Schizaeales
Region: cosmopolitan; northern hemisphere as late as the Mesozoic, but by the Quaternary, there was a clear shift to a southern hemisphere distribution.
Botany
Leaves: dimorphic, fertile and sterile fronds; lack well-defined sori. Sporangia: with a horizontal annulus that lies below and completely encircles the top of the sporangium.
Families
Well-distinguished from one another by numerous morphological characters
Schizaeaceae: 2 genera, Actinostachys, Schizae.
Anemiaceae: flowering ferns; 1 genus, Anemiaceae.
Lygodiaceae: climbing ferns; 1 genus, Lygodium; 40 species; vines.
Introduction
While the three clades of Schizaeales are all .
Schizaeaceae are generally small ferns with forking fronds and a distinctive, somewhat non-fern-like, appearance.
Anemiaceae look very fern-like and are typically terrestrial or epipetric.
Lygodiaceae, or climbing ferns, look very ferny but are highly distinctive in their growth habit: the rachis of the frond is long and flexible, with indeterminate growth, so that the fronds form climbing or trailing vines.
Taxonomy
Smith in 2006 placed Schizaeales in the leptosporangiate ferns, class Polypodiopsida, with 3 families, Anemiaceae, Lygodiaceae, and Schizaeaceae. Christenhusz in 2011 placed Schizaeales in subclass Polypodiidae, with the same three families. Christenhusz and Chase in 2014 placed all members of the Schizaeales in a more broadly defined Schizaeaceae, reducing the three existing families to subfamilies as Anemioideae, Lygodioideae, and Schizaeoideae, as has been done in the past. The PPG I classification in 2016 returned to the three-family definition of the order.