Cyclosorus Link
Descripción
Rhizomes creeping to erect; fronds pinnate-pinnatifid, the proximal pinnae reduced or not (most American spp.); blades lacking aerophores or with only a small darkened protuberance where aerophores would be located, proliferous buds absent; lowermost veins of segments meeting margins at the sinuses or connivent just below the sinuses or meeting below the sinuses with an excurrent vein to the sinuses; indument abaxially of unbranched, unicellular, acicular hairs and sometimes capitate glands on the costae and veins; sori round, with usually large, persistent, hairy indusia; sporangia with or without hairs or glands from sporangial stalks; spores bilateral, dark, with an often broadly winged perispore; x=36.A
Forma de vida
TerrestreA
Categoría IUCN
No incluidaB
Categoría NOM-059-SEMARNAT-2010
No incluidaC
Discusión taxonómica
Subgenus Cyclosorus differs from other Mexican subgenera by the combination of the lowermost veins from adjacent segments running to the sinuses or uniting below the sinuses, absence of stellate hairs, pinnate-pinnatifid blades, round sori with relatively large, persistent indusia, and glabrous sporangia. Several species are among the most common and “weediest” Thelypteris in Mexico, and may occupy somewhat exposed sites on roadbanks, in ditches, and along paths.
Hybridization appears to be common in subgenus Cyclosorus when species co-occur (Smith, 1971, 1981; Smith in Mickel & Beitel, 1988). The most common hybrids in Mexico involve T. puberula, which see for discussion. Other species, e.g., T. albicaulis and T. ovata are probably also involved. Without a thorough field study of suspected hybridizing populations, it is not usually possible to determine the exact parentage of a given hybrid, but, because of the production of malformed spores, it is often possible to detect hybrids among herbarium specimens. Chromosomal studies are also needed to provide more conclusive evidence of parentage.
Holttum (1971) restricted the application of Cyclosorus to the type species and one other from Africa. Later, Holttum (1974) concluded that the American species previously ascribed to Cyclosorus by Christensen and others had closest affinities to Christella, a primarily Old World genus of about 60 species. For reasons discussed elsewhere (Smith, 1981, 1983), we prefer to recognize a more broadly circumscribed Cyclosorus, at the rank of subgenus, in the NewWorld comprising 18 species distributed from southeastern and southwestern United States, through Mexico, to northern Argentina and the Antilles. The greatest diversity is found in southern Mexico and it is here where species delimitations are most difficult.
Unplaced Name
Aspidium conspersoides Fée, Mém. Foug. 8: 105. 1857. Syntypes. Mexico. [Veracruz:] Orizaba, Schaffner 335, 463; Hispaniola. de Tussac s.n. (not found).
A
Hybridization appears to be common in subgenus Cyclosorus when species co-occur (Smith, 1971, 1981; Smith in Mickel & Beitel, 1988). The most common hybrids in Mexico involve T. puberula, which see for discussion. Other species, e.g., T. albicaulis and T. ovata are probably also involved. Without a thorough field study of suspected hybridizing populations, it is not usually possible to determine the exact parentage of a given hybrid, but, because of the production of malformed spores, it is often possible to detect hybrids among herbarium specimens. Chromosomal studies are also needed to provide more conclusive evidence of parentage.
Holttum (1971) restricted the application of Cyclosorus to the type species and one other from Africa. Later, Holttum (1974) concluded that the American species previously ascribed to Cyclosorus by Christensen and others had closest affinities to Christella, a primarily Old World genus of about 60 species. For reasons discussed elsewhere (Smith, 1981, 1983), we prefer to recognize a more broadly circumscribed Cyclosorus, at the rank of subgenus, in the NewWorld comprising 18 species distributed from southeastern and southwestern United States, through Mexico, to northern Argentina and the Antilles. The greatest diversity is found in southern Mexico and it is here where species delimitations are most difficult.
Unplaced Name
Aspidium conspersoides Fée, Mém. Foug. 8: 105. 1857. Syntypes. Mexico. [Veracruz:] Orizaba, Schaffner 335, 463; Hispaniola. de Tussac s.n. (not found).
A