Blechnum

Location & distribution maps

Phylogeny & links to associated information

Wikipedia links:       Monilophytes > Polypodiales > Blechnaceae > Blechnum

Other links:     https://www.researchgate.net/publication/350486671_Blechnaceae   

Species:     B cartilagineum   B neohollandicum   B nudum   B patersonii  B penna-marina   B wattsii

Plant  information

Common name:         Hard Fern  

Conservation status: ...

Etymology:   

• From Latin blachnon, a fern, from Greek blēchnon

Spores:                            

• The sori have indusia (scale-like coverings)

• Distinguished by sori that are either 

  • continuous

  • or elongate and discrete, arranged parallel to the costae (mid-rib), and indusia opening inwards towards the costae 

Leaves:         

• 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

• Distinguished by its often strongly dimorphic fronds

Stem & branches: 

• They generally form stolons (creeping horizontal stems)

Roots:         

• Their rhizomes may be upright or creeping

• Have scales

• Entire margins or at most a few very small teeth

Habit:        

• Blechnum (as circumscribed in the PPG I classification) are mainly terrestrial or grow on rocks

• Few are epiphytes

• Stolons are characteristic of this genus

Habitat:   

Distribution:                  

Species:                     

• World:            30 

• Australia:      . . .

Additional notes:     

• Taxonomy

  • Two very different circumscriptions of the genus are used by different authors

  • In the PPG I system, based on Gasper et al. (2016), Blechnum is one of 18 genera in the subfamily Blechnoideae, and has about 30 species

  • 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 (Australia: c 25 species, all States)

  • In the PPG I circumscription, the genus is mostly neotropical, with a few southern African species

• 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:

• Diversity & distribution (from NZ persective)

  • Blechnaceae is a medium-sized family found throughout the world, but with the majority of species in the southern hemisphere 

  • There are two main centres of diversity in Central and South America, and in Australasia and the south-west Pacific, with a smaller one in the Malesian region

  • Species occur most frequently in south temperate regions or in montane to subalpine areas of the tropics. As interpreted here, Blechnaceae is a family of seven genera and about 265 species, represented in New Zealand by a single genus, Blechnum, with 23 indigenous and two naturalised species

  • Thirteen species are endemic

• Alternative classifications

  • Alternative classifications recognise up to 25 genera, with seven indigenous to New Zealand (Austroblechnum, Cranfillia, Diploblechnum, Doodia, Icarus, Lomaria and Parablechnum) and two with introduced species (Austroblechnum, Blechnum). 

  • Under this classification Austroblechnum is represented by seven indigenous species, Doodia and Parablechnum by five, Cranfillia by three, and Diploblechnum, Icarus and Lomaria by one species each. Of the indigenous species, Blechnum chambersii, B. deltoides, B. fluviatile, B. membranaceum, B. minus, B. novae-zelandiae, B. penna-marina, B. procerum and B. triangularifolium are all widespread, albeit scarce or absent in the driest parts of the South Island. Blechnum colensoi, B. discolor and B. nigrum are widespread in the North Island but largely confined to wetter, western parts of the South Island. 

  • Blechnum banksii and B. durum are both entirely coastal, the former found predominantly on the west coast from Northland to Stewart Island and on the subantarctic islands, and the latter confined to the far south from Fiordland and Southland to the subantarctic islands. One species, B. montanum, has a predominantly southern distribution, occurring from Mt Pirongia in the North Island to the subantarctic. Three species, Blechnum filiforme, B. fraseri and B. parrisiae, have a mainly northern distribution extending only to the northern South Island, and another two, B. molle and B. zeelandicum, are confined to the North Island. The remaining species have restricted distributions: B. kermadecense occurs only on the Kermadec Islands, B. norfolkianum only on the Kermadec Islands, 

  • Three Kings Islands, and coastal regions of eastern Northland and Auckland, and B. neohollandicum is a vagrant species recorded from the northern North Island but is probably no longer extant in New Zealand. All species of Blechnum in New Zealand are terrestrial except for B. filiforme, which is one of the few high-climbing ferns in the flora. 

  • Hybrids are known to occur between B. chambersii and B. membranaceum, B. molle and B. parrisiae, and in the B. procerum group (including B. minus, B. montanum, B. novae-zelandiae and B. procerum).

Source:     https://www.researchgate.net/publication/350486671_Blechnaceae   

Sources of information:

• https://en.wikipedia.org/wiki/Blechnum (2023)

•  https://www.researchgate.net/publication/350486671_Blechnaceae    (2023)