216 FLORA OF THE GREEN RIVER GROUP. 



Of the 166 species of vegetable forms recognized in the specimens of 

 Florissant, 50 are related to and 40 identical with Miocene species of Europe, 

 while the affinity to the lower Tertiary, or Oligocene, of Germany is marked 

 by 8 related and 4 identical species, and to the flora of the Gypses of Aix 

 by 28 related and 16 identical species. 



At first sight it seems that the types of the flora of Florissant 

 are more distinctly Miocene, even upper Miocene, for two of its species rep- 

 resent plants living at the present time or which at least are so closely allied 

 to them that it is scarcely possible to deny identity. But searching for 

 more precise affinity, it will be remarked, first : that most of the species 

 related to or identical with Miocene plants are species of wide distribution, 

 which have been found in a large number of European localities from Italy 

 to the Baltic, and on the American continent from Wyoming Territory and 

 California to Oregon and Alaska ; then to Greenland, Spitzbergen, Sachalin, 

 &c. These plants have been described by a number of authors in different 

 works ; while the relationship to the flora of the Gypses of Aix refers to a 

 single locality in the south of France, the plants of which have been described 

 by one author only. Secondly, the more marked species, those represented 

 by the largest number of specimens and which may be considered as 

 peculiar to the group, are exclusively Oligocene — the mosses, the Rhizo- 

 carpeee in two species of Salvinia, the Ferns, the Conifers with very few excep- 

 tions, the Myricacece especially, as numerous and as distinct in their types 

 as they are in the flora of the Gypses of Aix, with which four of them are 

 intimately related and five identical, the beautiful Pojpulus Heerii, which, 

 described by Saporta from a single leaf, is represented at Florissant by 

 numerous fine specimens, the rare Populus oxyphylla, the abundant and 

 varied species of Lomatia and of Liospyros, the large splendid leaf of Aralia 

 dissecta very probably identical with Aralia multifida, Sap., species of Ilex, 

 Paliurus, and especially peculiar forms of Rhus, also described in the 

 "Etudes" of Saporta, give to the flora of Florissant a definite fades marking 

 its analogy with the Oligocene far more distinctly than it is with the Mio- 

 cene plants. This becomes evident in comparing the types of Florissant 

 with those of the Miocene, published in this volume. In the "Monde des 

 Plantes" Saporta enumerates as species, which he considers characteristic 

 of the flora of the Gypses of Aix, Aralia multifida, Cercis antiqua; seeds 



