REMARKS ON THE SPECIES OF MIOCENE PLANTS. 



The 240 species of American Miocene plants named in the table rep- 

 resent the essential, more prominently distributed genera of plants living 

 now on the North American continent. The list has few species of Ferns, 

 but they are all of types recognized in the present North American Flora, 

 among them the living Onoclea sensibilis. It has a large number of Conifers, 

 the more generally distributed being Taxodium disiichum, the bald Cypress 

 of the Southern States, and Sequoia Langsdorfii, the ancestor of Sequoia 

 sempervirens, the Redwood of California. It has few Monocotyledons, 

 mostly Graminem and Oyperaceoe, with a Sagittaria, a Smilax, an Iris, and 

 three species of Palms. The Dicotyledons are as yet represented in the 

 Miocene of North America by five species of Myrica, one of which is the 

 type of M. Californica, another, that of Comptonia asplenifolia ; then by 

 a number of species of Betula, Alnus, Carpinus, Corylus, Fagus, Castanea, 

 Quercus, Salix, and Populus; indicating for the Miocene age of North Amer- 

 ica a distribution of the plants of these genera corresponding to that which 

 we have at the present time. Of Liquidambar, there are two species, or 

 two varieties of one, with six species of TJlmus, two of them representing 

 U. Americana and U. fulva, now living; then a number of species of 

 Ficus, Laurus, Persea, Viburnum, Diospyros, Aralia, Corylus, Magnolia, Tilia, 

 Acer, Sapindus, Ilex, Rhamnus, Juglans, and Rhus. Indeed, of all the 

 plants enumerated in the table there is only one whose type is not repro- 

 duced in the present vegetation of the North American continent. It is a 

 species referable to the Cinchonacece, described as Oinchonidium, and as yet 

 of uncertain botanical affinity. 



The representatives of some of the genera of the present North Ameri- 

 can arborescent vegetation have indeed not yet been recognized in the 

 American Miocene Flora, — Planera, Celtis, Carpinus, Liriodendron, Ptelea, 

 Vitis, Evonimus, Msculus, Cephalanthus, Kabnia, Azalea, and a few others; 



c F 18 273 



