Morphological phylogenetic analysis of basal angiosperms: Comparison and combination with molecular data

We have amassed structural data for 108 characters and 52 taxa of magnoliids and basal monocots and eudicots, including observations by P. K. Endress and A. Igersheim on flowers. These data were analyzed separately and in combination with rbcL, 18S, and atpB sequences. Besides confirming agreements between previous analyses of both kinds of data (reduction of Magnoliales to six families; relation of Piperaceae, Saururaceae, Lactoris, and Aristolochiaceae), trees based on this data set show shifts toward molecular results (separation of Illiciaceae and Schisandraceae from Winteraceae and of Amborella, Austrobaileya, Trimeniaceae, and Chloranthaceae from Laurales; relation of Winteraceae and Canellaceae) plus continued conflicts (association of Chloranthaceae with Amborella and Trimeniaceae and of Nymphaeales with monocots). In cases where molecular and morphological trees conflict, combined analyses of morphological and molecular data generally yield the same topologies as molecular analyses, but morphology overcomes weak molecular evidence in indicating that Chloranthaceae belong just above the basal grade, that monocots are related to Piperales, and that Lauraceae are linked with Hernandiaceae. If angiosperms are rooted by molecular data, chloranthoid leaf teeth, two-trace nodes, columellar (not granular) pollen, and ascidiate carpels sealed by secretion are ancestral. Vesselless xylem is primitive in Amborella but secondary in Winteraceae and Trochodendraceae.