Athyriaceae

Athyriaceae
	Athyrium filix-femina
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Division:	Polypodiophyta
Class:	Polypodiopsida
Order:	Polypodiales
Suborder:	Aspleniineae
Family:	Athyriaceae; Alston
Type genus
	Athyrium;
Genera
	See text.

The Athyriaceae (ladyferns and allies)^[2] are a family of terrestrial ferns in the order Polypodiales. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), the family is placed in the suborder Aspleniineae, and includes two genera.^[1] Alternatively, it may be treated as the subfamily Athyrioideae of a very broadly defined family Aspleniaceae.^[3] The family has with a cosmopolitan distribution.

Description

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]

Aspleniineae (eupolypods II)

Cystopteridaceae

Rhachidosoraceae

Diplaziopsidaceae

	Aspleniaceae

	Hemidictyaceae

Thelypteridaceae

Woodsiaceae

	Onocleaceae

	Blechnaceae

Athyriaceae

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]

Genera

As circumscribed in PPG I, Athyriacae contains the following genera.^[1]

Athyrium Roth (including Anisocampium and Cornopteris Nakai)
Deparia Hook. & Grev.
Diplazium Sw.

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:

PPG I^[10]^[11]

Fern Tree of Life^[12]^[13]

Deparia

Diplazium

Athyrium s.l.

Anisocampium

	Cornopteris

	Athyrium s.s.

Deparioideae

Deparia

Athyrioideae

Ephemeropteris

Anisocampium

	Pseudathyrium

	Cornopteris

Athyrium

Diplazium

Distribution and habitat

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]