M. C. Rayner 185 



The experimental results may be tabulated briefly as follows : 



Crested x Type 



Fi , 20 seeds, of which the majority germinated giving 

 plants exactly like the pollen parent. 



Fi selfed. -Fi crested. 



I i 



F-i , 200 seeds, of which 89 reached 12 seeds, none of which germinated, 

 maturity giving plants exactly 

 like parents : no trace of ' crest- 

 ing.' 



The experiments are obviously incomplete and must be repeated 

 and extended before exact hypothesis can be founded upon them. 



The mortality among the Fq generation seedlings may be significant 

 or may be accidental : it requires investigation and analysis and there 

 is at present no evidence as to its cause. 



It is conceivable, for instance, that the seeds carrying the " crested " 

 character are not viable or die off soon after germination. This would 

 account for the non-appearance of " crested " plants under experimental 

 conditions and also for their absence in a wild state. 



Such a hypothesis, however, offers no explanation of the apparent 

 non-inheritance of the " crested " character wheij the variety is selfed. 



If, on the other hand, the mortality was due to accidental causes and 

 the " crested " character is never inherited by seedlings, the possibility 

 that the original plant was of the nature of a periclinal chimaera 

 suggests itself as an explanation. 



Microscopic examination of the epidermal tissues of the two parents 

 has not yielded any evidence in support of this view, nor is it easy to 

 imagine how a plant of this constitution could have arisen in the first 

 instance. The possibility is being experimentally tested. 



The case seems to be worth recording at this stage if for no other 

 reason than to put on record the appearance of a well-marked and 

 apparently isolated case of leaf- variation in a wild plant. 



A tendency to excessive marginal growth of the leaves resulting in 

 the " crested " or " crisped " habit is common among ferns and not 

 uncommon among Angiosperms and in the former it is often inherited 

 by the sporelings. 



There is no record, as far as I have been able to ascertain, of such a 

 general tendency showing itself in Teucriiim Scorodonia, in which plant 

 it seems to have manifested itself as a sudden and rare variation. 



University College, 

 Reading, 



November 1917. 



