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NZ Plants

Adiantum diaphanum - small maidenhair fern, tuberous maidenhair fern

Family: Pteridaceae

Adiantum diaphanum is a terrestrial fern with short creeping stems (rhizomes) that form small tubers. The frond stalk (stipe) and axis (rachis) are hairless and bear dark green oblong leaflets.
Found on the Kermadec Islands and the North and South Islands in coastal and lowland forest.

Vegetative characteristics

Fertile frond and sporangia

Plant form: creeping stems with fronds up to 20 cm in length

Frond appearance: similar to sterile frond

Frond stalk, midrib: hairless

Sporangium location: on lower frond surface

Frond shape: triangular

Sporangium position: in shallow notch beneath reflexed leaflet margin

Frond blade: 1-2-pinnate (divided 1-2x into leaflets or pinnae)

Sporangia distribution: in groups (sori)

Frond surface: hairs  

Sorus shape: circular

Leaflets: oblong, curved downward at tip; irregularly lobed outer margins;  stalk attached at one end

Sorus covering: kidney-shaped marginal flap with hairs