Austroblechnum is a genus of ferns in the family Blechnaceae (order Polypodiales), placed within the subfamily Blechnoideae under the Pteridophyte Phylogeny Group's 2016 classification (PPG I). The genus was segregated from the broadly circumscribed Blechnum by Gasper & V.A.O.Dittrich in 2016 and encompasses roughly 34 species and two hybrids according to the Checklist of Ferns and Lycophytes of the World. Its classification remains debated: while PPG I treats Austroblechnum as a distinct genus, some authorities prefer to sink it back into a broadly defined Blechnum that spans the entire subfamily.
Members of Austroblechnum are terrestrial or rock-dwelling ferns, with a distribution centred on the Southern Hemisphere — particularly New Zealand, Australia, and South America. The genus includes the very widespread Austroblechnum penna-marina (alpine water fern), one of the most cold-tolerant ferns in the world, found from sea level to subalpine zones across New Zealand, southern Australia, and southern South America.
Distribution
Austroblechnum is primarily a Southern Hemisphere genus, with species distributed across New Zealand, Australia, and South America, and extending to equatorial regions (e.g., Austroblechnum aequatoriense). Several species, notably A. penna-marina, have exceptionally wide ranges spanning subantarctic and temperate zones.
Taxonomy Notes
Austroblechnum was segregated from Blechnum by Gasper & V.A.O.Dittrich in 2016 and accepted under the PPG I classification within subfamily Blechnoideae, family Blechnaceae. The genus is contested: some taxonomists prefer a broadly defined Blechnum encompassing the entire subfamily, which would render Austroblechnum synonymous with that genus.
