BOTANY 



860 



BOTANY 



FOUR OF THE VALUABLE PLANTS THAT STORE FOOD 



win expressed it, must be reckoned with. For 

 plants as well as animals have to fight for a 

 chance to live, and only the strongest and 

 those best fitted for life under the conditions 

 among which they find themselves manage to 

 exist. 



One of the things plants have to fight is 

 overcrowding. So many little plants spring up 

 close together that all cannot possibly find 

 room to grow and food enough to make them 

 strong. Every farmer knows this and is- 

 guided by it, for if he sows his seed too thickly 

 the plants must be thinned out as soon as they 

 show above the ground, or few of them are as 

 strong as they should be. Everyone has noticed 

 how many tiny trees often spring up under 

 the parent tree where the seeds have been 

 dropped, but comparatively few of these, and 

 those the strongest, ever grow up. 



Changes in the climate or moisture condi- 

 tions are other enemies of plant growth. Cer- 

 tain plants need much moisture, and if for any 

 reason the water in a locality grows less and 

 less and finally is gone entirely, these moisture- 

 loving plants must die; swamp vegetation is a 

 definite type which is destroyed when a marsh 

 or swamp is drained. On the other hand, land 

 plants frequently suffer from flood conditions. 

 In the late spring untimely frosts kill off mil- 



lions and millions of little plants which are still 

 too feeble to resist the cold, and the first frosts 

 of autumn prevent many a plant from ripening 

 its seed. 



Animal enemies, too, are numerous and in- 

 clude not only cattle, sheep and other grazing 

 animals, but smaller and still more deadly foes 

 the locust, chinch bug and other insects. 

 Whole crops in various parts of a country are 

 destroyed by these insects every year. (See 

 INSECTS, and each pest named above.) 



Through these and other agencies it comes 

 to pass that the earth is not a jungle like that 

 of the Amazon a jungle so dense that men 

 and animals could not find their way through. 

 In the long run, though vegetation may be 

 luxuriant one year and sparse the next, the 

 growth and the dying-out just about balance, 

 so that if left to itself vegetation remains fairly 

 constant. Man, by his deliberate efforts, can 

 do much to change this; he can cut down cen- 

 turies-old forests and so cause all the surround- 

 ing region to suffer, or he can till and plant 

 barren stretches until "the desert shall rejoice, 

 and blossom as the rose." See FORESTS. 



For a discussion of the structure of plants, 

 the functions of their different parts, and the 

 way they grow, see BUD; FLOWERS; LEAVES; 

 SEEDS; STEM. 



Botany for Older People 



The botanist or the serious, mature student 

 finds in the science far more than a series of 

 loosely-connected, interesting facts about flow- 

 ers and trees and weeds. His botany includes 

 the study of every plant form that grows, from 

 the tiniest bacteria that can be seen only with 



the aid of a microscope, to the gigantic trees 

 whose "slender tops are close against the sky." 

 In fact, so wide is the study that it might be 

 described as a group of sciences rather than as 

 a single one. There is morphology, perhaps 

 the fundamental branch, which deals with the 



