Psilotum Sw.
Descripción
Rhizomes short-creeping, much branched, with brown hairs; roots absent; aerial stems erect, arching to pendent, dichotomously branched several times, terete, angular or flattened, glabrous; true leaves absent but stems with minute, awl-shaped, scale-like enations; sporangia mostly 3-lobed, subtended by 2-lobed enations on distal branches; spores monomorphic, bilateral; gametophytes subterranean, fleshy, cylindrical; x=52.A
Forma de vida
Epífita, TerrestreA
Distribución
México (país) Nativo y no endémicoA
Categoría IUCN
No incluidaB
Categoría NOM-059-SEMARNAT-2010
No incluidaC
Discusión taxonómica
Psilotum is generally considered to have two pantropical species, growing mostly on the trunks of either living or fallen trees or at the bases of trees, but occasionally among rocks. Bierhorst (1977) proposed that Psilotum be considered a fern, and molecular evidence (Hasebe, M. et al., 1995; Pryer, K. M., et al. 2001) has shown that the family Psilotaceae is most closly allied to the Ophioglossaceae.A