176 Oranges and Lemons of India. 



teresting genus, as I view it, I shall have to begin at 

 the beginning. 



The citrus tree, like many others, commences its 

 existence by a bud, which is protected from external 

 influences by the seed shells or coverings. It is also 

 protected against starvation during its infancy, and 

 until it perfects its own organs of nutrition, by a small 

 store of food enclosed within the same shells in what 

 are called the cotyledons. Under certain circumstances 

 this bud germinates and starts into growth. Even at 

 this early stage, the stem of the young citrus and its 

 first leaves are studded with essential oil glands. As 

 we shall see in another place, these oil glands may be 

 of importance to the adult plant, but I am not sure 

 that they are not a disadvantage to it while it is a 

 young seedling. Anyhow, I suppose, like all of us, 

 plants and animals, we must make the best of what 

 means we happen to possess, in order to compete suc- 

 cessfully with other individuals. 



It would appear that the leaf of any plant is simply 

 an expansion of the bark. The leaf of the citrus is 

 studded with two or more sets of oil glands, viz. : large 

 ones at certain distances, the intermediate spaces being 

 filled with secondary and tertiary oil cells, as shown in 

 pi. 1 8 1, fig. a. This arrangement is universal, what- 

 ever the variety may be. The edges of the leaves are 

 crenated, that is, shaped like little festoons. In a well 

 developed leaf, the big crenations have smaller crena- 

 tions. The angles formed by the big crenations have 

 each a large solitary oil cell, and the angles formed by 

 the smaller crenations have each a smaller oil cell also. 

 In many orange leaves these crenations are found only 

 towards the tip half of the leaf. In the citrons, lemons, 

 and allied varieties they often commence close to the 

 petiole. There is such a thing, however, though rare, 



