SCHIZAEACEAE

family of the fern order Filicales, class Filicopsida. It contains six genera and about 160 species and is called the climbing fern family. The family is considered to be relatively primitive because of the characteristic large, individually produced spore-bearing structures (sporangia) with a ring of thickened cells (annulus) around the apex; the sporangia are usually borne on special leaflets (pinnae) and lack a covering membrane (indusium). The ferns' underground, usually highly branched rhizomes either form clumps or are creeping. The genera are usually found in tropical and subtropical regions. The curly grass fern (Schizaea pusilla, one of about 30 species in the genus Schizaea) is a small plant with leaves of two kinds, grasslike and lobed. The climbing fern genus (Lygodium), represented by the North American climbing fern, or Hartford fern (L. palmatum), contains about 40 species that produce vinelike leaves in rows on the upper surface of a creeping stem. Anemia, with 90 species, is distinguished by its basal pair of pinnae, which are branched and bear sporangia but lack a green photosynthetic blade. In Actinostachys, the ray ferns, the blades are reduced to a very narrow strip on either side of the midrib.