476 On the Latent Capacity for Mutation. 



amount. In 1892 I had, besides 20 tricotyls, 6 henii- 

 tricotyls which however I did not cultivate further. The 

 seeds of each of the former was harvested separately 

 and sown; the best of them gave 2.6 — 2.8% tricotyls, 

 but the majority less than 1.5%. The proportion in 8000 

 seedlings was 0.7% ; there were also 7 hemitricotyls and 

 2 syncotyls. 



In 1893 I planted out 70 seedlings derived from five 

 seed-parents which had given from 1.5 to 2.8% tricotyls. 

 In 1894, however, they yielded a harvest in which the 

 percentage was very low, having sunk, in the case of the 

 best seed-parents, to 1%. I planted out about 90 of the 

 best seedlings, with a view to obtaining seed from them. 

 Besides the above mentioned tricotyls in the crop of 1894, 

 I found several hemitricotyls and a single tetracotyl ; 

 also a considerable number of syncotyls and one amphi- 

 syncotyl or seedling with the cotyledons fused together 

 on both sides. 



This brief resume suffices to show that tricotyly is 

 heritable and that, in my families, it is transmitted from 

 generation to generation even through plants with normal 

 cotyledons, i. e., in a latent state. 



Fasciation. Split and fasciated stems occur almost 

 every year in my Oenothera Lamarckiana.^ The ab- 

 normality usually occurs in the axis of the inflorescence ; 

 very rarely lower down in the stem or in the rosette. 

 Fasciated plants occurred in all my families with a few 

 inconsiderable exceptions ; but, as far as possible I never 

 chose them as seed-parents. 



The "split stem" is, so to speak, the lowest stage in 

 the development of this abnormality, and, consequently, 



^ Over de crfelykheid van fasciatien, in Botanisch Jaarboek Do- 

 donaea VI, 1894, pp. 92 and 95. 



