Cyathea Sm.
Descripción
Stems erect, usually forming massive trunks to 20 m tall, 10 cm diam. (without the occasional mantle of wiry adventitious roots), scaly at apices; fronds large, to 4 m long; stipes stout, scaly, scales conform or marginate, concolorous to bicolorous, without dark apical setae, cells of the margins lightly to strongly different from those of the center in size, shape, and orientation; blades 2–3+-pinnate, chartaceous to coriaceous; axes with long, curved, acicular hairs adaxially, often with bullate scales abaxially, the rachises and costae rarely with spines; veins free, simple or forked; sori round, medial, with raised receptacles, indusia arising from beneath the sori and either completely enclosing them or forming cups or flat unequal-sided saucers, or absent; sporangia with slightly oblique annuli; spores tetrahedralglobose, 64 per sporangium; x=69.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
Cyathea is a genus of about 115 species, 8 in Mexico. The scaly tree ferns have been treated as a single genus (Holttum & Sen, 1962) and as six genera (R. Tryon, 1970). We are treating them here in four genera, following Lellinger (1987) and Moran (in Davidse et al., 1995).
Excluded Species.
Cyathea marginalis (Klotzsch) Domin, Pterid. Dominica 263. 1929. Alsophila marginalis Klotzsch, Linnaea 18: 542. 1844. Sphaeropteris marginalis (Klotzsch) R. M. Tryon, Contr. Gray Herb. 200: 20. 1970. Cyathea marginalis is represented by Jürgensen 915 (K), from Sierra San Pedro Nolasco, Oaxaca, but it is otherwise known only from the Guyana area. Tryon (Rhodora 74: 441–450. 1972) believed this to be an erroneous label. This number is cited by Fournier (1872) and Stolze (1974) as Cnemidaria decurrens.
A
Excluded Species.
Cyathea marginalis (Klotzsch) Domin, Pterid. Dominica 263. 1929. Alsophila marginalis Klotzsch, Linnaea 18: 542. 1844. Sphaeropteris marginalis (Klotzsch) R. M. Tryon, Contr. Gray Herb. 200: 20. 1970. Cyathea marginalis is represented by Jürgensen 915 (K), from Sierra San Pedro Nolasco, Oaxaca, but it is otherwise known only from the Guyana area. Tryon (Rhodora 74: 441–450. 1972) believed this to be an erroneous label. This number is cited by Fournier (1872) and Stolze (1974) as Cnemidaria decurrens.
A