Blechnaceae

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Blechnaceae

Description

Occasionally scandent, terrestrial or epilithic, rarely epiphytic, small to large ferns.

Distribution

Antarctic:, Tristan da Cunha (Tristan da Cunhapresent) Asiatic-Australasiatic-Pacific: present Juan Fernandez: present Pacific:, Hawaiipresent nearly throughout the world: present northern hemisphere: present southern hemisphere extending to the mountains of the tropics: present
The family is distributed nearly throughout the world. Blechnum is by far the largest genus, with most representatives in the southern hemisphere extending to the mountains of the tropics and relatively few species in the northern hemisphere. Woodwardia is a counterpart of Blechnum and nearly confined to the northern hemisphere, where its distribution pattern is somewhat disjunct and possibly relict. Most of the other genera are Asiatic-Australasiatic-Pacific. Blechnaceae occur in a wide range of habitats, mostly terrestrial, but are rarely found in dry environments. They play an important part in the vegetation of some oceanic archipelagos like Tristan da Cunha, Juan Fernandez, and Hawaii.

Cytology

Blechnaceae are one of the cytologically most complex fern families. Probable or certain base numbers found so far are 32 (Doodia); 28-37 but most commonly 28 and 33 (Blechnum); 33 (Brainea, Sadleria); 34 and 35 (Woodwardia); and 74 (from 37?) (Strenochlaena). Tetraploids are frequent in Blechnum (Walker, 1966, 1973). Salpichlaena, with n = 40, is kept separate from Blechnum partly because of the divergent base number. Some authors tentatively regard x = 33 as the basic number in the family (Walker 1973).

A hybrid was reported in Doodia (Parris 1972). The variability of many species in the Blechnum occidentale complex is largely due to hybridization (see especially Walker 1973: f. 7).

Citation

K.U.Kramer, T.C.Chambers & Hennipman - in Kubitzki, Fam. Gen. Vasc. Pl., Pteridophytes and Gymnosperms. 1990: 60
C.Presl, Epimel. Bot. 1851: 103