288 



CASSELL'S POPULAE GARDENINa. 



saturation point. Soil, &c., is quite a secondary 

 consideration, and all the species above-mentioned— 

 although, some of them hail from tropical climes — 

 are accommodating enough with regard to tempera- 

 ture, with the exception, perhaps, of R. asplenioides 

 and H. hirsutum, which do better under warm-house 

 treatment. None should be watered overhead, as 

 the fronds discolour when such a course is followed, 

 but luxuriate and retain their beautiful colour for 

 three or four years when each is almost always 

 laden with the condensed moisture of the atmosphere 

 in which they grow. Draughts of dry air should be 

 rigorously guarded against, as a 

 few minutes' exposure to such 

 conditions would probably prove 

 fatal to the wonderfully delicate 

 pellucid fronds. Not a few species 

 require no artificial heat what- 

 ever, and the number of these 

 would probably be increased were 

 experiments conducted to prove 

 their hardiness. 



Some of the finest specimens of 

 filmy ferns in existence (in culti- 

 vation) are in the possession of a 

 leading London surgeon, and are 

 grown imder — at first sight — 

 unpromising conditions. Nothing, 

 however, can exceed the beauty 

 of these plants, which for some 

 years have had no artificial heat 

 whatever. The fronds are never 

 wetted overhead — although always 

 covered with condensed moisture 

 — and no air is ever given except 

 when watering is being per- 

 formed, and when other necessary work is being 

 attended to. During the hot summer days a spray 

 of water is kept plajong on the outside of the shaded 

 roof, and this, by keeping the iron- work and glass 

 cool, prevents the temperature from rising to any 

 great extent. 



Most of the Hymenophyllums succeed admirably 

 on fibrous tree-fern stems (such as those of Dicksonia) 

 — into which it is advisable to rub a little fine peat 

 before wiring on the slender rhizomes. Some do 

 thoroughly well on blocks of wood or on pieces of 

 sandstone. The British species do very well grown, 

 together with the small Mosses amongst which they 

 are found in a state of nature, against a wall of 

 peat, &c., to which they must be securely and firmly 

 fastened by wire-netting or some such contrivance. 

 Not a few of the species have been, and are now, 

 cultivated by a letter-carrier in one of our large 

 cities, without any properly-constructed case at all. 

 Barrels, &c., plimged in a piece of ground behind his 



dwelling, covered with sheets of glass, and of course 

 shaded from direct sunlight, fmnish quarters in 

 which splendid plants have been grown, specimens 

 which it would often be difficult to match in esta- 

 blishments where unlimited means are available. 

 Unlikely as it may appear, the finest fronds of 

 H. tunbridgense probably ever produced in England 

 are to be seen in the window-case of a dwelling- 

 house on the shady side of a crowded London 

 thoroughfare. The residence in question is that of 

 the surgeon above-mentioned, who has made filmy 

 ferns and their requirements a special study. The 

 same gentleman has H. demisstim 

 in magnificent condition under 

 precisely similar circumstances. 

 The window-cases used are to all 

 intents and purposes ordinary 

 ones, the only point in which they 

 differ from those in every-day use 

 being that they are double-glazed. 

 This double-glazing of course does 

 a great deal to maintain an equable 

 temperature, a most important 

 matter in connection with filmy 

 fern cultivation. A good 'many 

 of the species bear frost apparently 

 without any injury ; a number of 

 them withstood 14° of frost at 

 Messrs. J. Veitch and Sons', Chel- 

 sea, where for a whole fortnight 

 they were frozen into a solid block 

 of ice. When the thaw came they 

 were found in perfect health, much 

 better than plants of the same 

 species which had been kept in the 

 artificiaUy-heated temperature of 

 another house. AVhen watering, use a long-spouted 

 can, and take care not to wet the plants overhead ; the 

 condensed moisture in which they revel wiU be free 

 from the mineral constituents which often prove so 

 injurious to the membranous fronds. Now and then 

 the mycelium of various fungi appears amongst the 

 fibrous roots of the tree-fern stems ; this can as a 

 rule be got rid of by a careful dusting of flowers of 

 sulphur. Thrips are probably the insect pests which 

 prove the most troublesome ; but careful fumigating, 

 repeated several times if necessary, will be found 

 to extirpate them. If the cases, &c., in which the 

 plants are growing are placed inside a green-house, 

 fiU the latter with smoke and then remove the lids, 

 &c., of the filmy fern cases. Sometimes, in spite 

 of the densely moisture-laden atmosphere, the red 

 spider makes its appearance ; submerging the entire 

 plants for twelve or twenty-four hours in soft rain- 

 water will kill this insect, without injuring the 

 plants. Such treatment, however, proved ineffectual 



H. TUNBRIDGENSE. 



