SEED-BEARING PLANTS 



407 



without undergoing any resting period, until the new sporo- 

 phyte has emerged from the seed and become established 



FIG. 302. Zamia floridana. a, free nuclei of proembryo; X 16; 6, 

 tissue at base of proembryo; X 24; c, differentiation into suspensor and 

 embryo; X 29; d, young embryo showing long suspensor, natural size. 

 (After Coulter and Chamberlain.) 



in the soil as an independent plant (Fig. 303). In its early 

 stages the embryo derives its nourishment as a parasite 

 from the female gametophyte (prothallus, or endosperm). 



