Urticalean Rosids: Circumscription, Rosid Ancestry, and Phylogenetics Based on Rbcl, Trnl-F, and Ndhf Sequences1
American Journal of Botany 89(9): 1531±1546. 2002. URTICALEAN ROSIDS: CIRCUMSCRIPTION, ROSID ANCESTRY, AND PHYLOGENETICS BASED ON RBCL, TRNL-F, AND NDHF SEQUENCES1 KENNETH J. SYTSMA,2,9 JEFFERY MORAWETZ,2,4 J. CHRIS PIRES,2,5 MOLLY NEPOKROEFF,2,6 ELENA CONTI,2,7 MICHELLE ZJHRA,2,8 JOCELYN C. HALL,2 AND MARK W. C HASE3 2Department of Botany, University of Wisconsin, Madison, Wisconsin 53706 USA, and 3Molecular Systematics Section, Royal Botanic Gardens, Kew, UK To address the composition of the urticalean rosids, the relationships of the component families (maximally Cannabaceae, Cecro- piaceae, Celtidaceae, Moraceae, Ulmaceae, and Urticaceae) and analyze evolution of morphological characters, we analyzed sequence variation for a large sampling of these families and various rosid outgroups using rbcL, trnL-F, and ndhF plastid regions. Urticalean rosids are derived out of a lineage including Barbeyaceae, Dirachmaceae, Elaeagnaceae, and Rhamnaceae, with Rosaceae less closely related; thus, they are imbedded within Rosales. Ulmaceae are the sister to all remaining families. Cannabaceae are derived out of a subclade of Celtidaceae; this expanded family should be called Cannabaceae. Cecropiaceae are derived within Urticaceae and are polyphyletic with Poikilospermum derived elsewhere within Urticaceae; this expanded family should be called Urticaceae. Monophy- letic Moraceae are sister to this expanded Urticaceae. Support for these relationships comes from a number of morphological characters (¯oral sexuality, presence or absence of hypanthium, stamen type and dehiscence, pollen pore number, ovule position, and embryo alignment) and chromosome numbers. Most fruit types, in terms of ecological dispersal, are derived independently multiple times and are strongly correlated with habitat.
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