178 Part III. Chapter ı. 
Spiraen ı | Taxus i | Ulmophyllum 4 | Weinmannia 3 
Staphylea I Thyrsopteris 39 | Ulmus 24 | Widdringtonia 
Sterculia - 15.| Tilia 2 | Vaceinophyllum I i 
Styrax I Tmesipteris ı | Vaceinium 4 | 
Symphorocarpo- Toxylon(=Maclura) ı | Vallisneria . 
phyllum 2 Trapa 5 , Viburnites 3 | 
Taeniopteris 2 Tsuga ı  Viburnum 45 | 
Taxites 4 Tumion (=Torreya)5  Vitiphyllum 3 | Zostera 
Taxodium 9 Typha 2 } Mil 9 | 
Endemisms and glacial Plants. The North American Tertiary flora 
composed of the species of the genera noticed above, as well, as of numerous 
herbaceous and arborescent species, that existed in the past, but have not 
been preserved, covered practically the entire land areas of the continent a8 
it existed throughout the Cretaceous and Tertiary periods. The accompanying 
chart (see Fig. 3) will indicate that distribution, as determined theoretically 
from the relative position of the land and water arcas, for it is clear, that the 
evolution of our present flora took place on dry land during and through the 
physiographic changes which were instrumental in the shaping of the con- 
tinental land masses. As previousliy mentioned, the flora of the Eocene and 
the Miocene periods was fairly uniform in character from the Atlantic an 
Pacific oceans and from the American Mediterranean north and northwestwaf 
into the arctic regions and this flora was especially in the southern part © 
the Tertiary American continent of subtropic character. However, there 
appears to have been an indication, as early, as upper Cretaceous, of a 
separation of the eastern and western types of American vegetation, but this 
was not accentuated until the glacial period, because during Tertiary times, 
the western and the eastern parts of the continent were again united by @ 
land connection. ; 
We notice also a differentiation and isolation of certain Tertiary plants in 
the region of the southern Appalachian Mountains bringing about a p 
relict endemism. This isolation probably began before the glacial 
and was due to physiographic, rather than climatic causes. Oscillations of 
explained, Table Rock is an undenuded remnant of a former peneplain, : 
it is likely that Audsonia montana was once more extended in its distributio 
but has been isolated by the erosion of the larger part of the plain on which ® 
it formerly grew‘). The distribution of such local plants as Dicentra eximit, 
Shortia galacifolia, Lilium Grayi, Buckleya distichophylla, Neviusta alabamensisı 
Flliottia racemosa may have also a somewhat similar explanation. er 
1) HARSHBERGER: An ecological Study of the Flora of mountainous North Carolina loc. eit, 
PP- 247—248. 2 
