156 THE AMERICAN BOTANIST 



plants have inhabited this unstable and changing earth, a cer- 

 tain amount of change must have occurred in them also. 

 Everybody must be aware that no two objects in nature are 

 exactly alike. There is indeed, more or less variations in 

 plants of the same kind and the plant breeder has taken ad- 

 vantage of this to produce a long line of improved varieties of 

 garden vegetables, flowers and fruits. 



Left to themselves, plants must have worked out some 

 similar methods of improvements, for given the power, which 

 all flowering plants possess, of producing seeds far in excess 

 of the number necessary to replace those annually lost by death, 

 there is certain to be an over-production of young plants and 

 consequently great competition for every square foot of avail- 

 al)le space. Only those plants whose natural variations give 

 them some advantage over the others could possibly hold their 

 own under such circumstances. The less nicely adjusted to 

 the locality would naturally perish and leave no sign. In fact 

 we may see this very struggle going on in our own gardens 

 and waste lands every growing season. Millions of young 

 plants spring up, only to be ruthlessly smothered out in their 

 infancy by a few stronger and thriftier individuals who have 

 the ability to take and the power to liold. Thus does Nature 

 [)lay into the hands of the more efficient individuals. 



Considering these facts, one perceives that the resem- 

 blances he notices among plants are not mere accidents. Here, 

 as elsewhere among living things, resemblance denoted rela- 

 tionship. The different forms have descended from a com- 

 mon ancestor and those which most closely resemble one 

 another are most closely related. As in human families, plant 

 children resemble their parents, first cousins may have many 

 family traits in common and these traits somewhat dimmed by 

 distance may appear in second cousins and others more re- 



