266 



IDENTIFICATION OF FOSSIL PLANTS. 



[Ch. XV. 



elm, Unger had previously given the name of P. Pichardi, identify 

 in? it with a tree now living in the Caucasus and Crete ; but Heer 



Fig. 205. 



Planera Jiichardi, Unger. P. Ungeri, Heer. 



Upper Miocene. (Heer, pi. 80, Flora Tert. Helvetia.) 



a. A branch from 03ningen. b. Fruit magnified. c. Leaf, (Eningen. 



had pointed out that in the fossil the size of the fruit was larger. 

 When, however, in 1861, the Swiss Professor visited with me the rich 

 herbarium of Kew, Dr. Hooker showed us a living variety of P. 

 Eichardi in which the fruit was fully as big as that of (Eningen, so 

 that this last must retain Unger's name, and this example, if there 

 were no other, might suffice to warn us, in the present imperfect 

 state of our knowledge, not to indulge in too positive a belief that all 

 the Miocene species have become extinct. 



Out of the 72 homologous species 

 above mentioned, 67 are phsenoga- 

 mous and only 5 cryptogamous ; but 

 it may well be doubted whether 

 among the 49 Miocene Cryptogamia 

 described in Heer's Flora Tertiaria, 

 a much greater number, perhaps 

 more than half, might not with pro- 

 priety have received (provisionally at 

 least) the names of living plants. 

 Heer admits that the majority come 

 very near to existing species, and we 

 know well how wide is the geo- 

 graphical range of the ferns, and 

 still more of flowerless plants of 

 lower grades, such as mosses, lich- 

 ,, ;i ens, and fungi, many species of which 

 niimeroiTs specimens of the fungus are cosmopolitan, and therefore fitted, 



called Rhyttsma vnduratum, Heer. r ' m 



b. Magnified view of the fungus. by their adaptability to varying con- 



(Heer, pi. 112, ^/O^Upper Miocene, ^.^ for fl 1()ng duration in time . 



