Blechnaceae |
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Plants terrestrial or climbing (by means of rhizomes in Stenochlaena and Blechnum sect. Lomaria (Willd.) Diels, or by leaves in Salpichlaena), rarely epiphytic or rheophytic; roots blackish, wiry, inserted radially, non-proliferous; rhizomes short- to long-creeping, suberect, or erect, sometimes massive and arborescent (Blechnum sect. Lomariocycas (J. Sm.) C.V. Morton, and Sadleria), branched, or more commonly unbranched, sometimes stoloniferous (Blechnum sect. Eublechnum Hook. & Baker), bearing scales; rhizome scales lanceolate to linear-lanceolate, non-clathrate, light-brown to blackish, the margins glandular or not, entire or dentate, without distinct pubescence; leaves reddish when young, green at maturity, sometimes covered in mucilage when young (some Blechnum), monomorphic or dimorphic, spirally arranged, occasionally bulbiferous, the bulbils frequently in a distal pinna axil, leaves usually closely spaced, sparsely to densely scaly, sometimes pubescent, sometimes with glandular nectaries (e.g., Stenochlaena palustris (Burm. f.) Bedd., Blechnum orientale L.); petioles greenish to dark brown or atropurpureous, the bases not expanded, not articulate to the rhizome, usually not persistent; petiolar vasculature with two large bundles on the adaxial side of the petiole and an arc of smaller bundles on the abaxial side of the petiole, rarely petioles with only two bundles (e.g., Woodwardia areolata (L.) T. Moore), the larger bundles with hippocampiform-shaped xylem, distally uniting to form a single U-shaped bundle; laminae soft-herbaceous to more often coriaceous, pinnatifid to 2-pinnate-pinnatifid, the base with or without a series of reduced pinnae, the apex conform or not, the leaf marginal cells differentiated and scarious or membranaceous, or non-differentiated; pinna axes articulate (Stenochlaena), or usually non-articulate, pinna bases sometimes with conspicuous aerophores in Blechnum, the aerophores appearing as a low protuberance or elongate and vermiform (e.g., Blechnum violaceum (Fée) C. Chr.); rachis axes sulcate adaxially, rarely not (e.g., some Woodwardia), the sulcae not continuous onto the next order, lacking a free central ridge; veins anastomosing, or more commonly with costular areoles and otherwise free, the areoles without free included veinlets, reaching the leaf margin or terminating before it, the vein endings forming hydathodes, or not differentiated; sori elongate, along one side of the costular commissural vein, indusiate, or sori acrostichoid and exindusiate (Stenochlaena); soral receptacle flat; indusia lateral, essentially flat, glabrous or sometimes glandular, opening along the lateral margin with the opening facing the costa; sporangia with stalks more than one cell wide in the middle; spores monolete, occasionally chlorophyllous (e.g., Blechnum nudum (Labill.) Leurss.; Sundue & al., 2011), usually non-chlorophyllous, usually pale brown or tan, the perispore with sharp ridges, broad folds, echinulate, tuberculate, foliose, or nearly plain; chromosome base numbers x = 27 (Pteridoblechnum; Tindale & Roy, 2002), 29 (Blechnum; Walker, 1973a), 31 (Blechnum; Walker, 1973a), 32 (Doodia; Tindale & Roy, 2002), 33 (Blechnum, Sadleria; Walker, 1973a; Smith & Mickel, 1977; F.S. Wagner, 1995), 34 (Blechnum, Woodwardia; Manton & Sledge, 1954; Tryon & Tryon, 1982), 35 (Brainea, Woodwardia; Britton, 1964; W.H. Wagner, 1955; Aziz Bidin, 1995), 36 (Blechnum; Walker, 1973a), 37 (Stenochlaena; Manickam & Irudayaraj, 1988), or 40 (Salpichlaena; Walker, 1973b). The family Blechnaceae includes about 200 species in 9 genera. Blechnaceae are unique among ferns in having elongate sori along a sub-costular commissural vein that is parallel to the pinna costa, with an indusiate sorus that opens to face the costa. Other ferns with elongate sori lack a commissural vein, and have indusia that face the costa at a low angle (not parallel) or are exindusiate. Blechnaceae also differ from nearly all other Eupolypods II by having petioles with a vascular anatomy that resembles those of Eupolypods I. That is, in addition to the two large bundles on the adaxial side of the petiole, there is an arc of smaller bundles along the abaxial side of the petiole. However, Woodwardia areolata is aberrant among Blechnaceae in having only two. Rothfels C.J., M.A. Sundue, L-Y. Kuo, A. Larsson, M. Kato, E. Schuettpelz & K.M. Pryer. (2012) A revised family-level classification for eupolypod II ferns (Polypodiidae: Polypodiales) Taxon 61: 515-533. Smith A.R., K.M. Pryer E. Schuettpelz, P. Korall, H. Schneider & P.G. Wolf. (2006) A classification for extant ferns. Taxon 55: 705-731. Global distribution of Blechnaceae. CAUTION: GBIF records include introduced and cultivated plants. In addition, GBIF may follow a different taxonomic interpretation from that adopted in the treatments presented here. For all three reasons, the distribution shown may differ from statements presented here about a taxon's native distribution.
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