Onocleaceae

Onocleaceae is a small family of terrestrial ferns in the order Polypodiales. It is placed in the suborder Aspleniineae in the Pteridophyte Phylogeny Group classification of 2016 (PPG I). Alternatively, the family, along with Blechnaceae, may be placed in a very broadly defined family Aspleniaceae as the subfamily Blechnoideae. The family may contain from one to four genera, consisting of five species largely in north temperate climes. The four genera, Matteuccia, Onoclea, Onocleopsis and Pentarhizidium, may be included under the single genus Onoclea.

==Description== Members of the family have the following characteristics, being distinguished by having strongly dimorphic fronds, with the fertile fronds different from the sterile fronds. The rhizomes are long- to short-creeping to ascending, and sometimes stoloniferous (Matteuccia and Onocleopsis). The leaves are strongly dimorphic and the petioles have two vascular bundles uniting distally into a gutter-shape. The blades are pinnatifid or pinnate-pinnatifid. The veins are free or anastomosing, lacking included veinlets. The spores are reniform, brownish to green. The sori are enclosed (sometimes tightly) by reflexed laminar margins, also with membranous, often fugacious true indusia.