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identity is undoubtful ; a Hedera, whose affinity is marked by the outline of 

 its coriaceous leaves, and still more by the nervation ; three species of Mag- 

 nolia, represented by a large number of leaves and recognized already in the 

 Phijllites by Heer; and four species of Liriodendron, the tulip-tree, whose form 

 of leaves, like that of the Sassafras, sufficiently proves the generic reference. 



Considering these genera separately in regard to their relations and to 

 their present and past distribution, we find Aralia still represented in our 

 flora by six species, all of different characters of leaves ; for, indeed, the 

 relation of the fossil form is rather to an old section of the Aralia, with com- 

 pound palmate leaves, now referred to the Hedera, like H. xalapcnsis of the 

 mountains of Mexico. This type is still represented by large leaves in the 

 Pliocene flora of California. H. helix, the ivy to which our Cretaceous species 

 H. ovalis is closely allied, is indigenous of Europe, where its origin is con- 

 firmed by paleontology, the species having been recognized in the Pliocene of 

 Italy. It is, however, of so easy acclimation with us that it looks like an old 

 wanderer returned home after a long absence. In the temperate zone of the 

 United States, it invades walls and stone-dwellings as it covers the ruins of 

 the European castles of old. The genus Aralia is not represented as yet in 

 the fossil Tertiary flora of Europe. 



But evidently these two most admirable genera of trees, Magnolia and 

 Liriodendron, belong to North America by origin, succession, and presence. 

 Of the eight species of true Magnolia (Magnoliastruvi) now known to botan- 

 ists, seven belong to the western slope of the temperate zone of North America, 

 and the other, M. mexicana, is either a variety of M. glauca or M. gran.diflora, 

 or even is referable to a different genus. We have seen that already two 

 species of Magnolia have been recognized by Heer in the Dakota group. I 

 have added one species to the number. In our Tertiary, we have still seven 

 species ; five of them in the Mississipj:>i Eocene, one at Carbon, and one at 

 Black Butte. Of the Mississippi species, two have been found in the Raton 

 Mountains, New Mexico, marking thus the genus with the same climatic dis- 

 tribution as it has now, or with wandering representatives far from the limits 

 of its area of general distribution. Thus, one of the species, M. inglefeldi, 

 found at Black Butte, is described by Heer from the flora of Greenland, just 

 as we find now groups of M. glauca and M. umbrella isolated in deep gorges 

 inNevv York, Pennsylvania, etc., farout of the mean range of habitatof thegenus. 

 In the Pliocene of California, the genus has two species. In the Tertiary for- 



