YESTERDAY AND TO-DAY 29 



there are quite as many species, and that these 

 are as varied, to-day as has ever been the case. 

 The size of Ferns, as we have already seen, 

 varies enormously. In the tropics and in 

 Australasia there are Tree Ferns eighty feet in 

 height, whilst with many of the Filmy Ferns 

 the size is scarcely larger than that of Mosses. 

 Owing to the fact that it is so necessary in 

 the scheme of reproduction, the majority of 

 Ferns are lovers of moisture. None the less, 

 a few specimens have adapted themselves 

 marvellously to drier conditions. Thus the 

 Bracken will grow on the exposed hillside or 

 cliff-top even where its rhizomes cannot carry 

 the roots to a great amount of moisture. Some 

 of the most interesting species of Ferns are 

 those which grow on walls and rocks, where 

 there is little dampness, during the summer at 

 any rate. Many of these have adopted special 

 devices to cope with drought, such as are to be 

 seen in the Scaly Spleen wort. Here the under- 

 side of the frond is covered with hairy scales, 

 and in dry weather the leaves roll up so that 

 the well-protected underside is alone exposed 

 to the sun. After all, however, Ferns are 

 most at home where there is a comparatively 

 deep shade with abundance of moisture. Many 

 species which will grow in somewhat dry 

 situations attain a much finer development 

 under happier conditions. 



Luckily many kinds of Ferns are still very 

 common in the United Kingdom. Of course, 

 in much- visited localities the ravages of the 

 trippers have practically exterminated some 

 interesting species in these particular districts. 

 Naturally, one hardly expects to find the Royal 

 Fern flourishing to any extent in the popular 

 holiday haunts none the less, there are still 



