To embrace all the classes it is necessary not to neglect the above, although even if of interest to the florist they cannot be any source of profit. Yet they are considered the gems of the whole family of ferns. There are only three genera: hymenophyllum, tricho-manes and todea. To these may almost be added the Nephrolepis Piersoni and elegantissima. These three genera have numerous representatives in many parts of the world. The same difficulty would be met with in their cultivation here occurs with Odontoglossum crispum among orchids: our hot, dry summers and the necessity of fire heat in winter. To this class belongs the world famous Killarney fern, which grew, and if vandals have not destroyed it, yet grows among the shady nooks and rocks about the Lakes of Killarney. What a pity travelers do not search for a section of the vertebra of some extinct saint, of which that island has been so prolific, and leave the gem Trichomanes radicans in peace.
Some forty-five years ago, in fact, exactly that, the writer had charge of a cool conservatory. In that house on the south side of the north path, about halfway between the east and the west paths, and partly shaded by the fine heads of a Dicksonia antarctica and a Cyathea dealbata, one on either side, was a small case, perhaps about five feet long and two feet wide, with a hinged glass roof; and in this case some eighteen inches below the glass were several clumps of the Killarney fern (Trichomanes radicans) and the other British filmy fern, Hymenophyllum Tunbridgense. I have been particular in locating this little greenhouse within a greenhouse because I can see the Killarney fern now, although I have not seen one since it was my duty to lift up the lid and let in a little air if there was too great a degree of moisture on the delicate fronds. There was an older and wiser mind than mine who inspected these plants daily, and when I now read today of the most approved methods of culture of these wonderful ferns I can see that the house of forty years ago and their treatment was about right.
Pteris Tremula Smithae.
They are now seldom grown, but an ardent lover of ferns would surely like to have them under his care. Briefly then, the principal fact to realize is that wherever found their surroundings are charged with moisture: Light they have, but never the direct rays of the sun. Most of them have surface rhizomes and they need little soil, which can be broken up peat, chopped sphagnum and pounded up bricks or broken crocks. Moisture at the roots they want at all times and an atmosphere charged with moisture, but no syringing overhead. A dry, cutting draught, even in the greenhouse, would soon destroy them. The British species will withstand a temperature far below freezing, and the species from India and the West Indies, as well as those from China, Tasmania and New Zealand, are found at high elevations. The hymenophyllums " forming a green matting over constantly wet rocks."
A low temperature, shade and moisture are the essentials to success with these beautiful ferns, which the commercial florist will let severely alone.