46 



THE PLANT. 



CHAPTEE VII. 



LOCATION OF THE DIFFERENT PARTS, AND VARIATIONS 

 IN THE ASHES OF PLANTS. 



LET us now examine plants with a view to learn- 

 ing the location of the various parts. 



The stem or trunk of the plant or tree consists 

 very largely of woody fibre / this also forms a large 

 portion of the other parts except the seeds, and, in 

 some instances, the roots. The roots of the potato 

 contain large quantities of starch. Other roots, such 

 as the carrot and turnip, contain pectic acid* a 

 nutritious substance resembling starch. 



It is in the seed, however, that the more nutritive 

 portions of most plants exist, and here they maintain 

 certain relative positions which it is well to under- 

 stand, and which can be best explained by reference 

 to the following figures, as described by Prof. John- 

 ston : 



PIG. 1. 



" Thus a shows the position of the oil in the outer 



* This pectic acid gelatinizes food in the stomach, and thus 

 renders it more digestible. 



