Blechnum penna-marina (Poiret) Kuhn

Little hard fern, dwarf hard fern, alpine water fern

Etymology The name means Sea pen. Most Sea pens bear little resemblance to any fern, but this one does.
Description Rhizome: short-creeping, branching.
Frond: 20 cm high by 2 cm wide, evergreen sterile fronds, dimorphic, fertile leaves appearing later, more erect than sterile, blade/stipe ratio: 3:1 in the sterile fronds but the stipe is longer in fertile fronds.
Stipe: reddish brown at base, becoming straw-colored upwards, scales bullate, linear to ovate, reddish-brown, vascular bundles: at least 3 vascular bundles arranged in arc.
Blade: 1-pinnate, linear-ovate, leathery, glossy, dark green in maturity, young fronds are often red, blade glabrous, rachis, costa, a few scales below.
Pinnae: 12 to 25 pair, to 1 cm, fertile very narrow, 2 mm, curving upwards, sterile narrow, 5 mm, basal pinnae shorter, rounder; costae rachis and costae straw-colored, scales on lower surface small, sparse, brown; margins entire; veins sterile:free, often forked; fertile: veins of fertile leaves united to form sorus-bearing secondary vein parallel to costa or costule.
Sori: elongate, continuous, on both sides of the costae, indusium: flap-like, opening towards the costa.
Culture Habitat: moist, acidic, alpine grasslands. Distribution: Argentina, Chile, New Zealand, southeastern Australia. Hardy to -25C, USDA Zone 5.
Synonyms
Polypodium penna-marina Poir.
Lomaria antarctica Carm.
newly emerged fronds
Blechnum penna-marina. Patagonia  Photo: John and Hilary Birks
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