Wilczekra, a New Genus of Celastraceae for a Disjunct Lineage of Euonymus

摘要

Disjunct distributions in poorly defined taxa can serve as indicators that the members of the isolated ranges are polyphyletic, as has been previously demonstrated in many plant families. Such taxa should be prioritized for inclusion in phylogenetic analyses so that at least one member from each isolated range should be sampled together with other closely related taxa. We describe a new monotypic genus (Wilczekra) for Euonymus congolensis, which is the only species of Euonymus reported in mainland Africa other than one other species (E, latifolius) whose range extends from Europe into northern Africa. We infer that Wilczekra congolensis is the sole African member of an early-derived lineage of Celastraceae that is most diverse in the Austral-Pacific but also includes Crossopetalum from the West Indies and tropical America.