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NZ Plants

Tmesipteris lanceolata - fork fern

Family: Psilotaceae

Tmesipteris lanceolata is occasionally terrestrial but usually an epiphyte on tree fern trunks. It has a creeping stem (rhizome) that lacks roots, absorbing water instead with filamentous rhizoids. A pendulous and undivided aerial stem is formed that lacks true leaves, functioning instead with scale leaves. Scale leaves are flattened in one plane, are glossy green, broad, and stiff. Round-ended sporangia are fused in pairs and lie on the upper surface at the base of forked fertile leaves.
Found on the North Island south to the Bay of Plenty

Vegetative characteristics

Fertile scale leaf and sporangia

Plant form: pendulous unbranched stem, up to 20 cm long

Dstribution, appearance: mostly on the lower portion of stem; forked, same size as sterile leaves

Scale leaf arrangement: in two rows

Sporangium location: upper surface of fertile scale leaf

Scale leaf shape: oval, tapering to a short spine-like tip

Sporangium position: at base of fertile scale leaf

Scale leaf size: up to 25 mm  

Sporangia distribution: in a fused pair (synangium) of equal size, 2-4 mm long

Scale leaf surface: glossy green, leathery

Sporangium shape: with round ends