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specific difference suflicient to set them apart as other than' 

 merely varietal forms, and yet they had received separate 

 specific names. 



This seems to me to constitute fair evidence that it is 

 a great mistake for the botanist to ignore, as he generally 

 does, the study of what mere variation can do to transform 

 one and the same species by simple " sporting " or 

 "mutation." A true species should present some other 

 character than mere diversity of type of frond. To take 

 Polypodiuui vulgave as an example, there have been found 

 in Great Britain scores of constant varieties, in which the 

 form of the frond is in some cases so diversified as lo 

 render the difference between them much greater than that 

 between recognised specific forms of the same genus. 

 They all, however, agree exactly in the type of rhizome and 

 the fructification when fertile, and that I think should 

 determine their rank as '' sports " of one and the same 

 species, and not different ones entitled to rank as separate 

 species. There are, however, converse cases. Thus, 

 for instance, we have the exotic Polysticlmiii setosuni, which 

 some botanists rank as a form of P. aculeatuui. Here on the 

 other hand we have a perfectly distinct species. It shows 

 a setose or bristly character, which is never seen in 

 P. aculeatuui despite its very variable character, and hence 

 to my mind it is justly entitled to specific rank. Put the 

 twa species side by side, and no one could confound the 

 two, so great is the difference in appearance of P. setosum 

 in width of frond, brighter colour, lucency of surface, and 

 above all, ths setose character which pervades it, and 

 gives it its specific name. It would be a good thing if 

 some of those botanists who devote their time to the study, 

 reform, and simplification of nomenclature, and on the 

 strength of the theory that the first name given should be 

 the one adhered to, are constantly digging such out from 

 ancient and often most unreliable records, thus adding 

 to the legion of useless synonyms which are the bugbear 



