This member of the Blechnaceae family was given this name by Georg Heinrich Mettenius in 1856. It is found in southern Argentina, south and central Chile and on the Falkland islands, growing in a rich but well drained soil with quite some water and lots of sun. The stem can grow to 35 centimetres in diameter, the entire plant to 170 centimetres in height. The spores are brown.
The genera name comes from the Greek word βλῆχνον, which means 'for a fern'. The species is named after the Straits of Magellan, along which sides it is found. The stem of a large plant by Mark Morgan.

