110 COMPOUND ORGANS OP PLANTS. 



of nutriment, and finally to produce finer flowers and fruit. 

 By removing their flower buds as soon as formed and thus 

 preventing the exhaustion consequent on flowering, annuals 

 may be changed into biennials, or even perennials, their life 

 being prolonged indefinitely; whilst the same plants left to 

 flower in the ordinary course of nature, perish as soon as they 

 flower and bear seed, whether during the first, second, or any 

 succeeding year. The actual consumption of nutriment in 

 flowering, is seen in the rapidity with which the farinaceous 

 and saccharine store accumulated in the roots of the beet and 

 carrot disappears as soon as these plants begin to flower, 

 leaving them light, dry and empty ; so also the esculent roots 

 of radishes and turnips become fibrous and unfit for food, when 

 they are allowed to run to seed. When the branch of a fruit 

 tree is ^sterile, it may be made to flower and fruit abundantly 

 by being girdled. This consists in the removal of a narrow 

 ring of bark from the branch, sufficient to arrest the downward 

 course of the elaborated sap, which is thus accumulated in the 

 branch in a sufficient quantity to produce this desirable result. 



The reproductive organs show themselves only at the epoch 

 when the plant acquires all its development, or arrives at an 

 adult state. The period when this event occurs depends on the 

 peculiar organization of the plant. At this time a change 

 takes place in the primary mode of development, the buds in 

 the axils of the leaves or at the extremities of the branches 

 cease to elongate, and the internodes or naked intervals of stem 

 between the leaves being non-developed, the leaves remain 

 crowded together in whorls, in a sort of rosette, and under- 

 going peculiar modifications in their form and color, a flower is 

 produced. 



Every flower, when complete, consists of four whorls of pro- 



