Exploring the reticulate evolution in the Asplenium pekinense complex and the A. varians complex (Aspleniaceae)

Abstract

The Asplenium pekinense complex mainly comprises one diploid, A. sarelii Hook. (rare), one autotetraploid, A. pekinense Hance (best known and very common), and shares two allotetraploids, A. anogrammoides Christ (common but often misidentified) and A. altajense (Komarov) Grubov (rare and endemic) with the A. varians complex. The latter is further constituted by two diploids, A. tenuicaule Hayata (widespread) and A. semivarians Viane & Reichstein (rare), as well as other three tetraploids, A. kansuense Ching (barely known), A. varians Wallich ex Hooker & Greville (well‐known, relatively common, and morphologically variable), and A. kukkonenii Viane & Reichstein (rare and often misidentified). These two species complexes are notorious for their taxonomic difficulty based on general morphology, which is mainly caused by their history of reticulate evolution. Here, we collected most species within the two complexes, and obtained ploidy information by spore size measurement and flow cytometry investigation. Phylogenetic analyses using DNA markers representing maternally inherited chloroplast and biparentally inherited nuclear genomes helped to reconstruct the reticulate evolution history. The present results support previous hypotheses that A. sarelii is the ancestor of both A. pekinense and A. anogrammoides, as well as that A. tenuicaule is the common progenitor of A. anogrammoides, A. varians, and A. kukkonenii. We also unraveled the autotetraploid origin of A. kansuense from A. tenuicaule for the first time, and found that A. altajense shares essentially identical genomes with A. anogrammoides.

Asplenium danxiaense sp. nov. (Aspleniaceae, Aspleniineae), a new tetraploid fern species from Guangdong, China, based on morphological and molecular data

“…Conflicts between the plastid and low-copy nuclear phylogenies at species level were clearly observed in this complex. This discordance might be caused by reticulation events involving hybridization and allopolyploidization, as has been frequently documented in Asplenium (Dyer et al 2012;Fujiwara et al 2017;Chang et al 2018;Liang et al 2019Liang et al , 2021.…”

“…Asplenium L. (Aspleniaceae) is an approximately globally distributed genus comprising over 700 extant species (Kramer & Viane 1990). Reticulate evolution caused by hybridization and polyploidy has generated various species complexes that pose difficulty with species delimitation in the genus, e.g., the A. monanthes complex (Dyer et al 2012), the A. normale complex (Chang et al 2018), the A. pekinense complex, and the A. varians complex (Liang et al 2021). The A. coenobiale complex belongs to A. ser.…”

Asplenium pseudocapillipes (Aspleniaceae), a New Fern Species from South Korea

“…As a result, it can form a species complex that has morphological continuity between species [8]. To examine this morphological complexity in related taxa, many researchers have attempted to apply genome size measurement or low-copy nuclear DNA markers for genotyping analysis in ferns [9][10][11][12][13][14][15][16]. Through these attempts, new species, that were previously unknown and unrecognized due to their morphological similarities, have actually been identified [9,14,17].…”

Insight into the studies on diversity of lycophytes and ferns in China

“…, 2021 Wei XP et al, 2017;Zhao et al, 2020; Du et al, 2021; Xia et al, )和鳞毛蕨属(Dryopteris)等(Liang et al, 2021; Zuo et al, 2022)。 免 费 开 放 , 例 如 中 国 数 字 植 物 标 本 馆 (https://www.…”