36 THE BOOK OF NATURE STUDY 



Cotyledons are folded very variously in different seeds. The 

 long, narrow cotyledons of the Sycamore are applied face to face, 

 rolled up in a ball, then as they emerge from the seed they unroll 

 and spread out. With the Sycamore may be compared the Beech. 

 The bracts forming the cup of the Beech-nut generally dehisce 

 into four pieces, enclosing usually two fruits. In each fruit two 

 ovules begin to be formed, but generally only one develops. The 



FIG. 20. Seedling of Sycamore and Beech, with cotyledons and foliage-leaves. 



seed is not large, and the cotyledons are soon too big for it and 

 become folded, not rolled up. 



With regard to the presence of endosperm, it may be stated that 

 if the cotyledons remain in the seed and do not come above the 

 soil, the seed is generally exalbuminous, for the young seedling 

 gets food from the cotyledons. These fill the whole seed, as in 

 the Bean and Walnut. 



Not only are the cotyledons of plants very different from each 

 other, but they are very different from the foliage-leaves that 

 follow. Here again the Beech and Sycamore maybe compared. The 



