[Botany • 2024] Asplenium guodanum (Aspleniaceae) • A distinct New fern Species from northern Guangdong, China, based on morphological data and molecular phylogeny

Asplenium guodanum  

in Xu, Han, Dong, Guo, Mao et Liao, 2024.

国达铁角蕨  ||  DOI: 10.3897/phytokeys.241.122789

Abstract

A new spleenwort species, Asplenium guodanum, was found and described from Danxia landform region in Guangdong, China. The new species has close resemblance to A. subcrenatum Ching ex S.H.Wu in morphology, but can be distinguished by having plants small, stipes and rachises not covered with fibrous scales, relatively fewer pairs of pinnae, pinnae short, pinna margin weakly biserrate, pinna apex acute and lower pinnae obviously reduced. Phylogenetic analyses, based on six plastid markers (atpB, rbcL, rps4 & rps4-trnS and trnL & trnL-F) of the new species and its relatives, support a close relationship between A. guodanum and A. subcrenatum. Only one population with no more than 50 individuals were found and, therefore, it is recommended to be classified as Critically Endangered (CR) following IUCN Red List Criteria.

Key words: Conservation, Danxia landform, molecular phylogeny, species diversity, taxonomy

Macromorphology of Asplenium guodanum sp. nov.
 A habitat B habit C abaxial lamina D frond E adaxial lamina F rachis G abaxial view of pinna H adaxial view of pinna I reduced pinna base J scales at base stipe K rhizome L fiddlehead.

 Asplenium guodanum K.W.Xu & W.B.Liao, sp. nov.

 

Diagnosis: Asplenium guodanum is morphologically most similar to A. subcrenatum, but different by having small size (15–30 cm tall vs. 30–55 cm tall), rhizome scales brown to dark brown (vs. reddish-brown in A. subcrenatum), stipes and rachises not covered with fibrous scales (vs. densely covered with fibrous scales in A. subcrenatum), relatively fewer pairs of pinnae (10–15 pairs vs. 18–25 pairs), pinnae short (2–3.5 cm vs. 6–10 cm), pinna margins weakly biserrate (vs. almost entire to crenate-sinuate in A. subcrenatum), pinna apex acute (vs. acuminate in A. subcrenatum) and lower pinnae obviously reduced.

 Ke-Wang Xu, Yu-Tong Han, Yu-Ran Dong, Jian-Qiang Guo, Ling-Feng Mao and Wen-Bo Liao. 2024. Asplenium guodanum (Aspleniaceae), A distinct New fern Species from northern Guangdong, China, based on morphological data and molecular phylogeny. PhytoKeys. 241: 191-200. DOI: 10.3897/phytokeys.241.122789