GERMINATION 



13 



is absorbed and passed on to tho other parts of the seed. The 

 taking in of water causes both embrjo and surrounding food (en- 

 dosperm) to swell and the seed coat to crack lengthwise. The 

 appearance of the radicle through or near the hilum is again 



Ml 



-Different stages in the germination of the sq 



our first evidence of germination, followed bj the elongation 

 of the hypocotvl and the lifting of the cotyledons above the sur- 

 face of the soil very much as in the case of the bean. How- 

 ever, the seed coats persist much longer than in the bean and the 



lai 



Fig. S. — Bean seedling coming through the soil. 



food is gradually absorbed by the cotyledons. As the food dis- 

 appears the cotyledons gradually become green and leaf-like in 

 appearance and function. They usually fall early, but are 

 sometimes retained for a lono- time. 



