Gleichenella Ching
Descripción
Rhizomes long-creeping, cord-like, solenostelic, bearing dense pluricellular, unbranched hairs; fronds monomorphic, erect or scandent, to several meters long; blades pseudodichotomous, with pinnae consistently and repeatedly unequally branching, i.e., the larger branch alternately to one side of the rachis and then the other, the minor branches also unequally branched, lacking basiscopic accessory branches at the forks; dormant buds covered by pluricellular hairs, also often with a pair of foliaceous, stipule-like outgrowths, at least within the proximal forks; penultimate divisions pectinate, bearing narrowly lanceate to linear segments; indument absent abaxially, or of sparse stellate hairs mainly on the axes; veinlets free, 2–4-forked; sori abaxial with (6–)8–16(–25) pear-shaped sporangia; paraphyses absent; sporangia with oblique annuli; indusia absent; spores bilateral, ellipsoid, with surface rugulate and of fine rodlets; x=43.A
Forma de vida
TerrestreA
Distribución
México (país) Nativo y no endémicoA
Categoría IUCN
No incluidaB
Categoría NOM-059-SEMARNAT-2010
No incluidaC
Discusión taxonómica
Most authors include Gleichenella in Dicranopteris, as subg. Acropterygium. As Østergaard Andersen and Øllgaard (2001) pointed out, differences in branching pattern, stele type, chromosome number, and spore morphology make Dicranopteris and Gleichenella at least as distinctive as the other recognized genera (Gleichenia s.str., Sticherus, Diplopterygium, and Stromatopteris) in the family. An alternative classification is to combine all genera in the family (excepting Stromatopteris) into a single genus Gleichenia, a solution not generally adopted even in conservative accounts of the family.
Gleichenella is monotypic, the range that of the single species. Affinities of Gleichenella and the family Gleicheniaceae have been shown in recent molecular analyses to be with the basal leptosporangiate ferns, arising above Osmunda in phylogenetic trees, but below the schizaeoid ferns and tree ferns (Hasebe et al., 1995; Pryer et al., 1995, 2001). The fossil history of the family dates back at least as far as the Jurassic (Gandolfo et al., 1997).
A
Gleichenella is monotypic, the range that of the single species. Affinities of Gleichenella and the family Gleicheniaceae have been shown in recent molecular analyses to be with the basal leptosporangiate ferns, arising above Osmunda in phylogenetic trees, but below the schizaeoid ferns and tree ferns (Hasebe et al., 1995; Pryer et al., 1995, 2001). The fossil history of the family dates back at least as far as the Jurassic (Gandolfo et al., 1997).
A