420 Ever-sporting Varieties 



and mercury {Mercurialis annua) among the 

 first, snapdragon, poppies, Phacelia, Helich- 

 rysum, Clarkia among garden-flowers may be 

 given as instances of species containing the rich 

 tricotylous double races. 



It is very interesting to note how strong the 

 difference is between such cases and those which 

 only yield poor races. The rich type at once 

 betrays itself. No repeated selection is re- 

 quired. The stray tricotyls themselves, that 

 are sought out from among the original samples, 

 give hereditary percentages of a much higher 

 type after isolation than those quoted above. 

 They come up to 10 - 20;^ and in some cases even 

 to 40^. As may be expected, individual differ- 

 ences occur, and it must even be supposed that 

 some of the original tricotyls may not be pure, 

 but hybrids between tricotylous and dicotyl- 

 ous parents. These are at once eliminated 

 by selection, and if only the tricotyls which 

 have the highest percentages are chosen for the 

 continuance of the new race, the second genera- 

 tion comes up with equal numbers of dicotyls 

 and tricotyls among the seedlings. The figures 

 have been observed to range from 51 - 58^ in the 

 majority of the cases, and average 55^, rarely 

 diverging somewhat from this average. 



Here we have the true type of an ever-sport- 

 ing variety. Every year it produces in the 



