Within the association two variants could be distinguished depending on the occurrence of Asplenium viride and Gymnocarpium fedtschenkoanum.
Asplenio-Cystopteridetum Cf fragilis Oberdorfer 1938 - variant with Asplenium viride - variant with Gymnocarpium fedtschenkoanum Association 2.
jessoense, and Dryopteris fragrans.
Molecular work by Schuettpelz and Pryer (2007), using three plastid genes, revealed two members of the Woodsiaceae, Gymnocarpium
(not present in the Hawaiian Islands) and Cystopteris, to be paraphyletic and sister to the eupolypods II.
Except for one trip, a trip that is a favorite memory that still makes me smile, to a special Gymnocarpium collecting site in Wellington County, near Guelph, to which we returned a few times to collect chromosome and spore material.
A paper presenting a molecular phylogeny of Cystopteridaceae (including Cystopteris and Gymnocarpium, two of DMB's favorite ferns), and currently in press at Systematic Botany (Rothfels et al.
Mating system and distribution of genetic variation in Gymnocarpium
dryopteris subsp, disjuncture.
In the rbcL tree, all four Rhachidosorus specimens are united in a single clade; two species of Diplaziopsis form another monophyletic clade with Homalosorus; the three genera of Woodsia, Prowoodsia and Cheilanthopsis (Woodsiaceae II) are united in a single clade; and the three genera of Cystopteris, Acystopteris and Gymnocarpium
(Woodsiaceae III) are united in another one.
Ecology, syntaxonomy and population size of Gymnocarpium
dryopteris have been studied, especially during the period 1979-1991 by collecting data on 419 colonies in the Kuinderbos (a planted woodland in the Noordoostpolder, a polder reclaimed from the former Zuiderzee in 1942) and 74 colonies elsewhere in the Netherlands.