THE SEED AND ITS GERMINATION. 11 



which, are not too thick to become useful leaves, and so the 

 plant is in no special haste to get ready any other leaves. 

 The plumule, therefore, cannot be found with the magnifying 

 glass in the unsprouted seed, and is almost microscopic in 

 size at the time when the caulicle begins to show outside of 

 the seed-coats. 



In the bean and pea, on the other hand, since the cotyle- 

 dons cannot serve as leaves, the later leaves must be pushed 

 forward rapidly. In the bean the first pair are already well 

 formed in the seed. In the pea they cannot be clearly made 

 out, since the young plant forms several scales on its stem 

 before it produces any full-sized -leaves, and the embryo 

 contains only caulicle, cotyledons, and a sort of knobbed 

 plumule, well developed in point of size, representing the 

 lower scaly part of the stem. 



