38 



STRUCTURAL BOTANY 



e.g. Castor-oil seed, Hempseed, Linseed, etc. Oil con- 

 tains the same elements (C, H, 0) as carbohydrates, 



but in very differ- 

 ent proportions, the 

 proportion of oxygen 



being very much 

 less. The oil occurs 

 in the form of small 

 drops embedded in 

 the protoplasm. 



B. Proteid, Granules 

 These form a very 

 important part of 

 the contents of cer- 

 tain cells, especially 

 in seeds and other 

 organs in which 



food is stored up for the use of the plant. They are 

 chemically similar to the substances of which the pro- 

 toplasm is composed, but are themselves inactive, and 

 serve simply as food. An example is shown in Fig. 16, 

 which represents the complex proteid granules of the 

 Castor-oil seed. 



c. Cell-Formation 



Cells increase, in number entirely by division. 

 Every cell which exists owes its origin to the division 

 into two or more parts of some cell which existed 

 before it. At present we will only describe the kind 

 of cell-formation which goes on in the vegetative parts 



FIG. 16. A, Cell from the endosperm of 

 the Castor-oil seed, examined in water ; 

 note the large proteid granules, each of 

 which contains one or more crystalloids 

 (c), also of proteid, and a globoid (g], of 

 calcium magnesium phosphate. B, 

 Isolated granules, examined in olive-oil. 

 (After Strasburger.) Magnified 540 

 tunes. 



S 



