SPERMATOPHVTES : GYMNOSPEEMS 



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. 



