Arachniodes Blume
Descripción
Rhizomes long- or short-creeping, rarely suberect (ours), scaly; fronds monomorphic, medium-sized, erect, not articulate; stipes with 3 or more vascular bundles in cross section, scaly throughout or only at bases; blades subcoriaceous, 2–4(–6)-pinnate, deltate to pentagonal, less often ovate, anadromous, proximal pinnae enlarged basiscopically, basiscopic edges of costular channels continuous with costal channels, with basiscopic edges continuous with rachis channels; rachises grooved adaxially, grooves narrow, continuous with those of costae, glabrous (ours) to hairy; segments often with acute or cuspidate teeth; veins free; indument absent or of minute hairs, glands and scales lacking; sori round; indusia round-reniform, each attached at a sinus, often caducous; paraphyses absent; spores bilateral with a winged or folded perispore; x=41.A
Forma de vida
o menos frecuente epipétrica o hemiepífita. TerrestreA
Distribución
México (país) Nativo y no endémicoA
Categoría IUCN
No incluidaB
Categoría NOM-059-SEMARNAT-2010
No incluidaC
Discusión taxonómica
According to Tindale (1961), Arachniodes is a genus of about 50 species, mostly of Southeast Asia, a few in Africa, and only four in the New World. Our species is the only widespread one in the Neotropics. The relationships of Arachniodes seem to be generally with Dryopteris and Polystichum, but perhaps more closely with Polystichopsis (primarily Antilles) or Cyclodium (primarily northern South America and Amazonia). Morton (1960) allied it with Ctenitis, but that differs in lacking pronounced rachis grooves and having minute septate hairs along the midribs adaxially. Tryon and Tryon (1982) included Arachniodes (and also Polystichopsis) in a broadly circumscribed Dryopteris. It is uncertain whether the neotropical species of Arachniodes are really congeneric with Old World species. Preliminary molecular data support inclusion of Arachniodes in the dryopteroid clade, but distinct from Dryopteris; however, sampling is insufficent to be more specific (Cranfill, unpubl. data). A