Phylogenetic definitions for Dipsacales, Adoxaceae, and Caprifoliaceae

Formal phylogenetic definitions are here provided for the angiosperm clades Dipsacales, Adoxaceae, and Caprifoliaceae. After decades of progress in understanding the phylogeny of Asteridae and Campanulidae, the three clades here associated with those three names are better supported than ever, and the phylogenetic definitions presented here therefore differ little from the pre-PhyloCode phylogenetic definitions provided 25 years ago by Donoghue et al. (2001). It is abundantly clear that Dipsacales is a clade composed of two very well-supported and easily identified sister clades—here Adoxaceae and Caprifoliaceae—that were not recognized in pre-phylogenetic angiosperm classification systems. The impetus for solidifying these names now under the PhyloCode is that decisions made in the past decade by the Nomenclatural Committee for Vascular Plants of the International Code of Nomenclature for algae, fungi, and plants (ICN) have led to the mandatory replacement of the name Adoxaceae by Viburnaceae for a family that includes Viburnum, Sambucus, and Adoxa. This unfortunate decision to replace a widely accepted name, used many thousands of times in the literature, by a name that has rarely been used, can now be circumvented (by those who wish to do so) by correctly observing that Adoxaceae is the accepted name for this clade under the PhyloCode. This paper prepares the way for a comprehensive phylogenetic classification and nomenclature of both Adoxaceae and Caprifoliaceae.