Blechnum

Blechnum, known as hard fern, is a genus of ferns in the family Blechnaceae, subfamily Blechnoideae, according to the Pteridophyte Phylogeny Group classification of 2016 (PPG I).[1] Two very different circumscriptions of the genus are used by different authors. In the PPG I system, based on Gasper et al. (2016),[2] Blechnum is one of 18 genera in the subfamily Blechnoideae, and has about 30 species.[1] Other sources use a very broadly defined Blechnum s.l., including accepting only two other genera in the subfamily. The genus then has about 250 species.[3] In the PPG I circumscription, the genus is mostly neotropical, with a few southern African species.

Blechnum
Blechnum occidentale in cultivation at Lotusland, Montecito, California
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Class: Polypodiopsida
Order: Polypodiales
Suborder: Aspleniineae
Family: Blechnaceae
Subfamily: Blechnoideae
Genus: Blechnum
L.
Type species
Blechnum occidentale
Species

See text.

Description

Plants in the genus Blechnum (as circumscribed in the PPG I classification) are mainly terrestrial or grow on rocks; few are epiphytes. Their rhizomes may be upright or creeping and have scales with entire margins or at most a few very small teeth. They generally form stolons, which is a characteristic of the genus. The sterile and fertile fronds are usually of the same form or at most slightly different. The blades of the fronds are of one colour and are usually pinnatisect or unipinnate, rarely entire. The leaf veins are usually free, dividing one to three times, each ending near the frond margin in an enlarged tip. The sori have indusia (scale-like coverings).[2]

Species
See also: List of transferred Blechnum species

Using the PPG I circumscription, as of December 2019, the Checklist of Ferns and Lycophytes of the World accepted the following species and hybrids.[4]

  • Blechnum anthracinum R.C.Moran
  • Blechnum appendiculatum Willd.
  • Blechnum arcuatum J.Rémy ex Fée
  • Blechnum areolatum V.A.O.Dittrich & Salino
  • Blechnum asplenioides Sw.
  • Blechnum auriculatum Cav.
  • Blechnum australe L.
  • Blechnum austrobrasilianum de la Sota
  • Blechnum × caudatum Cav.
  • Blechnum × confluens Schltdl. & Cham.
  • Blechnum × falciculatum C.Presl
  • Blechnum gracile Kaulf.
  • Blechnum gracilipes (Rosenst.) M.Kessler & A.R.Sm.
  • Blechnum guayanense A.Rojas
  • Blechnum hastatum Kaulf.
  • Blechnum heringeri Brade
  • Blechnum laevigatum Cav.
  • Blechnum lanceola Sw.
  • Blechnum × leopoldense (Dutra) V.A.O.Dittrich & Salino
  • Blechnum longipilosum V.A.O.Dittrich & Salino
  • Blechnum ludificans Herter
  • Blechnum malacothrix Maxon & Morton
  • Blechnum meridense Klotzsch
  • Blechnum occidentale L.
  • Blechnum × pampasicum de la Sota & M.L.Durán
  • Blechnum polypodioides Raddi
  • Blechnum punctulatum Sw.
  • Blechnum tomentosum M.Kessler & A.R.Sm.

References
  1. PPG I (2016), "A community-derived classification for extant lycophytes and ferns", Journal of Systematics and Evolution, 54 (6): 563–603, doi:10.1111/jse.12229, S2CID 39980610
  2. Gasper, André Luís De; Dittrich, Vinícius Antonio De Oliveira; Smith, Alan Reid & Salino, Alexandre (2016-09-21), "A classification for Blechnaceae (Polypodiales: Polypodiopsida): New genera, resurrected names, and combinations", Phytotaxa, 275 (3): 191–227, doi:10.11646/phytotaxa.275.3.1, ISSN 1179-3163, retrieved 2019-12-22
  3. Christenhusz, Maarten J.M. & Chase, Mark W. (2014), "Trends and concepts in fern classification", Annals of Botany, 113 (9): 571–594, doi:10.1093/aob/mct299, PMC 3936591, PMID 24532607
  4. Hassler, Michael & Schmitt, Bernd (November 2019), "Blechnum", Checklist of Ferns and Lycophytes of the World, 8.11, retrieved 2019-12-22

Further reading
  • Huxley, A., ed. (1992). New RHS Dictionary of Gardening. Macmillan
  • Moore, D. M. (1983). Flora of Tierra del Fuego
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