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blood appears to confer vigour and has probably been the 

 main cause of the preservation of the variety, which would 

 otherwise not have survived the vicissitudes to which it has 

 been exposed. The feature of polydactylism has also 

 crossed over from P. angulare to P. aculeatum, this being 

 first effected by a deliberate and purposive sowing on the 

 part of Mr. E. F. Fox. A later example is the manifesta- 

 tion in P. aculeatum pulcherrimum of an imperfectly poly- 

 dactylous form, this being a seedling raised by Mr. Cran- 

 field. This form at times seems to promise well but as a 

 rule the fingered character is too irregular and fugitive to be 

 considered anything other than a defect from the ornamen- 

 tal point of view. Nevertheless the plant is interesting 

 biologically because it was not the result of an intentional 

 cross at all and it may possibly be a manifestation of 

 simple ' ' sporting " on the part of the parent pulcherrimum. 

 Other cases have given rise to the suspicion that there may 

 be an inherent tendency in the Polystichums, and especially 

 in the more complex forms to put on this character when 

 propagated from spores. A sowing of my own, in which 

 the polydactylous strain was carefully avoided, rather 

 supports this view, but it must be confessed that this kind 

 of sporting — if sporting it be — was absolutely unknown in 

 these species until intentional crosses had been effected. 



[To be continued.] 



