168 THE VEGETABLE WORLD. 
Tue SEED. 
The Seed is the essential part of the fruit. It represents out- 
wardly a system of protecting coverings, which are generally 
double. The various appearances presented by different seeds are 
owing to this covering. 
Seeds are sometimes smooth, like those of Tobacco (Fig. 250) or 
Pip RLcSuined Tig BH. Seed igh Feud ig 254—seedo Hi a Sal 
the Pear (Fig. 252), sometimes wrinkled and rough-skinned, as in 
the Fennel (Fig. 253) ; or papillous or warty, as in the Chickweed 
(Stellaria), Fig. 254; honey-combed with alveolar depressions, 28 
in the Field Poppy (Fig. 255); winged, asin the Pine (Fig. 256), oF 
Fig. ie < Seed of Fig, 256 zie Fig. 258.—Seed of Cotton Tree. 
hairy, as in the Cotton Plant (Figs. 257 and 258), with hairs rising 
from the apex, as in Asclepias, from the base in the Willow. 
The whole of the seed enveloped and protected by these integu- 
ments, is called the kernel, or nucleus. 
The essential character of the Kernel is, that it contains the 
