APPENDIX 327 



in ascertaining whether the law of development discovered in these 

 applied to each pair of differentiating characters when several 

 diverse characters are united in the hybrid by crossing. As regards 

 the form of the hybrids in these cases, the experiments showed 

 throughout that this invariably more nearly approaches to that one 

 of the two parental plants which possesses the greater number of 

 dominant characters. If, for instance, the seed plant has a short 

 stem, terminal white flowers, and simply inflated pods; the pollen 

 plant, on the other hand, a long stem, violet-red flowers distributed 

 along the stem, and constricted pods; the hybrid resembles the 

 seed parent only in the form of the pod ; in the other characters it 

 agrees with the pollen parent. Should one of the two parental 

 types possess only dominant characters, then the hybrid is scarcely 

 or not at all distinguishable from it. 



Two experiments were made with a considerable number of 

 plants. In the first experiment the parental plants differed in the 

 form of the seed and in the colour of the albumen; in the second 

 in the form of the seed, in the colour of the albumen, and in the 

 colour of the seed-coats. Experiments with seed characters give 

 the result in the simplest and most certain way. 



In order to facilitate study of the data in these experiments, the 

 different characters of the seed plant will be indicated by A, B, C, 

 those of the pollen plant by a, b, c, and the hybrid forms of the 

 characters by Aa, Bb, and Cc. 



Expt. 1. — AB, seed parents; ab, pollen parents; 



A, form round; a, form wrinkled; 



B, albumen yellow. b, albumen green. 



The fertilised seeds appeared round and yellow like those of the 

 seed parents. The plants raised therefrom yielded seeds of four 

 sorts, which frequently presented themselves in one pod. In all, 

 556 seeds were yielded by 15 plants, and of these there were: 



315 round and yellow, 

 101 wrinkled and yellow, 

 108 round and green, 

 32 wrinkled and green. 



it is very unlikely that Mendel could have had seven pairs of varieties such that the 

 members of each pair differed from each other in only one considerable character 

 (wesentliches Merkmal). The point is probably of little theoretical or practical 

 consequence, but a rather heavy stress is thrown on " wesentlich."' ] 



