Blechnum

Blechnum (hard fern) is a genus of between 150 and 220 species of ferns with a cosmopolitan distribution, in the family Blechnaceae in the eupolypods II clade of the order Polypodiales. By far the greatest species diversity is in tropical regions of the Southern Hemisphere, with only a few species reaching cool temperate latitudes in the Southern Hemisphere (notably B. penna-marina, south to Cape Horn, Chile, the southernmost fern in the world) and Northern Hemisphere (notably B. spicant, north to Iceland and northern Norway).

Most are herbaceous plants, but a few species (e.g. B. buchtienii and B. schomburgkii in Ecuador) are tree ferns with stems up to 3 m tall. Blechnum varies from most ferns in having a separation of sterile (photosynthetic) and fertile (reproductive) fronds in the same plant.


 * Selected species
 * Blechnum arcuatum
 * Blechnum ambiguum (C.Presl) Kaulf. ex C.Chr.
 * Blechnum blechnoides
 * Blechnum brasiliense Desv.
 * Blechnum buchtienii Rosenst.
 * Blechnum cartilagineum Sw.
 * Blechnum chambersii
 * Blechnum chilense Kaulf.
 * Blechnum cordatum (Desv.) Hieron. (syn. B. chilense)


 * Blechnum cycadifolium (Colla) Sturm.
 * Blechnum dendrophilum
 * Blechnum discolor
 * Blechnum durum
 * Blechnum eburneum
 * Blechnum filiforme
 * Blechnum fluviatile
 * Blechnum gibbum
 * Blechnum indicum Burm.f.
 * Blechnum lanceola Sw.
 * Blechnum magellanicum
 * Blechnum membranaceum (Col.) Mett.
 * Blechnum minus
 * Blechnum monomorphum
 * Blechnum nigrum
 * Blechnum nipponicum (Kunze) Makino
 * Blechnum novae-zelandiae T.C.Chambers & P.A.Farrant
 * Blechnum nudum (Labill.) Mett. ex Luerss.
 * Blechnum obtusatum (Labill.) Mett.
 * Blechnum occidentale L.
 * Blechnum orientale L.
 * Blechnum patersonii
 * Blechnum penna-marina (Poir.) Kuhn
 * Blechnum petiolare
 * Blechnum schomburgkii (Klotzsch) C.Chr.
 * Blechnum serrulatum Rich.
 * Blechnum spicant (L.) Sm.
 * Blechnum socialis
 * Blechnum tabulare
 * Blechnum vittatum Brack.
 * Blechnum volubile Kaulf.
 * Blechnum wattsii, Tindale Hard Water Fern

Circumscription
The circumscription of the genus has varied since it was established by Linnaeus in 1753. Some authors have put many of its species in a segregate genus Lomaria. DNA taxonomy indicates that the genus Doodia is embedded in Blechnum.

Cultivation and uses
Several species are grown as ornamental plants in gardens.