Hymenophyllum rarum (Narrow filmy fern)
Species: H. rarum
Binomial name: Hymenophyllum rarum
Synonyms: Mecodium rarum, Hymenophyllum imbricatum, Hymenophyllum semibivalve, Trichomanes rarum, Hymenophyllum darwinii.
Common name: Narrow filmy fern.
Hymenophyllum rarum is a thin leaved fern found in New Zealand and Tasmania. It grows in patches on rocks and is often epiphytic on trees or tree ferns in rainforest or moist gullies.
It has a rhizome that is long, skinny, black. sparsely covered with red-brown hairs and is much-branched with spaced fronds. The fronds are pendent, to 15 cm long; stipe to 5 cm long, black; rachis winged in upper half of the frond; lamina 1-pinnate 1–2-pinnatifid, pale green, to 10 cm long and 1–2.5 cm wide, margins not toothed. The entire plant is glabrous (devoid of hairs or down).
The sori are solitary and are carried by the end of a segment, mainly to the terminal portion of the blade.
The indusium, a thin membrane completely covers the sporangia. The indusium splits apart when spores are ready to be dispersed.
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