Polystichum oligodontum (subg. Haplopolystichum, Dryopteridaceae), a new cave fern from Guangxi, China

By

Nong, You
Jiang, Ri-Hong
Xiong, Chi
Wei, Qiu-Jun
Wei, Guiyuan
Ji, Xing-Yun
Lai, Ke–dao
Wei, Hongjin

Type

Article

Date of Publication

2025-11-25

Original Publication

PhytoKeys

Volume

266

Pages

297--310

Subjects

Cave ferns , coarse tooth , karst area , serration pattern

Contributed by

Pensoft Publishers

Language

English

Published by

Sofia, Bulgaria Pensoft Publishers [2010]-

Identifiers

DOI: https://doi.org/10.3897/phytokeys.266.156701

 

Abstract

<br> Polystichum oligodontum<br> (Dryopteridaceae), a new fern species in P. subg. Haplopolystichum from three karst caves in northwest Guangxi, China, is described and illustrated. This species is unique in having pinnae with a shallow or nearly free lobe on the acroscopic base and coarsely toothed distal margins. It resembles<br> P. membranifolium<br> and<br> P. kwangtungense<br> in its reflexed and oblong pinnae with an obtuse or rounded apex, but can be easily distinguished by its remote pinnae bearing a lobe at the acroscopic base. The new species also somewhat resembles<br> P. leveillei<br> in the nearly free basal lobe, but differs by its toothed upper pinna margins. Molecular phylogenetic analysis of 56<br> Polystichum<br> species, based on the<br> rbc<br> L gene, supports the placement of<br> P. oligodontum<br> within P. sect. Sphaenopolystichum, with<br> P. alcicorne<br> as its closest relative. According to the IUCN Red List Categories and Criteria, the new species is assigned to the Critically Endangered (CR) category.<br>