Phylogenetic relationships of Polemoniaceae inferred from 18S ribosomal DNA sequences

Cladistic analyses of chloroplast DNA disagree with current classifications by placing Polemoniaceae near sympetalous families with two staminal whorl s, including Fouquieriaceae and Diapensiaceae, rather than near sympetalous families with a single staminal whorl, such as Hydrophyllaceae and Convolv ulaceae, To explore further the affinities of Polemoniaceae, we sequenced 1 8S ribosomal DNA for eight genera of Polemoniaceae and 31 families represen ting a broadly defined Asteridae. The distribution of variation in these se quences suggest some sites are hypervariable and multiple hits at these sit es have obscured much of the hierarchical structure present in the data. Ne vertheless, parsimony, least-squares minimum evolution, and maximum likelih ood methods all support a monophyletic Polemoniaceae that is placed near Fo uquieriaceae, Diapensiaceae and related "ericalean" families.