During the preparation of the Vascular Flora of the Marquesas Islands four new species of Bidens (Coreopsideae, Asteraceae) have come to light and are described herein: Bidens woodii W.L. Wagner, J.R. Clark & Lorence, sp. nov. from Ua Pou, and Bidens microcephala W.L. Wagner, J.R. Clark & Lorence sp. nov., Bidens evapelliana W.L. Wagner, J.R. Clark & Lorence, sp. nov., and Bidens wichmanii W.L....