Oleandra Cav.
Descripción
Rhizomes slender, long-creeping or sometimes climbing or erect, dictyostelic, densely scaly, scales peltate, rhizomes bearing long stiff roots; fronds commonly monomorphic, articulate at prominent joint, leaving short stalks (phyllopodia), borne at wide intervals or in loose clusters; blades simple, entire, glabrous to pubescent, hairs often septate, midribs slightly to rather densely scaly; veins free, unbranched or forked near base, parallel, often fusing with cartilaginous margin; sori round, borne irregularly on veins, but mostly near midribs; indusia round-reniform to reniform, attached at deep sinuses; spores bilateral, perispore winged, coarsely ridged, and often spinulose between the ridges; x=41, 40?
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Forma de vida
TerrestreA
Forma de vida y crecimiento (notas)
Rupícola u ocasionalmente epífita.A
Distribución
México (país) Nativo y no endémicoA
Categoría IUCN
No incluidaB
Categoría NOM-059-SEMARNAT-2010
No incluidaC
Discusión taxonómica
Oleandra is a pantropical genus with about eight species in the neotropics (Lellinger, unpubl.) and about 30 species in the Paleotropics from Africa to Polynesia; however, these numbers were considerably reduced by R. Tryon (1997, 2000), and reflect a much broader species concept. Oleandra is distinctive in its long-creeping, scandent to erect rhizomes, simple blades with stipes articulate above the rhizome (leaving short to often very long phyllopodia), and reniform indusia borne on parallel free veins. Its center of distribution in the neotropics is from Costa Rica to Colombia and Venezuela.
The affinities of Oleandra are uncertain, but probably with Arthropteris, a small genus occurring from Africa to Asia and Polynesia, extending to the Juan Fernandez Islands. Historically, Oleandra has been included with genera of the Davalliaceae (e.g., by Moran in Davidse et at., 1995). Others have included the genus in a broadly circumscribed Dryopteridaceae (e.g., A. F. Tryon & R. M. Tryon, 1982; Smith in Steyermark et al., 1995). Still others place it in its own family, Oleandraceae, along with one or two other small genera (e.g., Kramer in Kubitzki, 1990). Its coarsely ridged spores and base chromosome number clearly point to an alliance with the dryopteroid ferns sensu lato.
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The affinities of Oleandra are uncertain, but probably with Arthropteris, a small genus occurring from Africa to Asia and Polynesia, extending to the Juan Fernandez Islands. Historically, Oleandra has been included with genera of the Davalliaceae (e.g., by Moran in Davidse et at., 1995). Others have included the genus in a broadly circumscribed Dryopteridaceae (e.g., A. F. Tryon & R. M. Tryon, 1982; Smith in Steyermark et al., 1995). Still others place it in its own family, Oleandraceae, along with one or two other small genera (e.g., Kramer in Kubitzki, 1990). Its coarsely ridged spores and base chromosome number clearly point to an alliance with the dryopteroid ferns sensu lato.
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