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NZ Plants

Hymenophyllum bivalve

Filmy fern family: Hymenophyllaceae

Hymenophyllum bivalve is a terrestrial or sometimes an epiphytic filmy fern, with long-creeping stems (rhizomes) bearing pale green hairless, triangular fronds. Frond margins are finely toothed and sori are held horizontally or slightly bent.
Found throughout New Zealand.

Vegetative characteristics

Fertile frond and sporangia

Plant form: creeping rhizome with fronds up to 20 cm

Frond appearance: similar to sterile frond

Frond stalk, midrib: stalk sparsely hairy; midrib narrowly winged

Sporangium location: on terminal ends of leaflets

Frond shape: ovate to triangular

Sporangium position: leaflet margin

Frond blade: 3-4-pinnate (divided 3-4 times into leaflets or pinnae)

Sporangia distribution: in groups (sori)

Frond surface: filmy, translucent

Sorus shape:

Leaflets: linear, shallowly-toothed margin

Sorus covering:  indusium flaps smooth-edged