AND ITS GERMINATION. 3 
the heart consists of a root and a stem in miniature. 
When the seed is examined after it has put forth its 
stem from the ground, the rootlet will be found to be 
increased to some extent, and to have taken a direction 
downwards, while the stem part has risen upwards. At 
a later period the seed-lobes will shrivel in the shell or 
testa, having given up what they contained for the 
nourishment of the young plant, which at this stage 
of its existence is able to grow without them. 
3. The following then are the most remarkable parts 
to be remembered in the seed: the scar or hilum (f.1. h.), 
the shell or testa (¢.); the two seed-lobes or cotyledons 
(c.), and the heart or corculum, (f. 2. ¢.) which consists 
of the rootlet or radicle (r.), and the stem-like part or 
plumule (pl.). The hilum having served for the passage 
of nourishment to the young seed while growing on 
the plant, and for the transmission of water in part 
while vegetating or germinating. The testa or shell 
being a protecting cover to the kernel, but able also to 
admit water to the interior while vegetation is going on. 
The seed-lobes or cotyledons are reservoirs or con- 
tainers of nourishment for the heart, to which they 
impart it whenever this organ begins to grow, which 
occurs when the seed is plaved under circumstances 
favourable to this end The radicle and plumule toge- 
ther compose the germ of the young plant, waiting in 
the seed the time when circumstances favourable to its 
growth shall be presented to it; which are, first, 
moisture, next air and heat; without which the seed 
cannot make any progress in growth: the moisture 
serves to dissolve the nourishment laid up in store; the 
