GERMINATION. 13 



be readily detached from the rest of the seed. 

 The seed is monoeotyledonous and careful ex- 

 amination of the detached embryo shows that 

 the single cotyledon does not grow or extend 

 through the seed -coat but forms the means of 

 communication through which the reserve of 

 plant food passes into the young growing 

 plant. The cotyledon, here known as the 

 "tttttellutn" lies upon the surface of the 

 albumen, which in this case consists almost 

 entirely of starch. As soon as germination 

 begins the scutellum secretes a digestive Huid 

 which converts the insoluble starch into 

 soluble substances which are readily absorbed 

 by the scutellum and passed on to the grow- 

 ing plantlet, which lies on, and attached to, the 

 other side of the scutellum. As the starch is 

 dissolved and used up the scutellum presses 

 forward into the vacant space, finally tak- 

 ing up all the starch and leaving the seed- 

 coat empty. While this is going on the young 

 plant is growing in size, thrusting its roots 

 into the soil and its leaves into the air, so 

 that by the time the supply of starch within 

 the seed is exhausted it is able to obtain its 

 own food. 



