234 



The Journal of Heredity 



means the relative dominance of one or 

 more factors or character-units of the 

 parents. Gartner, not having the 

 knowledge which has come since and in 

 consequence of Mendel's investigations, 

 sought a theoretical explanation for 

 this phenomenon of dominance and 

 gave it the designation of "sexual 

 affinity)' (Wahlverwandschaft) in the 

 crossing of species, the magnitude of 

 which he considered could be measured 

 by the number of viable seeds produced 

 in the cross. Gartner seems to confuse 

 the matter by appearing to indicate that 

 there might possibly be a different num- 

 ber of seeds produced by the reciprocals 

 of reciprocal crosses, thus presumably 

 indicating a possible "prepotency," so 

 called, of one of the parents in the cross. 

 In other places he simply seems to mean 

 the relative influence, so to speak, of 

 such and such species when crossed with 

 others. This appears to be the mean- 

 ing in the following : 



"This manifestation of generic types, 

 according to which one species acts in 

 a predominant manner over several 

 other species in hybrid breeding, is 

 a further uncontradictable proof that 

 the relationship of the forces, through 

 which the union of two pure species 

 takes place, must be unlike, and that 

 thereby there can be no question of any 

 balance of factors" (p. 290). 



It will be seen that Gartner's view of 

 hybridization was that "species" was 

 crossed with "species" as such, each 

 species as a whole exerting its own rela- 

 tive power or potency in the cross — the 

 hybrid being regarded as the resultant, 

 so to speak, of the contest for supremacy 

 of the two competing natures in the 

 compound. This view is well enough 

 expressed in the following passage: 

 "Thus, just as there are species in a 

 natural genus, which possess a pre- 

 potent fertilizing power upon several 

 other species of their genus, so there are 

 also species which exert upon several 

 others such a typical predominating 

 effect, not to an equal extent, to be 

 sure, but still of such a nature that their 

 operation, in all combinations, is to be 

 recognized by a character in common. 



Both of these forces are, however, of 



different kinds and follow different 

 laws" (p. 289). 



Gartner did not realize, in spite of 

 Sageret's experiments, that some indi- 

 vidual characters of a parent might be 

 found to dominate in a cross and others 

 not. "The laws of hybrid types orient 

 themselves, not toward the individual 

 organs of plants — do not apply to a sin- 

 gle part, e. g., stems, leaves, etc. — ^but 

 are applicable rather to the inner na- 

 ture of species. The organs which de- 

 termine the types of hybrids must 

 therefore be investigated and compared 

 in their totality and in their mutual 

 inter-relationship. For the most part, 

 the individuality of a hybrid expresses 

 itself in its entire habit, but in this re- 

 spect the flower, above other parts of 

 the plant, is most frequently and 

 plainly distinguished" (p. 251). 



Gartner made some crosses with corn 

 and with peas to determine the question 

 of the immediate influence of the pollen 

 upon the character of the seed. In 

 com he got no results, because of cross- 

 ing white com with red, in which latter 

 the color, being due to the skin or peri- 

 carp, does not show until the seeds of 

 the following season ripen. In peas he 

 crossed four varieties. In certain 

 crosses, e. g., Paris Wax (yellow) X 

 Sugar Pea (greenish-yellow). Early 

 Green Brockel (green) X Paris Wax 

 (yellow), and Sugar Pea (greenish-yel- 

 low) X Dwarf Creeping (yellow), the 

 yellow color dominates over the green 

 in the hybrid seeds. 



Gartner's work is noteworthy, not 

 only for the remarkable number of spe- 

 cies with which he experimented but 

 for the scrupulous care which he exer- 

 cised in his operations, if we may judge 

 from his own statements; as, for in- 

 stance, the following: 



"For complete assurance of the purity 

 and reliability of the products of hy- 

 brid breeding, and for testing the con- 

 clusions derived therefrom, we have 

 repeated most of the experiments, espe- 

 cially the doubtful cases, not once only, 

 but several times, and put them to the 

 test through crossing of the same spe- 

 cies, for even with the most scrupu- 

 lous foresight and precision, individual 



