Further evidence for paraphyly of the Celtidaceae from the chloroplast gene matK

Based on the chloroplast matK gene sequence, a phylogenetic analysis of the Urticales in its traditional circumscription and its putative affinities p roduced three equally most parsimonious trees with tree length = 1527 steps , CI = 0.6863 and RI = 0.6352, indicating that the Ulmaceae s. l. are polyp hyletic while the Celtidaceae are paraphyletic, and particularly, Cannabis and Humulus in the Cannabaceae are consistently nested within the Celtidace ae. Therefore, the present data strongly suggest that the Cannabaceae shoul d be merged with the Celtidaceae to form a monophyletic group. According to the present study, the Celtidaceae including Cannabaceae are more closely related to the Moraceae and Urticaceae than to the Ulmaceae s. str.. Gironn iera and Aphananthe are both basal clades of the Celtidaceae rather than me mbers of Ulmaceae s. str.. The Rhamnaceae and Rosaceae are the closest rela tives of the traditional Urticales, which is very congruent with the newest system of flowering plants put forward by APG.