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Wilsons Filmy Fern



Hymenophyllum unilaterale

The Wilson's Filmy Fern is regarded as a distinct species by some writers, although it differs so slightly from Hymenophyllum tunbridgense that we can hardly consider it as such, and it requires a practised observer to make the distinction insisted on by botanists. It is found in the same districts, and often accompanies it. Perhaps, however, the variety is the more common in Scotland and in Ireland than the original fern. The principal characters of distinction are found in the fructification. The cups or seed-vessels are larger, the valves more rounded, meeting by their edges, not compressed toward the apex, and never serrated. The darker green hue and coarser texture of the plant will generally enable the collector to distinguish this variety. The pinnae also are turned back in a direction contrary to the fructification.

Mr. Newman gives ample directions for the cultivation of this fern and the preceding species, and suggests that it be grown on the surface of an inverted flower-pot, well covered with a composition of silver sand, peat earth, and loam, resembling mortar, the flower-pot being first filled with wet sphagnum, and mounted into a saucer, likewise filled with sphagnum. The luxuriant growth of the fern is almost certain in this way. Both these ferns are very suitable for closed cases, and do well in them; but we are advised by those who have tried the experiment, to have two small apertures near the top of the glass shade, so as to prevent any retention of stagnant moisture. Mr. Clowes, whose culture of these ferns has been very successful, says that he has observed that the fronds of Hymenophyllum Tunbridgense are strictly annual, never growing for more than one year, while those of Hymenophyllum Wilsoni go on growing year after year.