About Austroblechnum penna-marina (Poir.) Gasper & V.A.O.Dittrich
Austroblechnum penna-marina (Poir.) Gasper & V.A.O.Dittrich, with the synonym Blechnum penna-marina, has common names including Antarctic hard-fern, Little Hard Fern, Alpine Hard Fern, alpine water fern, and pinque (Chilean Spanish). It is a species of fern in the family Blechnaceae, widely distributed across the southern hemisphere. It has wiry rhizomes and shows strong frond dimorphism. Sterile fronds are prostrate or semi-erect, reaching up to 400 mm in length, while fertile fronds are longer and held upright. Sterile fronds have yellow-brown stems, and fertile fronds have purplish-black stipes. Both frond types have pinnatisect laminae with free veins. Sterile fronds bear 12–44 pairs of triangular or oblong pinnae, while fertile fronds have 10–36 pairs of linear to narrowly oblong pinnae, with tiny sterile flanges replacing pinnae at the base of fertile fronds. This fern grows in coastal to alpine environments, including open forests, grasslands, subalpine scrub, alpine herb fields, creek beds, river terraces, and rocky herb fields. It occurs from sea level up to 1900 meters above sea level, and its optimal temperature range for growth is 6 to 11 degrees Celsius. It is preyed on by endemic alpine grasshoppers including Brachaspis nivalis, Paprides nitidus, and Sigaus australis. The species is native to Marion Island, a subantarctic island located halfway between Africa and Antarctica. Within New Zealand, it is found across the entire country, from the North Island and South Island to the Chatham, Stewart, Auckland, Campbell, and Antipodes Islands. In the North Island, it grows from lowland to alpine areas, ranging from Hamilton and East Cape to southern Wellington. In the South Island and Stewart Island, it also occurs from lowland to alpine regions, and has been recorded growing at elevations as high as 1900 meters above sea level in the Spenser Mountains, Nelson. Its broad geographic distribution across the southern hemisphere demonstrates its adaptability to diverse habitats and climates.
