Monographs Details: Cystopteris
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 slender, compact to long-creeping, scaly; fronds small to mediumsized, monomorphic, not articulate, erect to spreading; stipe slender, brittle, sparsely scaly to gla-brescent; blade pinnate-pinnatifid to tripinnate-pinnatifid; lamina thin, glabrous; veins free; sori abaxial, roundish, indusium hoodlike, attached on the basiscopic side and overarching the sorus, often shriveling or deciduous; paraphyses lacking; spores bilateral, dark.
Discussion:Type: Cystopteris fragilis (Linnaeus) Bernhardi [=Polypodium fragile Linnaeus].
Cystopteris is a temperate genus of about ten species; C. fragilis is cosmopolitan, perhaps the most widespread or most abundant of fern species in the world. Most species of Cystopteris are boreal, but C. fragilis occurs at high elevations in tropical regions. There are two species in Mexico, both in Oaxaca. Relationships of the genus are probably with Woodsia. Cystopteris is distinct by the hoodlike indusium.
References: Blasdell, R. F. 1963. A monographic study of the fern genus Cystopteris. Mem. Torrey Bot. Club 21(4): 1-102; Pearman, R. W. 1976. A scanning electron microscopic investigation of the spores of the genus Cystopteris. Brit. Fern Gaz. 11: 221-230.