New addition to the Asplenium normale complex (Aspleniaceae): an endemic forma in Taiwan

Evolutionary histories of species complexes in ferns are usually complicated with hybridization and polyploidization. In the Asplenium normale D.Don complex, we here identify a new taxon - Asplenium normale f. scythiforme Z.X. Chang, f. nov., by clarifying its position in the reticulated tree of the species complex. Our phylogenetic and flow cytometric results surprisingly support that this new taxon is a non-hybridized diploid and conspecific with A. normale. Nonetheless, the forma scythiforme can be separated from the normale by having more dissected and falcate pinnae with apices acuminate to fishbone-like tails. Currently, A. normale f. scythiforme was found to be endemic to Taiwan with only one northern and one southern populations.