FERN STATISTICS. 335 



perty in the elegant tribe, their predilection for warmth 

 and moisture. In cultivation it is found that most of 

 our native species respond to a little cosseting in these 

 particulars ; and in the germination of the spores and 

 the forwarding of the early development, perhaps all 

 are sensibly benefited by such means. Islands in the 

 tropical regions present these conditions in highest 

 combination; and it is in such places that ferns 

 chiefly abound. Clare and Kerry in Ireland, and 

 Devon and Cornwall in England, are the regions 

 which make the nearest approach to the conditions of 

 a tropical island, stretching out as they da into the 

 ocean towards the south-west. 



Statistical calculations have been made by botanists 

 which curiously illustrate this tendency. In Egypt 

 there is but 1 Fern to every 970 flowering plants ; in 

 Greece, 1 to 227 ; in Portugal, 1 to 116 ; in France, 

 1 to 63 ; in England, 1 to 35 ; in Jamaica, 1 to 9 ; 

 in the Sandwich Isles, 1 to 4 ; and in Eaoul, a little 

 island in the South Pacific, 1 to 1, the Ferns forming 

 actually half the vegetation; so that every second 

 plant is a Fern.* 



* Dr Hooker, " On the Botany of Raoul Island," in the Proc. 

 Linn. Soc., vol. i., p. 125. Some observations of interest on the 

 geographical distribution of the ferns in this island I quote : " The 

 absence of any ferns (with a single exception) but such as are natives 

 of New Zealand, is a very striking fact, both because the list is a 

 large one for so small an island, (twenty-two species,) and because, 

 if their presence is to be accounted for wholly by trans-oceanic trans- 

 port of the species, the question occurs, Why has there been no 

 addition of some of the many Fiji or New Caledonia island-ferns, 

 that are common tropical Pacific species, the Fiji Islands being 



