177 
where you go, from the peaks of the Catskill Mountains to the 
shores of the oceans, you will find poison ivy. Every year it 
becomes more widely distributed. This is due to its effective 
method of propagation, to its hardiness, and to its attractiveness. 
The seeds of poison ivy will develop under almost all conditions. 
Like many other seeds, they are not harmed by the cold of winter, 
so that when weather conditions are favorable, the mature plant 
develops. Poison ivy will adapt itself to many varying con- 
ditions, and its habits of growth under varying conditions are as 
variable as the conditions. It is without doubt one of our most 
attractive plants. Because of its beauty it is frequently allowed 
to grow beside old fences and unsightly hedges, which are com- 
soe covered by its luxuriant growth. 
ivy, depending on the conditions, grows as a trailing 
vine (Pate CX anaes a climbing vine (Plate CXXXVIID; or 
as b (Plate XIX). The trailing form is met w: 
most ce on borders of ese in meadows, a in 
open places between trees. Under these conditions the main 
stem trails along the ground, rooting at the joints and oe 
numerous aerial branches. When the trailing form comes in 
contact with a fence or shrub, it becomes climbing. ‘But instead 
of developing roots which function as absorbing organs it 
eds thousands of small roots which function as hold-fast 
ans. By means of these roocs it is able to climb the perpen- 
dicular face of a cliff or a tree trunk. From this vertical vine-like 
stem, numerous lateral br heen develop, some of which become 
attached to the tree, while others remain free. In some instances 
the branches of a tree and if the growth of the poison ivy is 
sufficiently vigorous it may completely overshadow the branches 
of the tree. 
The shrub form of poison ivy is usually found growing in open 
exposed places. When undisturbed, it grows to the size of a 
small tree with good sized branches. The trunk is often free 
from branches for several feet from the ground. The sprin 
foliage which develops annually on all forms is of an attractive 
reddish-purple color. This color is gradually replaced by the 
chlorophyll green of the mature leaf. 
