Phylogenetic analysis of Ulmaceae

Abstract

A phylogenetic analysis of the Ulmaceae, Cannabaceae, Barbeyaceae, and Broussonetia of the Moraceae produced nine equally parsimonious trees with 127 steps. The Ulmoideae (Ulmaceae, sensu GRUDZINSKAYA) are a monophyletic group and distinct from the Celtidoideae. The genus Ampelocera occupies an isolated taxonomic position among the celtidoids. The similarity of Ampelocera to the fossil celtidoid flower Eoceltis of North America suggests that Ampelocera posesses an archaic suite of characters, and occupies a primitive position among the celtidoids, the Cannabaceae and the Moraceae. The relationships among the other celtidoid taxa. Cannabaceae. and Broussonetia are problematic. The Cannabaceae and Broussonetia of the Moraceae are nested within the celtidoids suggesting that this is a paraphyletic group. The close, but unresolved, relationship of the celtidoids to the Moraceae and Cannabaceae observed in this analysis, and the appearance of the celtidoids in the fossil record prior to the ulmoids suggests that the evolutionary relationship of the ulmoids and celtidoids may be more distant than current taxonomic treatments reflect.