INTRODUCTION. 



5 



India, America, and other parts very distant from one another. From the 

 foregoing examples, to which, but for the want of space, we might add 

 numerous other illustrations, it will readily be admitted that a satisfactory 

 separation of British and exotic Ferns is a matter surrounded with insuperable 

 difficulties. Ferns, it must be borne in mind, unlike most other plants, are 

 found in a wild state all over the globe, and at various elevations. 



Another remarkable peculiarity as regards the distribution of Ferns, is that 

 each country appears to yield plants forming natural special sections. Thus, 

 for instance, the power of producing crested, depauperated, cruciated, and other 

 characters peculiar to forms of original species, either of an evergreen or of a 

 deciduous nature, is much more developed among Ferns growing spontaneously 

 in England than among those found in any other country. Whether these 

 changes are clue to the influence of the atmosphere, or whether they may be 

 attributed to other agencies, the fact remains that scarcely a single species 

 of Fern, native of the British Isles, has retained its normal characters 

 throughout — all have become more or less addicted to variations ; and that 

 power of producing variable forms, which may possibly be a natural 

 predisposition on the part of the said species, can hardly be ascribed to 

 the effects of cultivation, since we find that most of these multifid, crested, 

 and other forms, so numerous especially amongst the Scolopendriums, 

 Aspleniwn Filix-foemina^ Nephrodium, Filix-mas, Aspiclium angulare, and Poly- 

 podium vidgare, have usually been met with in a wild state, comparatively 

 few of them having originated among cultivated plants. To Japan we are 

 indebted for the greater part of our hardy greenhouse Ferns ; and most of 

 these Japanese kinds, such as Aspidiwm setosum, A. falcaturn. Nephrodium 

 erythrosorum, N. opacum, &c, all of which are evergreen and hardy, have a 

 peculiarly glossy appearance and leathery or coriaceous texture, which 

 characters are shared by very few of our own indigenous Ferns, and by 

 scarcely any other exotic kinds. North America supplies us with Ferns 

 mostly of a deciduous nature, the most remarkable of these being Osmunda 

 cinnamomea, 0. Claytoniana (inter rupta), and 0. (regalis) gracilis, Onoclea 

 sensibilis, 0. germanica (Struthiop>teris pennsylvanica), Adiantum pedatum, 

 Dichsonia punctilobula, and Woodwardia areolata. It is singular, however, 

 that although the above-named are Fern- countries in every acceptation of 

 the word, the growth of their indigenous species partakes of an herbaceous 



