14 THE VEGETABLE WORLD. 
ating their spurs into the bark of trees or on the surface of a wall 
they support the plant, but without nourishing it.* 
There is one family of plants, the Cuscutacee, which are, above 
all others, parasitic. 
They will grow on 
almost any plant they 
can lay hold of, pro- 
ducing in the autumn 
abundance of sweet- 
WINS 
they have attached 
themselves find their 
sap resistlessly drawn 
from them. The 
Dodder (Cuscuta Eu- 
ropea), Fig. 15, is an 
example where the 
suckers form true 
nourishing roots. 
e fundamental 
property of roots ina 
physiological point of 
view, is their constant endeavour to bury themselves in the earth. 
They seem to shun the light of day, and this tendency is to be 
remarked from the very first moment of the root showing itself 
in the germinating seed. It is a tendency so decided and appears _ 
so inherent in the life of all vegetables, that if we try to go 
contrary to it—if, for example, we reverse a germinating seed, 
placing it with the root upwards—the root and the stem will twist 
round of themselves ; the stem will stretch upwards, and the root 
eo bury itself in the ground. 
e can convince ourselves, by a very simple experiment, of the 
natural inclination which stems have ree kis light of day , and 
wall, and the pens accliedis ress goghes soto ll cay debi 
iG 
a? 
Fig. 15.—Suckers of the Dodder plant. 
f PLAN 
J 
up its life? Surely in those instances a 
Hea ces each adventiti t is draining the stem or 
wall to which it is attached of its sap, and transferring it to ite own veins.—Eo. 
