imexdel's law of heeedity and hoeticulture. 



29 



pink ' Countess Spencer. '" The diagram (fig. 15) will illustrate how 

 this was done. The plain red variety, ' King Edward,' crossed with 

 the waved pink variety, ' Countess Spencer,' produced in the first 

 generation (Fi) a plain red cross-bred, the lower waved and pink 

 characters not being manifested, owing to the presence of the higher 

 plain and red factors.! 



In the second generation (F2) the plain red cross-bred self-fertilized 

 produced four forms — plain red, plain pink, waved red, and waved 

 pink — in accordance with Mendel's law. 



Mr. Cuthbertson did not apparently count the numhers of each 

 type, but there should have been on the average nine plain reds, three 

 plain pinks, three waved reds, and one waved pink. That is to say, 

 out of every sixteen plants raised, three plants of the novelty ' Waved 



Sweet Pea 



PlA I N 



Red 



WaV t D 



Pink 



Plain 

 Red 



^ 1 



Plain 



RCD 



Plain V\/a v e d \a/a v e d 



P f N K^^^^^..^-^ R E D ^--.,....^^^1 N K 



ll/'a/i/ecC '^K/L/np idjvcurcb 



Fig. 15.~Showing the origin of the ' Waved King Edward ' Sweet 

 Pea by re-combination following Mendelian Segregation. 



King Edward ' would be the Mendehan expectation. On the average, 

 one of these would breed true, while two would throw waved pinks 

 again. By selecting the pure individual Mr. Cuthbertson would thus 

 secure a pure strain of the novelty in the second generation. 



Mr. Cuthbertson states that he raised the novelty ' Primrose 

 Spencer ' in a similar manner. 



In my own experiments a few years ago I raised a true stock oJ 

 * Black Knight Cupid ' in the second generation by crossing the ordinary 

 * Sweet Pea Annual, 1909. 



t From a few results that I have seen it seems likely that when the ' Waved ' 

 or ' Spencer ' type of sweet pea (now so popular with sweet -pea fanciers) comes 

 to be critically studied in its Mendelian relationship to the " plain " and " hooded " 

 types some complications will be found. Indeed, it would not be surprising to 

 hnd that there are at least two genetic types of the ' Waved ' sweet pea. 



