Eudicots. Eudicots, a clade strongly supported by molecular data, comprise the bulk of angiosperm species (approximately 75%; Drinnan et al., 1994). This large clade is supported by a single morphological synapomorphy–triaperturate pollen. This pollen type is unique to the eudicots, and while not all eudicots have triaperturate pollen due to subsequent changes in pollen structure, triaperturate pollen is clearly distinct from the uniaperturate pollen of basal angiosperms, monocots, and all other seed plants, allowing easy assignment of fossil pollen to the eudicots. The fossil pollen record indicates that the eudicots appeared 125 mya, shortly after the origin of the angiosperms themselves. The extensive fossil pollen collections worldwide, coupled with solid dates, make it unlikely that the eudicots arose much before this time point.