Ferns 235 



to the genera Hymenophyllum, Todea, and Trichomanea. Owing to the 

 peculiar atmospheric conditions necessary for their successful culture, 

 Filmy Ferns are not a very marketable commodity. They are wonderfully 

 beautiful and elegant in appearance, the fronds in many cases resembling 

 the more delicate and more finely divided kinds of green seaweeds. Most 

 of them must be grown in close cases in a cool atmosphere that is always 

 highly charged with moisture. They are planted in a mixture of fibrous 

 peat and loam to which some sphagnum moss and a little broken charcoal 

 are added; and they are usually planted in a kind of rockery made of 

 pieces of rock. Several kinds, however, do well when tied to pieces of 

 tree-fern stem or blocks of peat, more especially those having more or less 

 creeping rhizomes. Water is best applied carefully to the rocks or pieces 

 of stem on which the plants are growing, and the fronds may be " dewed " 

 occasionally with a fine spray from the syringe. The best-known kinds of 

 Filmy Ferns are Hymenophyllum tunbridgense, Trichomanes radicans, 

 (the Killarney Fern), and Todea superba (fig. 317). 



