300 



THE BOOK OF CHOICE FERNS. 



more or less deeply two-lipped or bivalved, of nearly the same texture as 

 the frond, and either toothed, fringed, or entire. The capsules, which are 

 mostly orbicular (quite or very nearly round), are pressed down, attached by 

 the centre, and furnished with a broad, transverse ring which opens irregularly 

 at the apex and forms a purse-like process. 



A sub-division of the genus was formerly recognised by Presl and by 

 Van den Bosch under the name Leptoclonlum. This was composed of species 

 having fronds more or less divided and spiny, and finely toothed on the 

 edges, either smooth, hke those of H. tunbridgense, or crisped, like those of 

 H. dichotomum. This name, however, has been abandoned by the authors 

 of the " Synopsis Filicum," in Avhich work H'ymenophyllum forms Genus 16, 



Culture. 



To the particulars already given in the chapter on "Filmy Ferns" in general 

 (pp. 73-81 of Vol. I.), we may here add that, as regards Hymenophyllums, 

 with the exception of the beautiful H. fuciforme and II. pidcherrimum, nearly 

 all the species at present known are of creeping habit, and that, being pro- 

 vided with shallow-rooting rhizomes, they succeed best when growing on the 

 surface of a rock and allowed to run under the moss which covers it, as is 

 shown most emphatically by the glorious vegetation noticeable in the truly 

 grand Fernery of Messrs. J. Backhouse and Son, of York. It is also worthy 

 of notice that the great majority of the plants contained in the genus are 

 native of New Zealand, Tasmania, and Chili, where they exist in a climate 

 naturally cool and humid, and of the East and West Indies, where they grow 

 spontaneously under trees at high elevations ; in such situations they are 

 permanently subjected to the influences of shade and moisture, and also to 

 a comparatively cool temperature. 



Hymenophyllums are particularly well adapted for growing in Fern-cases 

 in town ; they are all the more valuable by reason of their fohage, though 

 apparently of a delicate nature, not being, like that of most other Ferns, 

 affected by the London fogs, which prove so destructive to vegetable life in 

 general. This has been repeatedly noticed by the various Fern lovers and 

 growers who give this class of plants preference over all other Ferns. Thus, 

 for instance, it is on record that in north wuidows on the staircase of liis 



