GERMINATION OF SEEDS 97 
bases into short or sometimes long stalks. In the castor- 
bean and the squash, the cotyledons not only escape from 
the testa, but become green and work like ordinary leaves 
(Fig. 90). 
In corn, as in all the cereals, the embryo lies close against 
one side of the seed so that it is completely exposed by the 
splitting of the thin skin that covers it. In this case the 
single cotyledon is never freely expanded, but remains as 
an absorbing organ in contact with the starch-containing 
endosperm, while the root grows in one direction, and the 
stem, with its succession of unsheathing leaves, grows in the 
other direction (Fig. 91). 
