236 UNITED STATES GEOLOGICAL SURVEY— TERTIARY FLORA. 



the Gj'pses of Aix, St. Zaccharie, etc., a large ii amber of Aralla species, 

 thirty-three of whicli are described in Pale'ontologie V^g^tale by Schiinper. 

 But in Europe the genus disappears entirely long before the close of the 

 Miocene. One Panax only is found at Oeningen, and the only Miocene Aralla 

 is A. Zadclachi, Heer, known by a small fragment from the Baltic flora. 

 None has been identified in the Pliocene. This may explain the absence of 

 the genus in the European flora of our epoch ; while the predominance 

 of the genus in the Pliocene of the gold-bearing gravel of California may 

 account for the comparatively numerous species of Aralia of the present 

 United States flora, which counts six species on the eastern slope and two 

 on the Pacific coast. 



The living Araliacece have been actively studied, and the number of their 

 species considerably increased since the publication of the fourth volume of 

 the Prodromus, where they were described in 1830. Counting those of both 

 Aralia and Sciadojjhi/llum, thirty-two species only were then known. I am 

 not in position to state what is the distribution of the species of this genus 

 as known from more recent discoveries. The relation, however, of the fossil 

 species of this continent to those of the present flora is satisfactorily estab- 

 lished, if not by intimately related characters, at least by succession of types 

 from the Cretaceous until now. 



Aralia! gracilis, Lesqz. 

 Plate XXXIX, Fig. 1. 

 Llquidamiar graciJe, Lesqx., Annual Report, 1871, p. 287. 



Leaves Icng-petioled, palmately five-lobed, abruptly narrowed to the petiole; secondary nerves 

 thin, camptodrome, mostly erased. 



Considering the close relation of this leaf to those described as Liqui- 

 dambar in the Cretaceous Flora (pi. ii, figs. 1-3, and pi. xxiv, fig. 2), I could 

 but refer it to the same generic division, a reference which, however, has 

 been contradicted, and ascribed to the Araliacecp* The leaf is somewhat 

 thick, but not coriaceous, divided to above the middle in five lanceolate 

 acute lobes, separated by obtuse sinuses, with the borders very entire, broadly 

 cuneate to the petiole, and the lateral nerves curving quite near the borders, 

 which they follow in successive distinct bows. This species has still the 

 Cretaceous facies and characters. But, as said above, the same type is still 

 preserved in species of the Pliocene of California. 



Habitat. — Bridger's Pass, Wyoming (Dr. F. V. Hayden). 



' The question is discussed in the Annual Report, 1874, p. 323. 



