Revision of endemic Marquesas Islands Bidens (Asteraceae, Coreopsideae)

Abstract

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: B. 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., B. evapelliana W.L. Wagner, J.R. Clark & Lorence, sp. nov., and B. wichmanii W.L. Wagner, J.R. Clark & Lorence, sp. nov. from the undercollected island of Fatu Hiva. In addition to these new species, we recognize the following six species of Bidens previously described from the Marquesas Islands: Bidens beckiana (F. Br.) Sherff (Eiao and Hatutaa), B. bipontina Sherff and B. cordifolia Sch. Bip. (both in Nuku Hiva), B. henryi Sherff (Hiva Oa, Tahuata), B. uapensis (F. Br.) Sherff (Ua Pou), and B. polycephala Sch. Bip. (Nuku Hiva, Ua Huku, Hiva Oa, Tahuata, and Mohotani). Two names are reduced to synonymy under B. polycephala: B. collina Degener & Sherff, syn. nov. and B. jardinii Sch. Bip., syn. nov. Bidens polycephala has the widest distribution of the Marquesan species on five of the islands and exhibits considerable variation.