Blechnum Linnaeus (1753: 1077) Type: Blechnum occidentale Linnaeus (1753: 1077) (as Blechnum orientale). Plants terrestrial or epipetric, rarely hemiepiphytes or epiphytes, very rarely aquatic; stem short to long creeping, decumbent, erect or even scandent, in some species forming a caudex to 3 m high, dictyostelic, stoloniferous or not, covered by basifixed scales, generally with long, fibrous roots; fronds monomorphic, subdimorphic or dimorphic (the fertile generally longer and narrower than the sterile), 8–250 cm long; stipe always present, not articulated to the rhizome, adaxially grooved; sterile blade generally pinnatisect, pinnate or pinnatifid, rarely simple, pinnate-pinnatifid or bipinnate, glabrous or covered with a few scales, rarely pubescent with glandular or non-glandular hairs, these unicellular or multicellular; rachis adaxially grooved, the grooves not continuous from rachis to costae, covered with scales or not, rarely with hairs (glandular or not); bulbils absent or rarely present at pinnae bases, adaxially; aerophores absent or present at pinnae bases abaxially, sometimes on the stipe; pinnae with margins entire to serrate, very rarely deeply incised, sometimes auriculate, continuous with the rachis or rarely articulate to it, adnate to rachis or not, sessile or petiolulate; veins generally free, simple or 1–2(3–4)-bifurcate, rarely partially anastomosing, without free included veinlets, in most species with enlarged endings, ending at the margin or near to it; sori on a long or rarely short vascular commissure, linear, parallel and close to the main vein of the segment, sometimes extending beyond the commissure (seemingly acrostichoid), without paraphyses, protected by a long, commonly narrow, introrse indusium, initially covering the sporangia, sometimes eventually fugacious or hidden by the sporangia, in species with strongly dimorphic fronds seemingly marginal; sporangia with a 3-rowed stalk; spores monolete, ellipsoidal to somewhat spheroidal, the laesura measuring ½ to ¾ of the spore length, the exine and perispore smooth to variously ornamented, without or very rarely with chlorophyll. Chromosome base number: x= 28, 29, 31, 32, 33, 34, 36. In the study area 11 taxa were recorded, nine of which are species and two are hybrids.

Published as part of Dittrich, Vinícius Antonio De Oliveira, Salino, Alexandre & Monteiro, Reinaldo, 2015, The Blechnum occidentale (Blechnaceae, Polypodiopsida) species group in southern and southeastern Brazil, pp. 201-229 in Phytotaxa 231 (3) on page 203, DOI: 10.11646/phytotaxa.231.3.1, http://zenodo.org/record/13630247