305 



VIII. On the Geographical Distribution of Ferns. By J. G. Baker, Esq., F.L.S. 



Head April 4th, 1867. 



1 HERE is no extensive natural Order with the distribution of which we are nearly so 

 well acquainted as we are with that of the Perns. Their beauty and the popularity 

 which they have enjoyed for the last twenty years has been such that all travellers in 

 distant countries who have collected plants at all have paid a full share of attention to 

 Ferns amongst the rest, and that many have neglected flowering plants altogether to 

 concentrate their attention upon Ferns alone. The consequence is, that we now know 

 so much about the distribution of the Order in the various parts of the world, that it is 

 not likely that further discovery will modify materially our ideas of its general outlines. 

 I do not know that any definite attempt has been made to reduce into systematic order 

 the great body of information upon the subject which has been gradually accumulated ; 

 but, in the interests of that department of inquiry for which we still want one general 

 comprehensive name (the study of the facts of the distribution of organized beings over 

 the surface of the globe, and the laws which regulate those facts), it seems very desirable 

 that such a classification should be attempted, especially for this reason, that if anywhere 

 we may hope to find a large Order with distinctly marked and clearly definable climatic 

 relations, it is here. Without a single prominent exception, we find that the whole Order, 

 of between two and three thousand clearly marked species, requires shade and a damp 

 atmosphere, that everywhere within the tropics there are no Ferns at all (or very few) in 

 the dry countries and provinces, that, with the precision of an hygrometer, an increase 

 in the fern-vegetation (it may be in species, or it may be in the number and luxuriance 

 of individuals, but usually in both) marks the wooded humid regions, and that, reading 

 from the tropics, although with latitude the species diminish in number there .s the 

 same contrast between the two categories of climate-the dry continental type with a 

 large, and the damp insular type with a small hiberno-SBstival range My aim, therefore, 

 in the present paper is to bring together the leading facts of fern-dispersion in a form 



available for comparison and f^ .^^ (now in the preS s, planned and 



In the accompanying Table the Synop ^c K entrusted 



commenced by Sir William Hooker, which I have had the > honour oi ^ , 



ic n jn , • i fnr «hi«h is now all prepared) has been followed implicitly 



o carry on, and the material for which is now a p P ) ^ ^ ^ 



for nomenclature and species-limitation As ^ ^ ^^^ te inf< ^ tion| and 

 we have included only the species respecting which we poss^ «dafint 



have wished and intended to retain as ^ J*^ " , an LLum of fifty 



application of this last test, ^ l ^^^^^iTr^^ by the leading 



thousand specimens, a large ^P^/^ST^. which haVe been pub- 

 writers on the subject, and a collection of the plates on 

 Hshed which is complete for all practical purposes, has been to reduce the number 



VOL. XXVI. 



