Decisiveness and phylogenetic groves. Pattern of taxon coverage shown is not decisive for any tree but is a phylogenetic grove sensu Ané et al. . There are five binary trees like the tree in the lower right, which differ only in the placement of taxon C (two of these are indicated by alternative placements of dashed lines). Although taxon coverage is not decisive for any of the five trees, there is no ambiguity about the relationships of the five trees if taxon C is ignored. Example modified from [56, 57].