FILMY OR TRANSPARENT FERNS. 



79 



The quantity of light to be given to Filmy Ferns has also been a subject 

 of much controversy, as for a long time they were invariably grown in very 

 dark places ; but, thanks to the experiments successfully conducted, regardless 

 of expense, by Mr. J. Cooper Forster, we are now in possession of a much 

 sounder knowledge of the subject. At Upper Grosvenor Street, where, as 

 before stated, he grew these plants to perfection, it was proved that, although 

 Trichomanes radieans is occasionally seen growing wild in positions so dark 

 and so gloomy that its fronds are scarcely discernible, the place best adapted 

 for its culture, as, indeed, for that of other Filmy Ferns, is a spot where good 

 light, with absolute protection from every ray of sunshine, can be secured. This 

 is borne out by the fact that the strongest and the most numerous growths 

 all make their way towards the light. When Mr. Forster's collection of 

 Filmy Ferns was at its best, its fortunate possessor was particularly fond 

 of showing a large patch of Hymeno'phyllum Tunbridgense, part of which was 

 in the shade and part in the light, and of letting his visitors draw their 

 own conclusions ; for, while the portion in the shade gradually dwindled 

 away, that in the light increased in thickness, and the fronds gained in 

 length, many of them measuring fully 4in., which is not a very usual 

 occurrence among cultivated plants of that species. 



Contrary to the Todeas, all of which produce their handsome, feathery 

 fronds from an indivisible crown, nearly all the Hymenophyllums, and also 

 the greater part of the Trichomanes, in cultivation are of trailing or creeping 

 habit, and are provided with rhizomes which, in some cases, have the power 

 of firmly adhering to rocks or other material with which they come in 

 contact, as is the case with Trichomanes radieans and its varieties ; Avhereas 

 in others, such as in nearly all Hymenophyllums, they simply trail loosely on 

 the ground as if devoid of all power of adhesion. The materials required for 

 growing Filmy Ferns vary according to the nature of the roots and rhizomes 

 of the different species ; indeed, the soil is only a matter of secondary 

 importance, as it has been found that almost any material, if sufficiently 

 porous, free from impurity, and possessed of moisture-retaining qualities, is 

 suitable for their growth. As a rule, the species with thin, wiry rhizomes 

 are averse to having them deeply buried, and delight in running through 

 partly-decomposed moss and other vegetable matter ; whereas those with 

 thick, fleshy rhizomes are particularly fond of sandstone or of any other 



