Monographs Details: Asplenium
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, epipetric, or epiphytic; rhizome short-creeping to erect, scaly, mostly with clathrate scales; fronds clumped, small to medium-sized, rarely large, erect, spreading, pendent or flat on ground or rocks; stipe green to atropurpureous or black, often slightly winged; blade simple to tripinnate, most often once-pinnate; lamina glabrous, some with scales on axes; veins free, stopping short of margin in clavate tip; sori abaxial, along the veins, oblong to linear, indusiate; indusium persistent, entire to erose; sporangia with slender, uniseriate stalk; spores bilateral, black, with distinct perispore.
Discussion:Lectotype (chosen by J. Smith, Hist. fil. 316. 1875): Asplenium marinum Linnaeus.
Asplenium is a cosmopolitan genus of about 700 species, mostly of the tropics, 55 in Oaxaca. It includes some of the most difficult taxonomic problems of the Oaxacan ferns. Hybridization is common among the temperate species of Asplenium, but the tropical species have not been studied sufficiently to see what part it plays in speciation there.
Three other genera of Oaxaca ferns, all rare and with undivided blades, are closely allied to Asplenium. Holodictyum can be distinguished by its net venation, and Phyllitis and Schaffneria by their paired sori facing each other from adjacent veins.
References: Maxon, W. R. 1913. Asplenium trichomanes and its American allies. Contr. U.S. Natl. Herb. 17: 134-153; Morton, C. V. & D. B. Lellinger. 1966. The Polypodiaceae subfamily Asplenioideae in Venezuela. Mem. New York Bot. Gard. 15: 1-49.