Reinstatement of the endemic New Caledonian genus Thiollierea Montrouz. (Rubiaceae) necessitated by the polyphyly of Bikkia Reinw. as currently circumscribed

The genus Bikkia Reinw. as currently circumscribed comprises 20 species distributed throughout the western Pacific Ocean, with a center of diversity in New Caledonia (11 species, all but one endemic). Two recent phylogenetic studies based respectively on molecular and morphological data have shown that Bikkia s.l. is polyphyletic, comprising two lineages: coastal Bikkia from the western Pacific (including the type species of the genus, B. tetrandra (L.f.) A.Rich.) and endemic New Caledonian Bikkia, a situation that necessitates the resurrection of the generic name Thiollierea Montrouz., the oldest available for the second of these groups. An emended description is provided for Thiollierea as well as a summary of the features that distinguish it from Bikkia s.s., and seven new combinations are proposed (T. kaalaensis (N.Hallé & Jérémie) Barrabé & Mouly, T. lenormandii (N.Hallé & Jérémie) Barrabé & Mouly, T. neriifolia (Brongn.) Barrabé & Mouly, T. pachyphylla (Guillaumin) Barrabé & Mouly, T. parviflora (Schltr. & K.Krause) Barrabé & Mouly, T. retusiflora (Brongn.) Barrabé & Mouly and T. tubiflora (Brongn.) Barrabé & Mouly).