THE OTHER BRITISH FERNS 



It is also desirable to look for genetical evidence regarding the mode of inheritance of 

 spore pattern, before final conclusions are drawn. 



The status of the C. Dickieana-Baenitzn complex would be easier to determine if there 

 were greater uniformity among the spiny-spored forms. These are, however, more 

 diverse than the description so far given suggests. It is true that in Britain and Switzer- 

 land the principal populations have both spiny spores and the high chromosome number 

 of 126, but even in these countries other types can be found, and elsewhere the relative 

 proportions may prove to be quite different. Fig. 119 shows a small assemblage of 







V 



^\ 





^T \^^ 



n -- 126 



Cystopteris n ^ 84 



a b 



Fig. 121. Explanatory diagrams to Fig. 120c and b to show the two chromosome numbers 

 in ^ Cystopteris fragilis'' with spiny spores, x 1500. 



fronds from Britain, Switzerland, Scandinavia and Canada in which rather small 

 spiny spores and the lower chromosome number of 84 have been found. Populations 

 of this type have been met with so far in one place in Switzerland (Preda), in two places 

 in Britain (Rannoch Moor in Scotland and the Lake District), in Iceland (Brekkufjall), 

 in Finland (Piikkio), and over large areas in Scandinavia, specific sites being Runmaro 

 near Stockholm, Storlien in Jamtland, Swedish Lapland, and Trondheim and Hell 

 in Norway. It is probable, indeed almost certain, that the high-numbered form also 

 occurs in Scandinavia, though it is not so distinctly the dominant type there as it is 

 with us. In Canada, on the other hand, the high-numbered form has not yet been 

 encountered, although the low-numbered form has been obtained from Ontario, 

 Ottawa and several places on Vancouver Island (Figs. 120c, 121a). 



Taking the whole evidence assembled to date we have thus detected in a preliminary 

 glance at Cystopteris in Europe, Iceland, Greenland and America three spore types 

 (i.e. large and small spiny spores and verrucose spores), two chromosome numbers 



121 



