298 BOTANICAL GAZETTE [APRIL 
frequently to be seen toward the base of an encroaching dune, 
resembling the line of willows and dogwoods shown in fig, 5. 
Of course, Hypericum has nothing like the plasticity and endur- 
ance of Salix; nevertheless it may live for many years if the 
dune advances slowly. Its capacity for vertical elongation is 
much less than that of Salix or Cornus, so that a rapid advance 
would soon cover the plants and cause their death, Near the 
South Chicago beach is a pool with a dense vegetation of Sar 
pus pungens about its margin. This plant has served to collecta 
small amount of sand, and is forming a low secondary dune, 
Although a large portion of each shoot is covered by the sand, 
there is as yet no sign of etiolation on the aerial parts of the plant. 
Since the highest portion of a wandering dune is close to its 
advancing front, it is evident that a buried forest will gradually 
become uncovered, as the dune passes on beyond. No scene 
all the dune area is more desolate than such a place. It 's#@ 
veritable graveyard, where the corpses once buried are exposed 
again. Fig. 17 shows a pine graveyard which has hada history 
like this. In the background are several living pines, pre 
ably members of the same forest with the others. Their position 
at the summit of a hill permitted them to survive, while those 
at lower levels were buried by the sand. The uncovered pile 
trunks are directly in the path of the main wind meee 
hence are subjected to the severest action of the sand-P t 
The trunks are carved and battered away until the last remnan 
of the old vegetation passes away forever. de 
Graveyards similar to those at Dune Park occu oe 
extensive dune-complex at Glen Haven. - The commonest “7 
tree there appears to be the arbor vitae, though there ar “A 
sional dead trees of birch and ash. In addition to the "™ 
trees, there is an abundance of resurrected soil line 
tudes on the complex. These black streaks in the sa 
greatly in depth and persistence. Doubtless the mise on 
thus exposed is sometimes utilized by the scanty pe by the 
the complex, but more commonly it is rapidly scattere 
winds. 
