128 BOTANY. 



Liquidambar , Nyssa, Sassafras, Celtis, Morus, Carya, Quernis, Cas- 

 tanea, yuniperus, Platanns^-' On the other hand, one of the most 

 abundant and characteristic forest trees of the mountains, the Yellow 

 Birch [Betida lutea Michx.), extends only as a chance straggler into 

 the lower country. This species, however, among the deciduous 

 trees, and the Balsam Fir and Black Spruce [Abies balsamea Marshall, 

 and A. nigra Poir.) among the evergreens, were the only larger trees 

 which the contrasted Flora does not also possess. Continuing the list 

 of important absences from the mountain Flora, the following genera 

 and species of smaller trees, shrubs, and woody plants may be 

 mentioned: EiioiiyimLS, Corims fiorida L., Viburnum prunifolium L. 

 Vaccifiiiun vacillans Sol., Leucothoe, Andromeda ligustrina Muhl., 

 Clethra, Azalea viscosa L., Lindera, Myrica, and Alnus serrulata Ait. 



Of the arborescent and woody vegetation of the mountains the fol- 

 lowing species I have never observed about Riverdale : Acer Penn- 

 sylvanicum L., and A. spicatuni Lam., Pyrus Americana DeC, Ame- 

 lanchier Canadensis oligocarpa Gra)', Ribcs Cynosbati L., R. rotundi- 

 foliu7nyi'\c\\yi.,R. lacustrc Vo\x., R. prosiratumXJW^x .,2^x1^ R.Jiirtellum 

 Michx., Loniccra ciliata Muhl., Sambucns pitbens Michx. (occurs on 

 Palisades in Lower Hudson Valley), Viburnum midum cassinoides 

 Gray, V. opulus L., V. lantanoides Michx., RJwdodendroii maximum 

 L., Ilex IcEvigata Gray, Corylus rostrata Ait., Taxus baccata Cana- 

 densis Gray, NemopantJies CanadeJtsis DeC. 



The foregoing comparison is, of course, merely a superficial one 

 dealing only with more prominent species, and many other names 

 might have been mentioned. 



More than three hundred and twenty-five species of trees and 

 plants, exclusive of Vascular Cryptogams, were observed during my 

 stay in the mountains, and of these the names of some seventy-five 

 do not appear on my records of the Riverdale Flora. Nearly fifty 

 of the number mentioned, however, are not indigenous to the region, 



* Representatives of the latter five were noticed sparingly in the main valley, but did not occur 

 in the mountains. 



