374 BOTANICAL GAZETTE [May 
evergreen series, and is in all probability a climax type, at least 
in certain situations. 
A very distinct type of coniferous forest is especially well 
developed at the south end of the lake. Since it is not devel- 
oped in exposed situations, or even on old dunes, but in low 
depressions between dunes, it may be called a pine bottom. 
These societies are developed where the soil is almost hydro- 
phytic. A common location for these miniature pine forests is 
about the gently sloping margin of an undrained swamp. Figs. 
9, 13,74, and 20 show them in such a situation. The line of 
demarcation between the sedge swamp and the pines is usually 
quite sharp. The surface of the soil where the pines grow may 
be less than a meter above the water level. 
The character tree of the pine bottoms is always Pinus Bank- 
stana. This species is, perhaps, less common than the white 
pine at the higher levels, but the white pine is rarely, if ever, 
present on the bottoms. No growth of trees anywhere in the 
dune region is so pure as the pine growth here. The most com- 
mon shrubs in these locations are Hypericum Kalmianum, Salis 
glaucophylla, Arctostaphylos Uva-ursi, and Juniperus COMME. 
Linnea borealis, Arabis lyrata, Fragaria Virginiana, and species of 
Pyrola are frequent. The development of the pine bottom floras 
was seen at several points. One of the most interesting cases 
was in a region of oak dunes, where a railroad company had 
removed considerable sand and lowered the level several mene 
Although surrounded on all sides by oaks and at some distance 
from a pine flora, the new flora at the lower level is develops 
into that of a pine bottom. os 
c. The rejuvenated dunes.—The instability of dune ae ies 
is not confined to the dune-complex. The capture or ames 
ment of a dune is liable to be stopped at any point and retro 
gression toward the active dune conditions instituted. Even ® 
have its 
dune that has long been completely established may wee 
come 
Process may be called rejuvenation. Any dune may be 
rejuvenated if the physical conditions are favorable, 
SS Se 
