Taxonomic and evolutionary impacts of anatomical and morphological characters in the genus Epilobium L. (Onagraceae)

The genus Epilobium with about 200 species is known as a complex plant group with controversial taxonomy and species relationship. A few evolutionary studies have been performed in the genus and less is known about Epilobium speciation events in different parts of the world. The present study was performed on 18 Epilobium species growing in Iran with the aim to produce data on taxonomic implementation of morphological and anatomical features and also to study the evolutionary impacts of the same characteristics on the genus speciation. Anatomical characters were found to be of taxonomic value and could differentiate Epilobium species. The studied taxa and their replicates formed separate clades in cluster analysis. PCA revealed that quantitative anatomical characters like overall width of the xylem, and overall width of brain parenchymal, are discriminating features of the studied species. Character mapping and evolutionary signal analysis indicated the evolutionary significance of these quantitative characteristics in speciation events within Epilobium genus. Phylo heatmaps constructed for qualitative anatomical characteristics revealed an irregular and inter-mixed distribution of these characters over phylogenetic tree.

Automated summary

This study focused on 18 Epilobium species in Iran, investigating the taxonomic and evolutionary significance of anatomical and morphological features. It found that anatomical characters can help differentiate between species and play a role in speciation events within the Epilobium genus.