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NZ Plants

Hymenophyllum lyallii

Filmy fern family: Hymenophyllaceae

Hymenophyllum lyallii is a small pale green epiphytic filmy fern with long-creeping stems (rhizomes) bearing distinctive fan-shaped fronds with marginal forked hairs and deeply recessed sori.
A species found on tree trunks throughout New Zealand.

Vegetative characteristics

Fertile frond and sporangia

Plant form: creeping rhizome with fan-shaped fronds up to 4 x 3 cm

Frond appearance: similar to sterile frond

Frond stalk, midrib: stalk with forked hairs; midrib repeatedly forking

Sporangium location: on terminal ends of leaflets

Frond shape: fan-shaped

Sporangium position: leaflet margin

Frond blade: 1-3-pinnate (divided 1-3 times into leaflets or pinnae)

Sporangia distribution: in groups (sori)

Frond surface: filmy, translucent

Sorus shape: rounded

Leaflets: oblong, marginal forked hairs

Sorus covering: indusium widely gaping with forked hairs