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NZ Plants


Blechnum penna-marina, subsp.alpina - alpine hard fern

Hard fern family: Blechnaceae

Blechnum penna-marina subspecies alpina is a small fern with a creeping stem (rhizome) bearing a horizontal circle of bronze-green sterile leaves and erect fertile leaves up to twice as long as sterile .
Found in coastal and lowland forest throughout New Zealand.
 

Vegetative characteristics

Fertile frond and sporangia

Plant form: horizontal fronds up to 120 mm in length.

Frond appearance:  erect up to 250 mm, leaflets very narrow, mostly equal in length and widely spaced

Frond stalk, midrib: scales mostly at base of stipe, sparse elsewhere;  linear to ovate, red-brown

Sporangium location: on lower frond surface

Frond shape:  linear

Sporangium position: leaflet margin

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

Sporangium distribution: in groups (sori)

Frond surface: leathery

Sorus shape: in a continuous line either side of midrib

Leaflets: oblong, blunt or pointed, attached along broad base (adnate)

Sorus covering: linear covering (indusium) opening toward midrib