CLADISTICS OF THE MAGNOLIIDAE

Abstract

A cladistic resolution is presented for the origin of the angiosperms based on a parsimony analysis of 49 taxa of Magnoliidae. Hamamelidae and Alismatidae, with gymnospermous outgroup comparisons for the polarization of 104 characters. The Magnoliidae is recognized as a paraphyletic assemblage of nine orders: Calycanthales, Magnoliales, Laurales, Illiciales, Lactoridales. Ranunculales, Aristolochiales, Piperales and Nymphaeales. The Calycanthaceae and Idiospermaceae are segregated as the new order Calycanthales, which is hypothesized to be the archetype for angiosperms. Excluding Winteraceae and Lactoridaceae, the Magnoliales is monophyletic. The Austrobaileyaceae is a first branch of Magnoliales, rather than lauralean. Excluding Amborellaceae and Calycanthales, the Laurales is monophyletic. The Chloranthaceae is a first branch of Laurales, rather than piperalean. The Amborellaceae and Winteraceae are early branches of Illiciales. The Lactoridaceae is isolated as the Lactoridales. Including Papaveraceae, the Ranunculales is monophyletic, with Lardizabalaceae as a first branch. The Ranunculales is more closely related to the Hamamelidae, forming the clade Tricolpates. The Aristolochiales, Piperales and Nymphaeales are successively more closely related to the Alismatidae, forming the clade Paleoherbs. The Nelumbonaceae are nymphaealean Paleoherbs, rather than Tricolpates. The Lactoridaceae is not a Paleoherb. These results support many aspects of the strobilar-flower hypothesis for the origin of the angiosperms, as well as the plesiomorphic character states of woody shrubs with simple, pinnatelyveined leaves.