Woodsiaceae

Woodsiaceae formerly included the members of the families Athyriaceae and Diplaziopsidaceae, but analysis has consistently shown that they should be treated as separate families.^[6] The following cladogram for the suborder Aspleniineae (as eupolypods II), based on Lehtonen (2011),^[7] and Rothfels et al. (2012),^[8] shows a likely phylogenetic relationship between the Woodsiaceae and the other families of the Aspleniineae.

A molecular phylogenetic study published in 2020 largely confirmed the position of the family. It included 122 accessions representing about 43 species then placed in the sole genus Woodsia. It showed that Woodsia was deeply divided into two clades, which the authors recognized as two genera Physematium and Woodsia.^[4]

As of June 2023^[update], World Ferns accepted three genera:^[2]

• Physematium Kaulf.
• Woodsia R.Br.
• ×Woodsimatium Li Bing Zhang, N.T.Lu & X.F.Gao = Woodsia × Physematium

Species of Woodsia are native to northern North America and Eurasia, and further south in the east of Asia, from western mainland China to Taiwan. Although the distributions overlap, species of Physematium generally have a more southern distribution, being found further south in North America and in northern South America as well as in Asia, with a few species in Africa and Madagascar.^[4]