Although molecular phylogenetic analyses refute morphological cladistic inferences that angiosperms are related to Gnetales and leave angiosperm outgroup relationships as unclear as ever, they provide increasingly strong evidence on rooting of the angiosperms, with Amborella, Nymphaeales, and a clade including Illiciales, Trimeniaceae, and Austrobaileya as the first three branches of the angiosperm tree, possibly followed by Chloranthaceae. These results suggest that previously reported similarities between pre-Albian angiosperms and these taxa are more significant than originally recognized, whether as confirmation of molecular results or as evidence that the Early Cretaceous radiation may be close to the origin of crown-group angiosperms. Similarities between Aptian leaves and the presumed basal lines include chloranthoid teeth and variable stomata, as noted by Upchurch. According to molecular phylogenies, the first angiosperms had columellar exine structure, and a reticulate tectum arose soon after, whereas the supposedly primitive granular and "atectate" exines of Magnoliales are derived. This is further evidence against the homology of granular exine structure in Bennettitales, Gnetales, and angiosperms. Thus the reticulate-columellar monosulcates that dominate Hauterivian, Barremian, and Aptian angiosperm pollen floras need not have been preceded by long phase with granular monosulcates. Hauterivian verrucate monosulcates described by Hughes as "CACTISULC", which resemble pollen of Amborella, could represent the pre-reticulate stage. Molecular trees imply that ascidiate rather than plicate carpels are ancestral, and exotestal seeds are common in the basal lines; this is consistent with the abundance of such carpels and seeds in the oldest Cretaceous mesofloras described by Friis and others. Groups appearing in the Albian belong to more deeply nested "magnoliid" clades and the first few lines of eudicots in molecular phylogenies (Ranunculales, Nelumbonaceae, Platanaceae, Buxales).

Key words: angiosperms, Cretaceous, molecular systematics, paleobotany