Hymenasplenium

Hymenasplenium is one of three genera of ferns in the Aspleniaceae (spleenwort family), in the eupolypods II clade of the order Polypodiales.^[1][2] The others are Hemidictyum and Asplenium. Hymenasplenium was segregated because it is a natural grouping with differing rhizome morphology – dorsiventral v. radial for the rest of Asplenium, differing chromosome count – x=39 v. x=36 for the rest of Asplenium, and a clear monophyletic grouping based on genetic analysis. It was confirmed as a sister group to Asplenium in a 2015 molecular study of the genera.^[3]

Hymenasplenium
Hymenasplenium cheilosorum
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Division:	Polypodiophyta
Class:	Polypodiopsida
Order:	Polypodiales
Suborder:	Aspleniineae
Family:	Aspleniaceae
Genus:	Hymenasplenium Hayata
Type species
Hymenasplenium unilaterale (Lam.) Hayata. 1927
Synonyms
Asplenium section Hymenasplenium (Hayata 1927) Iwatsuki 1975 Asplenium (Hymenasplenium) (Hayata 1927) Bir 1998 Boniniella Hayata 1927 Asplenium series Unilateralia Ching & Wu 1989

Phylogeny

Phylogeny from Fern Tree of Life[4][5]

Other species include:

Hymenasplenium H. delitescens (Maxon) Regalado & Prada H. hoffmannii (Hieronymus) Regalado & Prada H. laetum (Swartz) Regalado & Prada H. praestans (Copeland) Testo, Riibe & Sundue H. triquetrum (N.Murak. & Moran) Regalado & Prada H. riparium (Liebmann) Regalado & Prada H. volubile (N.Murak. & Moran) Regalado & Prada H. phamhoanghoi Zhang, Xu & Luong H. excisum (Presl) S.Linds. 2009 (Scalloped spleenwort) H. obscurum (Blume) Tagawa H. tholiforme Zhang, Ju & Xu H. pseudobscurum Viane H. obtusidentatum Chang & Zhang H. cheilosorum H. amoenum (Presl ex Mettenius) Ranil H. filipes (Copeland) Sugim. H. obliquissimum (Hayata) Sugim. H. szechuanense (Ching) Viane & Dong H. furfuraceum (Ching) Viane & Dong H. latidens (Ching) Viane & Dong H. quercicola (Ching) Viane & Dong H. subnormale (Copeland) Nakaike H. wildii (Bail.) Ohlsen H. distans Zhang, Xu & Zhang H. apogamum (N.Murak. & Hatan.) Nakaike H. ngheanense Zhang, Xu & Lu H. laterepens N.Murak. & Cheng ex Chang & Hori H. unilaterale (Lam.) Hayata H. cardiophyllum (Hance) Nakaike H. quangnamense Zhang, Xu & Zhang H. hastifolium Xu, Zhang & Liao H. pubirhizoma (Ching & Liu) Xu & Zhang H. chingii Xu, Zhang & Liao H. wangpeishanii Zhang & Xu H. hondoense (N.Murak. & Hatan.) Nakaike H. speluncicola Zhang, Xu & He

H. andohahelense Viane H. antsirananense Viane H. basiscopicum (Moran & Sundue) Regalado & Prada H. changputungense (Ching) Viane & Dong H. denticulatum Xu, Zhang & Liao H. ×doanyense Viane H. ×excurum Viane H. guineense Zhang, Liao & Xu H. ikenoi (Makino) Viane H. ×incisoserratum (Rosenstock) H. inthanonense N.Murak. & J.Yokoy. H. kenyense Zhang, Xu & Kamau H. kinabaluense Zhang & Xu H. madagascariense Zhang, Liao & Xu H. neocaledonicum Zhang & Xu H. nigricostatum Zhang & Xu H. obtusifolium (von Linné) Regalado & Prada H. ofeliae (Salgado) Barcelona & Pelser 2021 H. oligosorum Zhang, Xu & Lorence 2019 H. ortegae (N.Murak. & Moran) Regalado & Prada H. perriei Zhang & Xu 2018 H. purpurascens (Mettenius ex Kuhn) Regalado & Prada H. queenslandicum Zhang & Xu 2019 H. repandulum (Kunze) Regalado & Prada H. rivulare (Fraser-Jenkins) Viane & Dong H. sabahense Zhang, Xu & Chen H. samoaense Zhang, Xu & Wood H. sinense Xu, Zhang & Liao H. solomonense Zhang & Xu H. trapeziforme (Wallich ex Roxburgh) H. vanuatuense Zhang & Xu H. wusugongii Zhang, Liao & Xu