Figure 3.

Summary of the number of observed transitions between mating systems. This minimum number of transitions was counted after assigning each ancestor to the most likely state. We treated the origin of selfing in Pleodorina japonica, Pleodorina californica, and Volvox aureus as one transition, although the ancestral state of the ancestor to these three species is ambiguous. Three homothallic species break apart into unicells during sexual differentiation preventing assignment to monoecy or dioecy (unknown-ecious homothallism).