Molecular systematics of the eastern North American Silene (Caryophyllaceae): Evidence from nuclear its and chloroplast trnL intron sequences

摘要

This study examines the phylogenetic relationships of the nine Silene species endemic to eastern North America using nuclear ITS and chloroplast trnL intron sequence data. The ITS region is highly variable among taxa and is more phylogenetically informative than the less variable trnL intron DNA data. The ITS sequences indicate that the eastern North American taxa are not monophyletic, but instead occur in two clades that are nested within a clade including western species. Silene section Occidentales is also not monophyletic. The diverse floral morphologies of the eastern North American Silene appear to be evolutionarily labile. Neither floral morphology nor pollinator syndromes are conserved within clades. Both ITS and trnL intron data indicate that the hummingbird-pollinated taxa are not monophyletic. There is weak evidence for differences in the nuclear and chloroplast phylogenies that may be a result of reticulate evolution.