An expanded circumscription and new infrageneric classification of Rinzia (Myrtaceae: Chamelaucieae)

The circumscription of Rinzia Schauer (Myrtaceae tribe Chamelaucieae DC.) is enlarged to encompass species with varied stamen arrangement, filament width and seed morphology. This revision of Rinzia s. lat. is based on both morphological and molecular evidence, and establishes five sections within the genus, Discolora Rye, Mesostemon Rye, Polyandra Rye, Semasperma Rye and the typical section. All sections occur in Western Australia, with three of them endemic to the south-west, while sect. Polyandra also occurs in central Australia and sect. Semasperma also occurs in south-eastern Australia. Three new combinations are made for species previously included within Baeckea L., and the new name R. orientalis Rye is published for B. crassifolia Lindl. Baeckea crassifolia var. icosandra F.Muell. ex Benth. is raised to species rank as R. icosandra (F.Muell. ex Benth.) Rye. The other new combinations are R. ericaea (F.Muell. ex Benth.) Rye and R. polystemonea (F.Muell.) Rye. Four new Western Australian species are described as R. fimbriolata Rye & Trudgen, R. medifila Rye, R. torquata Rye & Trudgen and R. triplex Rye & Trudgen, and a new subspecies from Kangaroo Island, South Australia, as R. ericaea subsp. insularisRye. Rinzia morrisonii Trudgen is reduced to synonymy under R. longifolia Turcz. Lectotypes are selected for Baeckea ericaea F.Muell. ex Benth. and R. morrisonii. Seven Western Australian species have conservation priority.