196 
quartz sand, which can be bought from local dealers, produces just 
as good results. The root-systems of these sand-barren plants are 
generally of two sorts: either thread-like roots which branch far 
and wide, as in the species of Hudsonia (H. ericoides, Fig. 8d, and 
HT. tomentosa), the broom crowberry (Corema Conradii), and the 
hearberry (Arctostaphylos Uva-ursi, Fig. 7b); or long tap roots, 
such as characterize the pine-barren sandwort (Arenaria caro- 
liuana), or the flowering spurge (Euphorbia corollata), or the 
ipecac spurge (Euphorbia Ipecacuanhae, Fig. 
8e), a species of 
won 
rous variability in color and shape of leaves. 
barren will al 
— 
In this sand 
so be found a species of blue-eyed grass (Sisyrinchiuim 
arenicola, hig. 8b), which is abundant on Long Island, three species 
of milkweed (Alsclepias tuberosa, A. amplevicaulis, and A. pur- 
purascens), and the wild pink (Silene pennsylvanica, Vig. 7c), 
which grows in sandy barrens on Long Island, though it is more 
frequent on gravelly banks. In this sand area the three-toothed 
cinquefoil (Potentilla tridentata, Vig. 8a) thrives 
a pl 
Co 
> southward it is 
ant of sterile mountain tops rather than of the coast, but it will 
grow in any kind of dry soil. 
Directly opposite the pond and sand barren is the beg. 
The 
term “bog,” 
in northeastern United States, re- 
place occupied by ericaceous shrubs and sedges, and 
is essentially ae When such an area is wholly invaded by 
trees, chiefly spruce and cedar, it becomes a swamp. In a bog the 
water is ordinarily acid; though “marl bogs’ in limestone regions 
are frequently alkaline and may lack the ericaceous plants. 
‘New Jersey bog” was one of the first developments in the 
ar 
as usually appliec 
fers to a wet 
This 
Garden, 
and was constructed in 1911 as an irregular basin of concrete about 
fifty feet long and eighteen inches deep, with six-inch walls and 
floor. This structure was filled with peat and sand brought up in 
barrels from the pine-barrens, and was one of the most successful 
elements of the original plantation. \WWhen the area was replanned, 
in 1931, on an ecological rather than a systematic basis, all mate- 
rial in the bog was removed, the surfaces were covered with 
asphalt, and the entire basin was filled to the brim with baled peat- 
moss. In the beginning aluminum sulphate was placed in the bog 
as an acidifier; but this treatment was soon discontinued, and the 
plants have grown just as well. The peat bog has been the easiest 
