Coenopteridales

(paleobotany) A heterogeneous group of fernlike fossil plants belonging to the Polypodiophyta.

True ferns which span the Late Devonian through Permian time between the recognizable beginnings of fernlike morphology and the earliest-appearing extant filicalean families (Gleicheniaceae, Osmundaceae). A true fern is a relatively advanced type of vascular land plant with distinct stem, fronds, roots, and foliar-borne annulate sporangia. Coenopterid ferns are mostly small and simple in contrast to late Paleozoic tree ferns of the Marattiales.

There are two major distinct groups. Zygopterid ferns are the most ancient and diverse, and apparently a dead-end evolutionary line; they differ the most from other ferns. Coenopterid ferns are usually placed in the Anachoropteridaceae and Botryopteridaceae, or in one of several extinct families assigned to the Filicales. Coenopterid ferns sensu stricto are probably ancestral to, and consequently form an imperceptible transition with, the Filicales.

The Zygopteridaceae appear in Late Devonian time, the Botryopteridaceae in Visean (Mississippian), the Anachoropteridaceae in the lower Westphalian A (Pennsylvanian), and all families extend into the Permian. See also Paleobotany.