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NZ Plants

Trichomanes venosum

Filmy fern family

Trichomanes venosum has long-creeping stems (rhizomes) with irregular narrow light-green translucent fronds. Leaflets are widely spaced along the frond axis (rachis) and each has a prominent vein that forks many times. Formerly known as Polyphlebium venosum.

A species found throughout New Zealand on wet coastal to mountain forest.


Vegetative characteristics

Fertile frond and sporangia

Plant form: creeping rhizome with fronds up to 14 cm

Frond appearance: similar to sterile frond

Frond stalk, midrib: stalk with no wings; midrib with wings above

Sporangium location: solitary at base of leaflet

Frond shape: elliptic to irregular

Sporangium position: sunk in blade of leaflet

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

Sporangia distribution: in groups (sori)

Frond surface: filmy, translucent

Sorus shape: circular with sporangia arranged in many tiers around central stalk (receptacle)

Leaflets: linear, smooth margin

Sorus covering: indusium tubular in shape