SPERMATOPHYTES: GYMNOSPERMS 
353 
transforms the integument into a hard bony covering, 
known as the seed coat, or testa (Fig. 
314). The development of this testa 
hermetically seals the structures within, 
further development and activity are 
checked, and the living cells pass into 
the resting condition. This protected structure with its 
dormant cells is the seed. 
The organization of the seed checks the growth of the 
embryo, and this development within the seed is known as 
FIG. 314. Pine seed. 
FIG. 315. Pine seedlings, showing the long hypocotyl and the numerous cotyledons, 
with the old seed case still attached. After ATKINSON. 
