70 



Plain, where the acid savannahs, bogs, shallow pools and dry 

 sands" supplied the environment in which they could still sur- 

 vive. In favorable habitats on the now uplifted peneplain, how- 

 ever, Kearney (3) thinks some Cretaceous species were able to 

 maintain themselves and so have survived as relict colonies, the 

 most ancient elements of the present Appalachian flora. In a 

 list of such species, common to both the Coastal Plain and the 

 mid-Appalachian region of West Virginia, there should be men- 

 tioned Kyllinga pumila, Orontium aquaticum, Xyris arenicola, 

 Xerophyllum asphodeloides, Amianthium muscaetoxicum, Me- 

 lanthium latifolium, Agave virginica, Phoradendron flavescens 

 Clitoria mariana, Stylosanthes biflora, Passiflora incarnata, 

 Rhexia virginica, Bartonia virginica, and Coreopsis major. The 

 great majority of the present species may be regarded as the 

 more or less modified descendants of this invading mesophytic 

 flora of late Mesozoic or early Cenozoic times. Many of the 

 genera, then widespread throughout the northern hemisphere, 

 have since been reduced by various exigencies to geographically 

 segregated remnants, persisting in widely separated places. 

 Among such ancient genera may be noted Arisaema, Symplocar- 

 pns, Chamaelirium, Aletris, Saururus, Menispermum, Zanthox- 

 ylum Podophyllum, Caulophyllum, Phytolacca, Madura, 

 Laportea, Magnolia, Penthorum, Ilamamelis, Liquidambar, 

 Hydrangea, Phryma and Triosteum. 



The Pleistocene glaciation did not reach West Virginia, the 

 terminal moraine being 25 miles or more from the northern 

 boundaries, yet it is probable that at that time at least the 

 northern part of the state must have presented the aspect of an 

 Arctic tundra, while many Canadian species were forced hun- 

 dreds of miles farther south. Upon the retreat of the ice sheet 

 and the consequent northward migration of biota, some of these 

 species were left behind on the cold mountain tops throughout 

 the Appalachians. Relict colonies of tundra, persisting in 

 mountain glades, were surrounded by the migrating forests and 

 are still in process of being replaced by succession (2). 



Probably reaching West Virginia since the last glaciation, 



there are a few species which have wandered eastward from the 



prairie province, such as Astragalus dis tortus, Silphium per- 



foliatum, Pentstemon canescens, and Asclepias verticillata. 



There should also be included in the flora a few species ap- 



