Molecular, chromosomal, and morphological evidence reveals a new allotetraploid fern species of Asplenium (Aspleniaceae) from southern Jiangxi, China Author Lin, Chen-Xue Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing, 510275, China Author Xu, Guo-Liang Jiulianshan National Nature Reserve Administrative Bureau, Longnan, 341700, China Author Jin, Zhi-Fang Jiulianshan National Nature Reserve Administrative Bureau, Longnan, 341700, China Author Liao, Wen-Bo State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China lsslwb@mail.sysu.edu.cn Author Xu, Ke-Wang Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing, 510275, China xukw10@njfu.edu.cn text PhytoKeys 2022 2022-06-09 199 113 127 http://dx.doi.org/10.3897/phytokeys.199.81292 journal article http://dx.doi.org/10.3897/phytokeys.199.81292 1314-2003-199-113 1F73F6549FA75C5DBD7080DC0B852878 Asplenium jiulianshanense K.W.Xu & G.L.Xu sp. nov. Figs 1 , 2 , 5 Diagnosis. Asplenium jiulianshanense somewhat resembles A. kiangsuense by its small size, rachises adaxially without a deep furrow, pinnae elliptic to trapeziform-oblong, sori 3-4 per pinna in the middle part of frond. However, the former has rachises with only one gemma near apex, pinnae (15-)20-35 pairs, pinna margins entire to sparsely crenate, exospore length 37-43 μm , while the latter has rachises without gemmae near the apex, pinnae 8-20(-22) pairs, pinna margins entire to sinuate, exospore length 31-36 μm . Type . China . Jiangxi province , Ganzhou City , Jiulianshan National Nature Reserve , 256 m , 24°56'2.04"N , 114°49'23.44"E , 8 Jun 2021 , Guo-Liang Xu & Ke-Wang Xu XKW681 ( holotype , NF!; isotype, SYS!) . Description. Plants 8-15 cm tall. Rhizome erect, short, apex densely scaly; scales narrowly triangular to linear-subulate, purplish-black, 2-3 x 0.4-0.6 mm. Fronds caespitose; stipe castaneous-brown to purplish-black, shiny, terete, 1-3 cm, glabrous; lamina linear, 8-12 x ca. 1.2 cm, apex acute, 1-pinnate; pinnae (15-)20-35 pairs, lower ones subopposite, hardly reduced, middle pinnae spreading horizontally or slightly reflexed, elliptic to trapeziform-oblong, 3-6 x 3-5 mm, base asymmetrical, acroscopic side truncate and close to rachis, basiscopic side narrowly cuneate, shortly stalked to subsessile, margin entire to sparsely crenate, apex obtuse. Venation anadromously pinnate or with first basiscopic vein lacking, costa with 2 or 3 acroscopic veins, obscure, veins simple or 1-forked. Fronds papery, grayish-green when dry; rachis castaneous-brown to purplish-black, shiny, glabrous, semiterete, and adaxially flat or with 2 slightly raised lateral ridges, often gemmiferous near the apex. Sori (1-)3-4(-6) per pinna, linear-elliptic, ca. 1 mm in length, median on subtending vein; indusia grayish-green, elliptic, membranous, entire, and opening toward costa. Spores with lophate perispore, average exospore length 37-43 µm . Etymology. Based on the Chinese pinyin, Jiulianshan, the name of the National Nature Reserve in southern Jiangxi, China, referring to the type locality of the species. Vernacular name. 九连山铁角蕨 ( jiǔ-lian-shan tie-jiǎo-jue ). Geographical distribution and habit. Asplenium jiulianshanense is known only from a single locality in Mount Jiulianshan, Jiangxi, China, where there have been multiple collections. It was observed to grow on cliff rocks under shrubs at an elevation of ca. 200 m in subtropical evergreen broad-leaved forest. Conservation. We provisionally assess A. jiulianshanense as Endangered based on criterion D of IUCN (2012) . Only one population of the new species was found at type locality with no more than 250 mature individuals. Cytology. The chromosome number of A. jiulianshanense is 2n = 144 (Fig. 6 ). The chromosome number of A. jiulianshanense indicates that the new species is a tetraploid species. Additional specimens examined. China . Jiangxi province , Ganzhou City , Jiulianshan National Nature Reserve , 256 m , 24°56'2.04"N , 114°49'23.44"E , 10 Jul 2021 , Guo-Liang Xu & Ke-Wang Xu XKW685 (NF!); the same collection information, Guo-Liang Xu & Ke-Wang Xu XKW686 (NF!) .