Hymenasplenium is one of two genera in the nearly globally distributed and species-rich fern family Aspleniaceae. Researchers have previously recognized Hymenasplenium laterepens, a triploid taxon from China, but did not publish this finding or designate a type specimen.
Researchers from Xishuangbanna Tropical Botanical Garden (XTBG) collected and studied the triploid taxon at the classical place in Xishuangbanna and got it published in Phytotaxa.
To clarify its taxonomic status, the researchers studied the morphological differences between the new species and related species and investigated the distinction of the putative species. They investigated both chloroplast and nuclear DNA sequences for the members of the monophyletic clade of the paleotropical Hymenasplenium genus
Molecular phylogenetic analyses and morphological observation of H. laterepens and related species clearly indicate that it is a distinct taxonomic entity worthy of species rank.
Hymenasplenium laterepens is similar to H. apogamum. However, H. laterepens has larger triangular lamina, pinnae acute at the apex and more deeply serrated on the margin, and long creeping rhizome with thicker roots.
H. laterepens is currently known to coexist with H. apogamum in southeastern China in soil or on rocks near streams in shaded forests at elevation of 200–800 m.
The type specimen was collected from Bubeng, Mengla County, Xishuangbanna, at an elevation of 580 meters and preserved at Herbarium of XTBG.
CHANG Yanfen Ph.D
Center for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China