A New Classification of Blechnum

Towards the end of 2016 several papers were published that in my view will have a profound effect on fern classification in general and the Hard Fern family in particular. Firstly the paper published by the Pteridophyte Phylogeny Group (PPG 1, A community-derived classification for extant Lycophytes and Ferns, Journal of Systematics and Evolution 54(6) 563-603) aims to produce a consensus classification for ferns and Lycophytes. 94 pteridologists have contributed to the project and the new classification should hopefully bring stability for some time. There are still genera that require further more detailed research and these are highlighted so this will not be the final word – not that there ever will be. This new classification does not spring any major surprises and in general summarises phylogenetic research over the last 20 years. The one family that does undergo a major re-organisation is the Blechnaceae. This due to the acceptance by the PPG of 2 papers published in late 2016. These are; Gasper et al, Molecular Phylogeny of the fern family Blechnaceae (Polypodiales) with a revised genus level treatment , Cladistics published online 19th October 2016 and Gasper et al, A classification for Blechnaceae (Polypodiales; Polypodiopsida); New genera, resurrected names and combinations, Phytotaxa 275(3) 191-227. The second of these papers publishes several new genera and resurrects some older genera as well as publishing many new species combinations within these genera.
Blechnum has previously been known to be morphologically very diverse and molecular studies have shown that most of the previously accepted genera are nested within Blechnum itself. There are 2 ways to deal with this problem, lumping or splitting. Recently it has been suggested that Blechnum should be enlarged and genera such as Doodia should be included. This option only delays the inevitable consequences that such well defined genera such as Sadleria should also be included in Blechnum. The new proposals split Blechnum into many smaller genera. Most of these are morphologically consistent and can be easily distinguished as groups of related species.

It will take some time for most of these changes to become generally accepted however I have recently noted that Bowdens Hostas have started to use some of the new generic names on their website so I think it is time to start raising awareness of this new classification.

Here is short list of some of the new and resurrected genera and how the names of some well known species will be affected. Note that Doodia, Brainea and Sadleria survive in this new classification. Many other genera and combinations can be found in the paper cited above.

Now a small genus that retains species such as B. occidentale, B. appendiculatum, B. australe and B. hastatum.

Our native Hard Fern (Blechnum spicant) becomes Struthiopteris spicant a name that was well known in the past.

B. penna-marina = Austroblechnum penna-marina. Unfortunately subsp. alpinum has yet to be combined in Austroblechnum but will hopefully be in the near future.
B. blechnoides = Austroblechnum banksii, a welcome return of the well-known specific epithet.
B. colensoi = A. colensoi
B. chambersii = A. lanceolatum
B. mochaenum = A. lechleri

B. cordatum = Parablechnum cordatum
B. novae-zelandiae = P. novae-zelandiae
B. montanum = P. montanum
B. capense = P. capense

B. brasiliense = Neoblechnum brasiliense

B. gibbum = Oceanopteris gibba
B. cartilagineum = O. cartilaginea

B. discolor = Lomaria discolor
B. nudum = L. nuda

B. tabulare = Lomariocycas tabularis
B. magellanicum = L. magellanica
B. cycadifolium = L. cycadifolia
B. palmiforme = L. palmiformis

B. fluviatile = Cranfillia fluviatilis
B. vulcanicum = C. vulcanica
B. longicauda = C. longicauda

B. orientale = Blechnopsis orientalis

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3 thoughts on “A New Classification of Blechnum”

  1. Hi Ashley
    Most of the genera are easily recognisable. There are a few exceptions in most of the genera.
    Cranfillia seems to be most varied as the 3 well-known species look very different from each other.

    I hope to prepare an article for The Pteridologist over the coming year that will go into more detail.

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