222 Part III. Chapter 3. 
A consideration of the strand flora of New Jersey, which is well re- 
presented in the meadows of sedges, swamp rose mallow (Hibiscus moscheutos) 
and the forests of Pinus rigida, Funiperus virginiana &c. of the plate IV, reveals 
the fact that the time element is important in an explanation of the distribution 
of the sea-shore plants. If we contrast the character of the association of species 
on the northern and southern shore of New Jersey we find that the formations 
on Barnegat beach, for example, are usually open, while those on Wildwood 
beach are closed and have culminated in the forest type of vegetation. This 
argues for a greater age of the strand flora of Wildwood, as compared. with 
that for example at Sea Side Park in the north, and this conclusion is sub- 
stantiated by the fact that the bays behind the sandy sea islands are converted 
by the action of the tides and vegetation into salt marshes in the south, while 
in the north there are wide and open bays of brackish, or salt water”.. The 
development of this coast flora must have been subsequent to the post-Pens- 
auken uplift, but there is good reason to believe, that practically the same 
plants formed an association of species which fringed the continent wherever 
a’sandy or gradual shoreline was exposed to the action of the sea. These 
plants migrated along the shore with every elevation and depression, now 
fringing some recently formed sea-sound, now encroaching upon some recently 
emerged sandbank. We find an interesting confirmation in the presence of 
typic seashore plants on the coasts of the great lakes. Such plants as Am- 
mophila.arenaria (= A. arundinacea), Sabbatia angularis, Lathyrus maritimus, 
Gerardia purpurea, Euphorbia polygonifolia, Myrica carolinensis are found not 
only on the shore of the Great Lakes, but some of them at the Lake of the 
Woods. The most satisfactory explanation seems to be that in post-glacial 
times the valleys of.the St. Lawrence, Hudson, Lake Champlain and probably 
also lakes Ontario and Superior were then occupied by the sea, because of 
the northeast depression of the lands. During this period of submergence the 
typic seashore plants invaded the interior of the continent by way of the then 
existing seashore. Another interesting confirmation of the fact that the later 
periods of submergence and uplift had a powerful influence on the distribution , 
of sea coast species is found in the present distribution of the swamp rose 
mallow, /labiscus moscheutos, in the Atlantic coastal plain. This plant norm- 
ally occurs in brackish marshes from Massachusetts to Florida and Louisiana 
and on lake shores in saline situations locally in the interior to western Ontario. 
When it occurs in fresh water swamps, it is reasonably certain that these 
swamps represent converted salt marshes or bays which were present during 
a former time of submergence. New Jersey shows this best. During the 
Pensauken submergence, southern central New Jersey was a sea island separ- 
ated from northern New Jersey by Pensauken Sound. Hibiscus moscheutos \8 
its present distribution in New Jersey follows the former shore line of that 
1) HARSHBERGER, J. W.: An ecological Study of the New Jersey Strand Flora. Proceedings 
Academy of Natural Sciences of Philadelphia 1900: 623—671. Additional Observations On the 
Strand Flora of New Jersey, do. 1902: 642—669 i 
