Polyploidy and the formation of species diversity in Aspleniaceae

Abstract

Ferns are considered to have the highest frequency of polyploidy in plants. Based on the published cytological data of 188 species, we analyzed the relationship between polyploidy and the formation of species diversity in the fern family Aspleniaceae, which comprises approximately 800 species. The results show that polyploids, including triploids, tetraploids, hexaploids, octoploids, decaploids, dodecaploids and hexadecaploids, have been documented in the family. Of the 188 Aspleniaceae species with cytological data, 88.8% exhibit polyploidy, 41.0% show intraspecific polyploidy and 47.9% are the result of polyploid speciation. In addition, the diverse ploidy levels suggest that these species have a complex evolutionary history and their taxonomic problems require further study. The perplexity and future directions of study of Aspleniaceae were also discussed.