■IIMKW'IWl 



The Grain of Wheat 



pea ; but to make up for this, their cotyledons 

 are very large. On the other hand, buck- 

 wheat, chickweed and ivy, which have small 

 cotyledons, are supplied with it. Generally 

 speaking, the cotyledons and the perisperm 

 have a similar office : they supply each other's 

 deficiencies in feeding the young plant. As a 

 general rule the seed with large cotyledons 

 has no perisperm, and the seed with small 

 cotyledons is provided with it. 



Many plants have only one cotyledon, and 

 this most frequently is a very small one. 

 It is in these that we find the perisperm. The 

 grain of wheat is one of the most remarkable 

 of these. If we cut this seed lengthways and 

 examine it with the microscope, we shall find 

 at the base, and on one side, the germ which 

 forms a very small part of the seed. Above 

 this is the one cotyledon, which will provide 

 the first, or seminal leaf, and next to this the 

 gemmule, from which the following leaves 

 are produced. At the opposite end there is 

 a short projection — the radicle, the origin of 

 the root. Suppose we compare the tiny 

 cotyledon of the wheat with the two huge 

 cotyledons of the almond. The latter, with 

 their rich supply of food, are well able to 

 feed the growing shrub until the roots are 



239 



