1903] FLORA OF NORTH CAROLINA 313 
3. SUB-ALPINE DwarF TREE-SHRUB FORMATION (circa 6,000 *, 
1,830™). | 
Dendrium Association, Geum-Paronychia Association. 
4. SUB-ALPINE TREELESS ForRMATION (above 6,000*, 1,830™).3 
Rhododendron catawhtense Association. Dendrium Association. 
Alnus Assoctation, Lycopodtum-Geum Association. 
Carex-Poa Association. Knetfia-Hypericum Association, 
Polytrichum Association. 
ECOLOGIC SURVEY OF THE REGION. 
An ecologic survey of this region comprises a description of 
the flora of the north branch of the Swannanoa River and the 
slopes, ridges, and summits of Mount Mitchell and the mountains 
near it. The floras of the slopes and summit of Grandfather 
Mountain and of the summit and higher slopes of Roan Mountain 
are considered. 
MIXED DECIDUOUS FOREST FORMATION. 
The valley of the North Fork of the Swannanoa River is 
occupied by an arboreal vegetation, composed of Castanea den- 
tata, Liriodendron tulipifera, Fagus americana, Quercus alba, Q. 
rubra, Magnolia acuminata, Juglans cinerea, Quercus coccinea, 
Q. phellos, Acer saccharum, Betula lenta ( Castanea-Acer- Quercus 
Association). 
These- dominant trees are found somewhat back from the 
Streams, while near the streams, with their roots in the water, or 
where the lower parts of their trunks may be submerged during 
heavy rains, grow Platanus occidentalis, Tsuga canadensis, Betula 
lenta ( Tsuga Association) . 
In this forest, and belonging to the Castanea-Quercus-Acer 
Association, are these secondary species: Acer saccharum, Aescu- 
lus pavia, Juglans cinerea, Hamamelis virginiana, Hicoria glabra, 
Cornus florida, Tilia americana, Acer rubrum, Tilia heterophylla, 
Magnolia fraseri, Acer pennsylvanicum, and Robinia pseudacacia. 
As a third lower story of the forest, the following species 
occur: Kalmia latifolia, Cornus florida, Cornus alternifolia, Ilex 
monticola, Oxydendrum arboreum, Viburnum acerifolium. 
Mount Mitchell does not show formations 3 and 4, while Roan Mountain shows all 
32 
four well defined, Grandfather Mountain 3 and 4, but 4, if at all present, occupies a 
restricted area. 
