:;:,<> 



MR. J. G. BAK1R ON THE GEOGRAPHICAL DISTRIBUTION OF FERNS 



levels of the Andes, the forests of their slopes and ravines, and the dense humid flats 

 that border the innumerable branches of the Amazon, where the sun's rays and the wind 



penetrate the recesses of the primeval jungles, and climbers and parasites contest 

 the leaves of bright-flowering trees for the possession of the branches, that we obtain 



Timer 



t\ 



e great concentration of species. Our list for tropical America contains 946 species, 



t2 per cent, ol* all that are known; and of these more than three out of four are quite 



peculiar to it. And as by gradual degrees, as traveller after traveller brings or sends to 



Europe the result of his explorations, our knowledge of the distribution of the species is 



increased, U\ o points are more and more brought out into prominence — that all this vast 



constitutes, in any broad 



of the term, but 



sinsie and indivisible Pern 



It 



region, and how prominently individuaHzed the characteristics of that region are. 

 has one Pern out of every three that are known in the world quite peculiar to itself; and 

 yet a very considerable proportion of these reach from Mexico and the West-Indies on the 

 north, to Peru and the south of Brazil; and how completely the West-Indian Islands 

 form part of the same region may be judged from the fact that whilst they yield upwards 

 of 400 species, and have been much better explored than the adjacent parts of the con- 

 tinent, only one species in seven has not been gathered on the mainland; and for the 



• iilapagos group we know clearly only 



mainland. 



species which does not occur upon the 



Torrid Zone. — Taking the Torrid zone as a whole, we find that it yields 1901 species, 



-5 per cent, of th«' whole Order, and that of these 1437 species 65 per cent, of the Order 



are peculiar to it, upwards of 1000 species being confined to tropical America and 



^lalaya. 



Co pre liens ice A 

 the districts. 



8 ix districts, 15 : 



The following are all the species that grow in more than half 



Lorn 



Hymenophyllum polyanthos, Trichomanes radiccms and rigidum 



ttenuata, Aspl 



themum, bulbiferum, and umbrosum, Nephrodiwm 



Thelypteris and spinnlosum, Nephrolepis acuta, Poly podium vulgare, Gymnogramma lepio 

 phy/h, Vittaria lineata, Acrosticlnim conforme, Botrychium Imnaria. 



Seven districts, 12 



Jlymenophyllum Tunbridgense, Adiantum Capillus-veneris, Pel 

 gercmiafolia, Pteris hngifolia, incisa, and cretica, Asplenium Trichomanes and fur 

 Nephrodiwm unitvm and niolle, Polypodium punctatum, Osmunda regalis. 



Eight districts, 2 

 Kine districts, 3 

 Ten districts, 2 : 



Adiantum athiopicum, Nephr odium filix-mas. 

 Pteris aquilma, Asplenium filix-foemina, Ophioglossum mlgatim 

 Cystopteris fragilis, Aspidium aculeatum. Total, 34. 

 In the tropics 64 species belt the globe, in the north temperate zone 34, in the south 



tempe 



Ni nety 



species grow both north and south of the trop 



> 



of 



which the following 26 have a range of 70 degrees of latitude 



Hymenophyllum polvanthos 

 Tunbri (license. 



Trichomanes filicula. 

 pyx id i to rum. 



rigidum. 



Adiantum Capillus-veneris 



rethiopicum. 

 Pteris aquilina. 

 Asplenium Trichomanes. 



monutitbemum. 





