Ellipinema and ×Ellipisorus? Just Lepisorus (Polypodiaceae)!

Abstract

The establishment of a segregate lepisoroid fern genus Ellipinema was mainly to accommodate the isolated position of Lepisorus jakonensis (Polypodiaceae) recovered in plastid gene tree. Using newly obtained nuclear data, we recovered that Ellipinema and allied genera, such as Lepidomicrosorium, Lemmaphyllum, Neolepisorus, Paragramma, Tricholepidium and Weatherbya are deeply nested within Lepisorus. The nuclear phylogeny showing incongruent phylogenetic placement in comparison with plastid results perhaps indicated ancient hybridization events. The diagnostic morphology characterizing Ellipinema - elliptic scale-like paraphyses, which is shared by all the taxa of sect. Lepisorus and sect. Hymenophyton - falls within the range of continuous variation in the type species Ellipinema jakonense (=Lepisorus jakonensis). Our study, which integrated molecular and morphological data, demonstrates that the segregation of Ellipinema and ×Ellipisorus (= ×Lepinema Li Bing Zhang & Liang Zhang, nom. illeg.) from Lepisorus should be rejected.

Keywords: Generic delimitation; Hybridization; Lepisorus; Nuclear DNA; Paraphyses.