548 THE BOOK OF GARDENING. 



decomposed sphagnum is that which satisfies Todeas, Hymeno- 

 phyllums, and Trichomanes, and, indeed, all kinds of "Filmies" 

 with crowns or slender, shining rhizomes which delight in running 

 into loose and decayed vegetable matter. It is best for the soil 

 •to be a little higher in the centre than at the sides. A miniature 

 rockery may also with advantage be worked in the case, and 

 there is no necessity for cementing together the pieces of stone 

 or of tufa used in its construction. Provided that these be 

 firmly embedded in the soil, they need only be stood up, and 

 will easily be held iii position by the soil itself, and by the 

 Ferns planted between them. The case should be placed as 

 near the window as possible, and in preference near a window 

 facing north, as it is most essential that while the Ferns should 

 be protected from the hot sun they should receive all the light 

 possible. 



Watering the Fern-case is an operation which requires a 

 certain amount of tact, as a great deal of irreparable mischief 

 is often the result of a too liberal use of the watering-pot. 

 After being planted, the Ferns should be watered gently until 

 the soil is uniformly damp, and the case being closed, no 

 more water will be required until the surface of the soil gets 

 dry, when a gentle watering over the ground only, as before, 

 should be given to the extent required ; but in any case it is 

 most advisable to keep the foliage of the plant dry, unless 

 the case is planted entirely with Filmy Ferns, which may 

 safely be watered overhead, and should be kept in a moist 

 condition. When grown in a room, the latter require but 

 little ventilation, as it is well known that, if exposed for any 

 length of time to the influence of the dry air of the dwelling- 

 room, their delicate fronds soon shrivel up and are eventually 

 destroyed. A case filled with ordinary kinds of Ferns requires 

 a greater amount of ventilation, and, when thoroughly estab- 

 lished in it, the plants derive much benefit from the change 

 of air, which should be frequently given to prevent the glass 

 from becoming dim and slimy through the condensation of 

 moisture remaining too long upon it. 



Propagation. — The various ways by which Ferns are generally 

 propagated are : (i) by means of the spores ; (2) by the 

 division of the crowns ; (3) by the bulbils, or adventive buds, 

 with which certain species are provided either at the base of 

 their fronds, or at their extremity, like Woodwardia radicans 

 and certain Adiantums and Aspleniums ; along their rachis or 

 midrib, like certain Polystichums ; or again all over the surface 

 of their fronds, as in certain Aspleniums, Scolopendriums, and 

 Woodwardia oriental's. 



Spores. — The most interesting, as also the most rapid mode 

 of increasing Ferns on a large scale, is, undoubtedly, by means of 

 the spores, as it is in flowering plants by means of their seeds. 



