Monographs Details: Adiantum
Authority: Mickel, John T. & Beitel, Joseph M. 1988. Pteridophyte Flora of Oaxaca, Mexico. Mem. New York Bot. Gard. 46: 1-580.
Description:Genus Description - Terrestrial or epipetric; rhizome short- to long-creeping or suberect, scaly; fronds small to large; stipe castaneous to atropurpureous, lustrous, glabrous to densely covered with narrow scales or hairs, brittle; blade simple to 5 times pinnate; segments often rhomboidal or trapezoidal or flabellate, sessile to short-petiolulate, but never adnate, often deciduous (articulate); lamina generally glabrous, sometimes glaucous, a few species with stiff hairs on the lamina; veins free, often dimidiate, rarely anastomosing, often with linear epidermal idioblasts; sporangia on the veins of recurved, membranous margin, sori short to linear or lunate, one to several per segment; paraphyses lacking; spores tetrahedral-globose.
Discussion:Lectotype (chosen by J. Smith, Hist. fil. 274. 1875): Adiantum capillus-veneris Linnaeus.
Hewardia J. Smith, J. Bot. (Hooker) 3: 432, t. 16, 17. 1841. Type: Hewardia adiantoides J. Smith [=Adiantum adiantoides (J. Smith) Christensen].
There are about 200 species, mostly of tropical America, a few reaching temperate regions. About 31 species occur in Mexico, and 25 in Oaxaca, of which 16 are widespread to South America and the West Indies. The species mostly grow in low to middle elevations in wet forests; one (A. capillus-veneris) is pantropical and subtropical of dry, limestone regions, and Adiantum andicola and A. poiretii are of high elevations.
References: Scamman, E. 1960. The maidenhair ferns (Adiantum) of Costa Rica. Contr. Gray Herb. 187: 322; Tryon, R. 1964. Adiantum. In The ferns of Peru. Contr. Gray Herb. 194: 135-180.