distantly related to A. digitata Ward, 1 from the 

 Fort Union beds. This latter species is 3-lobed, or, more often, 5-lobed, 

 with the lobes enlarged upward, and serrate with shallow teeth only 

 near the apex. A. macrophylla Newby., 2 from the Green River group of 

 Wyoming, has the lobes serrate, but the teeth are large, coarse, and often 

 scattered, and, moreover, the leaf is twice the size of this and always 

 5-lobed. 



A number of species of Aralia have been described from California, 

 but none of them agree with A. semdata. 



Habitat: Yellowstone River, one-half mile below the mouth of Elk 

 Creek, top of bluff; collected by F. H. Knowlton, August, 1888. 



Aralia whitneyi Lx. 



PI. XCIX, tig. 3. 



Aralia whitneyi Lx. : Foss. PL Aurif. Gravels, Mem. Mus. Comp. Zool., Vol. VI., No. 

 2, 1878, p. 20, PI. V, tig. 1. Haydeii's Aim. Kept. 1878, Pt. II, p. 49. 



This fine species was described by Lesquereux from the Auriferous 

 gravels of Chalk Bluff, Nevada County, California, and was also recognized 

 by him in material collected by Mr. W. H. Holmes on Fossil Forest Ridge 3 

 in 1878. The specimens here referred to this species come from probably 

 the same locality as that which afforded Holmes material. They are, with 

 one exception, larger leaves than described in the type. None of the 

 specimens are perfect, and hence it is difficult to determine the exact size, 

 but they must have been 15 to 20 cm. long and probabl}" broader. 



The small specimen mentioned is referred with some hesitation to this 

 species. It is only about 9 cm. broad and 7 cm. long, but otherwise hardly 

 differs. 



Habitat: Fossil Forest Ridge, Yellowstone National Park, bed No. 4, 

 "Aralia bed," small leaf only; bed No. 7, "Platanus bed;" Specimen 

 Ridge, Fossil Forest, opposite Slough Creek, and near head of Crystal 

 Creek, "Platanus bed;" several large fine leaves. 



1 Types of the Laramie Fl., p. 62, PI. XXVIII, fig. 1. 



-Proc. U. S. Nat. Mus., 1882, p. 513; Plates (inert.), PI. LXVII, fig. 1; PI. LXVIII, fig. 1. 



3 Of. Haydeii's Ann. Rept., 1878, Pt. II, p. 79. 



