Maesa tetrandra (Primulaceae) in Palau: An Introduced Species Mistaken for a Single-Island Endemic1

Maesa canfieldiae Fosberg & Sachet was formerly recognized as a single-island endemic in the Palau archipelago with a potentially rare distribution warranting its listing on the IUCN Red List as Vulnerable. Here we synonymize M. canfieldiae into Maesa tetrandra (Roxb.) A. DC., a more widespread species native to Indonesia and New Guinea, and discuss its likely method of recent introduction to the Palau Islands. Because this particular species favors disturbance and is now considered naturalized in the Pacific, we have included a general description of the plant to aid in its identification by nonexperts and to allow monitoring of its invasive potential. We recommend the listing of M. tetrandra as Least Concern on the IUCN Red List.