Eversportlng Varieties with Heritable Fasciation. 509 



therefore we can not directly see whether both races or 

 only the first grow in the particular locality; but their 

 great rarity points to the mixed condition. 



The heritable races which have hitherto been found 

 and isolated in this way, behave like eversporting vari- 

 eties inasmuch as each generation consists both of fasci- 

 ated individuals and of atavists, even under conditions 

 of the most stringent selection. Moreover the proportion 

 of these two types appears to be pretty constant, at least 

 under similar conditions of life. As a rule, there are 

 about 40% fasciated individuals and 60% atavists. Higher 

 percentages of the former occur only under favorable 

 circumstances, whilst the proportion of the latter very 

 easily increases under unsuitable conditions of culture, in 

 spite of selection. 



The first instance that I shall describe was afforded 

 by Crepis biennis, an exclusively biennial plant, fasciated 

 • stems of which have been frequently observed in various 

 localities in Holland. The starting point of my culture 

 consisted in two fasciations, which I found in May 1886, 

 in a meadow near Hilversum, amongst hundreds of 

 normal plants of Crepis. The broadening of their stems 

 was small and limited to the top. I collected ripe seed in 

 this meadow in June, but from normal plants only. 

 Whether all or only some of these belonged to the ever- 

 sporting race I was in search of could, of course, not be 

 determined then. 



This seed furnished in the following year about one 

 hundred plants, of which three were already fasciated 

 in the rosette stage, whilst in the following year nine 

 more of them developed more or less flattened stems or 

 branches. The total proportion, therefore, was 12%. 

 In order to make perfectlv sure, T retained only the first 



