360 THE BOOK OF CHOICE FERNS. 



advocate for either Hymenophyllums or Todeas the use of stone, this material 

 is essential to the well-being of certain Trichomanes. 



As will be noticed in the descriptions of the species here given, 

 many of the plants are provided with rhizomes, and these are in most 

 instances of a very different nature from those of Hymenophyllums, as the 

 greater part of them possess a very strongly-marked power of adhesion : it 

 is for these species especially that the stone is necessary. While some of the 

 kinds with slender, though equally hairy rhizomes, such as T. humile, 

 T. pyxidiferum, T. trichoideum, and T. venosum, which in their natural 

 habitats are usually found clothing Tree-fern stems, prefer rambling through 

 decaying vegetable matter, others, also provided with very slender rhizomes, 

 prefer sandstone, or stone of a very porous and soft nature — this is 

 particularly the case with such species as T. Colensoi, T. exsectum, T. parvulum, 

 T. tenerum, &c. It has been noticed, however, that species provided with 

 stout, hairy, creeping rhizomes, such as T. javanicum arid T. radicans, thrive 

 best when in close proximity to stone of a harder nature, to which they will 

 cling with great tenacity. Where necessary these peculiarities will be 

 mentioned with the plants described. It may be well to note here that 

 whenever stone is used it is necessary that a little peat of a sandy-fibrous 

 nature should be placed at its base to establish the plant. 



As regards light, moisture, and ventilation, we need not here repeat what 

 has already been stated in the chapter specially devoted to Filmy Ferns in 

 Vol. I. (pp. 73 to 81), as the particulars there given are all that is requisite 

 for the successful culture of these plants. 



The propagation of Trichomanes is usually effected by division of the 

 rhizomes, although it also sometimes takes place by means of proliferous buds. 

 For instance, T. pinnatum is conspicuously proliferous at the extremity of its 

 fronds, where, when touching the ground, they frequently root of their own 

 accord. In the same way a form of T. radicans, named proliferum, found in 

 Ireland, may be increased by the rooting of the bulbils produced on the upper 

 surface of its fronds. Trichomanes may also be propagated by means of spores, 

 but this is a somewhat tedious process ; in 1886 a batch of several hundred 

 young T. radicans were raised in that way in Messrs. J. Veitch and Sons' 

 nursery at Chelsea, and, strange as it may appear, the species reproduced 

 itself without any noticeable deviation whatever from the normal form. The 



