How Plants Perpetuate Their Kinds 297 



but such is the fact, and such dominance of one character over 

 another is always a feature of Mendelian inheritance. 



Now this remarkable distribution of contrasting characters is 

 true not of the cotyledon color of Peas alone, but of their flower 

 colors, their height, and other characteristics; and not of Peas 

 alone but of innumerable other plants, and likewise of the most 

 diverse animals, in the most diverse characters. Moreover, while 

 discovered and most conspicuous in hybrids, it is also true in prin- 

 ciple of all kinds which breed together; and while its mathe- 

 matical basis can be traced clearly only in self-fertilizing forms, 

 it holds true, though of course with proportional complications, in 



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I 



000 



ri i i i i i i n i i PI i 

 oooo ooo* ooo 



FIG. 105. A diagram illustrating Mendelian inheritance. It is fully explained in the text. 



cross-fertilized forms. There is, indeed, no longer any doubt that 

 it represents a very wide spread principle of heredity. Indeed, 

 were it not for the numerous complications introduced by the 

 complexity of life-phenomena, it would probably be found to hold 

 true universally. 



Mendel's discoveries have thus shown not only that heredity is 

 correlated with a certain mathematical principle, but also that 

 any undesirable feature can be rapidly and surely bred out of a 

 race, and need not require the slow process of dilution out, so to 

 speak, as was formerly supposed. 



There is one fact about this Mendelian distribution of characters 

 which will illuminate the whole subject greatly if the reader will 



