PLANT HYBRIDIZATION BEFORE MENDEL 57 



single capsule. Of a cross between a Dianthus plumarius, which 

 Gmelin had brought from Siberia, a plant with snow-white fringed 

 petals, and D. chinensis^ a plant with single flowers, unf ringed, 

 scarlet-red, with black-red circle, it is stated : 



"in size, as generally in all details, they showed exactly the mean be- 

 tween those of the male and female." (p. 224.) 



From a cross between Dianthus harhatus and chinensis selfed, 

 three plants were produced, all different from one another. To 

 Kolreuter's mind the matter is regarded thus : 



"So much in the meantime is quite clear, that the self-fertilization of 

 such hybrids must go on dissimilarly, and not in an orderly manner, 

 since it even appears as though thereby sometimes a basis were laid for 

 misbirths, as is manifested by, the dwarf stature of the second plant of 

 the present, and of the two hybrids of the thirty-seventh experiment." 

 (P- 233.) 



Kolreuter states that a no less amount of difference showed 

 itself among a few plants of the reciprocal cross, to which he 

 refers as being reported in the second "Fortsetzung," Sec. 26, 

 p. 106. The reference cited, however, is to the selling of a cross 

 between Diaiithus chinensis X carthusianorum. 



Kolreuter also states (p. 236) that he had previously taken the 

 complete similarity of hybrids in reciprocal crosses, as an infal- 

 lible indication of the equilibrium existing between the two fer- 

 tilization elements, but that one must take this principle in a 

 limited sense. The similarity of reciprocal crosses proves incon- 

 trovertibly, that in both cases throughout, the same proportion 

 existed in the mixture of the fertilization elements, but not at 

 all that in every particular case, in respect to mass or activity, 

 an equal amount of each is used in fertilization. As for example, 

 in crossing a blue with a yellow color, a third or green color is 

 produced in a certain definite degree, whether the blue is mixed 

 with the yellow or the yellow with the blue. 



"This green color," he says, "will not exactly, however, on this ac- 

 count, hold completely the mean between the two ground colors, and 

 consequently be distinguishable from that which comes out when one 

 has mixed ten parts of each with the other. In this connection one must, 

 however, pre-suppose that both ground colors are of like activity, for 

 if, for example, the yellow were by one-tenth more active than the blue, 

 yet nevertheless in the given case, irrespective of the unlike proportion 

 in the mass, a medium color would come out, to which each of these 

 ground colors according to its activity contributed equally much." 

 (P- 237.) 



