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NZ Plants

Hymenophyllum frankliniae - rusty filmy fern

Filmy fern family: Hymenophyllaceae

Hymenophyllum frankliniae is an epiphytic filmy fern with long, thin creeping stems (rhizomes) that form dense patches, usually on tree ferns, of olive-green fronds covered with stellate hairs. Formerly known as Hymenophyllum ferrugineum.

An endemic species found in lowland to montane forest throughout New Zealand.


Vegetative characteristics

Fertile frond and sporangia

Plant form: creeping rhizome with fronds up to 25 cm

Frond appearance: similar to sterile frond

Frond stalk, midrib: stalk wiry, hairless; midrib with narrow wing in upper portion

Sporangium location: on terminal ends of leaflets

Frond shape: narrowly elliptic to narrowly oval

Sporangium position: leaflet margin

Frond blade: 2-3-pinnate (divided 2-3 times into leaflets or pinnae)

Sporangia distribution: in groups (sori)

Frond surface: dense covering of stellate hairs

Sorus shape: rounded

Leaflets: oblong, smooth margin

Sorus covering: indusium flaps smooth-edged