Blechnum

Gasper, André Luís De, Dittrich, Viníciusantonio De Oliveira, Smith, Alan R. & Salino, Alexandre, 2016, A classification for Blechnaceae (Polypodiales: Polypodiopsida): New genera, resurrected names, and combinations, Phytotaxa 275 (3), pp. 191-227 : 205-206

Blechnum L., Sp. Pl. 2: 1077. 1753. — Type: Blechnum occidentale L., Sp. Pl. 2: 1077. 1753. Figs. 3D , 6A .

Distaxia C.Presl, Epimel. Bot. 110. 1851. — Type: Distaxia fraxinea (Willd.) C.Presl , based on Blechnum fraxineum Willd.

Mesothema C.Presl, Epimel. Bot. 111. 1851. — Blechnum sect. Mesothema (C.Presl) J.Sm., Hist. Fil. 301. 1875. — Type: Mesothema australe (L.) C.Presl, based on Blechnum australe L.

Plants terrestrial, epipetric, or rarely epiphytic; rhizomes erect to ascending, decumbent or short-creeping, stoloniferous, slender to rather stout, bearing linear or linear-oblong, pale or dark brown, concolorous or bicolorous, entire scales (or scales with few minute teeth); fronds monomorphic or subdimorphic; stipes slender, short (sometimes absent) or long, stramineous to pale brown or atropurpureus, with scales similar to those of rhizomes proximally, and sometimes with multicellular, catenate, hyaline hairs toward apices; blades concolorous, lanceolate to deltate-lanceolate, entire (rare), pinnatisect or 1-pinnate, gradually reduced or truncate proximally, apices pinnatifid or conform; rachises glabrous or pilose, without scales; buds absent; aerophores absent; pinnae sessile, adnate or subpetiolulate, lanceolate, oblong-lanceolate, ensiform, margins entire, finely denticulate; veins rarely partially anastomosing, usually free and then 1–3 furcate, each ending near margins in an enlarged tip; sori linear, continuous or rarely interrupted along the costae, indusia slightly erose or ciliate; x = 31.

Species number, comments, and distribution:— Ca. 25 species, mostly neotropical, a few in southern Africa. With the segregation of the other genera, Blechnum s.s. is characterized by stoloniferous rhizomes, monomorphic to subdimorphic fronds, and finely denticulate pinna margins. Blechnum is closely related to Austroblechnum , Cranfillia and Icarus (Gasper et al. in press).

Figures

FIGURE 3. General appearance of the genera of Blechnaceae subfamily Blechnoideae (A-D). A. Austroblechnum penna-marina (FURB06706); B. Blechnidium melanopus (P02439094); C. Blechnopsis orientalis (P01406555); D. Blechnum occidentale (FURB06701); E. Brainea insignis (P01482127); F. Cleistoblechnum eburneum (P00627565); G. Cranfillia fluviatilis (P01606472); H. Diploblechnum fraseri (P01557366); I. Doodia aspera (P01618184). Vouchers are indicated by herbarium barcodes.

FIGURE 6. Habitat of Blechnaceae genera. A. Blechnum occidentale; B. Brainea insignis; C. Cleistoblechnum eburneum. D. Cranfillia vulcanica; E. Diploblechnum fraserii; F. Doodia caudata; G. Icarus filiformis; H. Lomaria spannagelii; I. Lomaridium acutum. Photos from: A. Luis Adriano Funez; B. Ralf Knapp; C. Ralf Knap; D. Julie F. Barcelona; E. Michael Sundue; F. Paulo Araújo; G. WELT herbarium; H. Vinícius A.O. Dittrich; I. Tiago João Cadorin. Reproduced with permission from the authors.