About Hymenophyllum flabellatum Labill.
This filmy fern, Hymenophyllum flabellatum, is set apart by its thin, membranous fronds that are only one cell thick and grow in moist environments. Fronds are pale yellow-green, covered in yellow-brown hairs, and reach 5–25 cm in length. They are linear with entire margins, growing terminally on short lateral segments, with a single vein in each lateral segment. Numerous sori develop at the tips of lateral segments; the indusium is two-lipped and slightly wider than the segment. Fronds are usually spaced apart and often pendant, and stomata are completely absent. The lamina is 2-3 pinnate, shaped ovate to linear, and yellow-green. Pinnae are narrowly rhomboidal to fan-shaped, and sometimes have long terminal segments commonly called "tailed". The stipe is slender, not winged, and has a tuft of hairs at its base. The rachis bears scattered hairs and is winged toward its upper sections. The receptacle is short and enclosed. This species, commonly called the shiny filmy-fern, grows in rainforests, where it forms mats on rocks and tree trunks, and can even grow as curtain-like growths in well-lit caves. It is widely distributed across Tasmanian rainforests, and also occurs on Flinders Island, in New South Wales, Victoria, and some areas of northern Queensland. It is also widely distributed throughout New Zealand. Because Australian rainforests where this fern grows are mostly located close to coastal areas to meet their precipitation needs, the shiny filmy-fern does not generally occur in inland Tasmania or inland mainland Australia.
