Species of the Athyriaceae are terrestrial or lithophytic, less commonly aquatic. They grow from various kinds of rhizome: short or long, creeping or erect, branched or not. The distribution and evolution of characters in the family is complex, and the genera have few constant features by which they can be identified. The sporangia have stalks two or three cells wide in the middle, and contain brown monolete spores.[2]
Taxonomy
Earlier classifications
The family was first created by Arthur H.G. Alston in 1956. It has had a varied history. In 2014, Christenhusz and Chase submerged it as the subfamily Athyrioideae within the family Aspleniaceae,[3] a status maintained by Plants of the World Online as of July 2019[update].[4] The PPG I classification of 2016 restored it to family status.[1]
Athyriaceae is a member of the eupolypods II clade (now the suborder Aspleniineae), in the order Polypodiales.[5] It is related to other families in the clade as in the following cladogram:[6][5]
The Athyriaceae in the past included Cystopteris and Gymnocarpium (now part of Dennstaedtiaceae[1]). The family has been subsumed in the family Woodsiaceae, but a Woodsiaceae defined in this way may be paraphyletic if it omits the Onocleaceae and Blechnaceae (as of 2006, the evidence was not clear).[7]
As of November 2019[update], the Checklist of Ferns and Lycophytes of the World recognizes three further genera,[8] which other sources include in Athyrium:[1][9]
Anisocampium C.Presl
Cornopteris Nakai
Pseudathyrium Newman
The genera have the following phylogenetic relationships:
Athyriaceae has a worldwide distribution, particularly the genus Athyrium.[14] Most species of Athyriaceae are medium-sized terrestrial ferns, growing in the understorey below trees and shrubs.[2]
