A revision of the genus Notothixos (Viscaceae)

Abstract

Notothixos is a genus of eight species distributed from Ceylon, Lower Burma and the Philippines southwards and eastwards through the Malesian region to Santa Cruz Islands and south-eastern Australia. It is distinguished by a dense and conspicuous indumentum of dendritic, stellately branched or peltate hairs or scales, and by lateral stems subtended by two prophylls and two cataphylls. The basic inflorescence unit is a small cymose cluster subtended by a pair of small bracts, and conflorescence evolution has involved the aggregation of cymules, and development of indeterminate conflorescences from determinate ones. The entire genus has not been revised previously; four names are reduced to synonymy of others for the first time here. Notothixos curranii Merrill, N. merguiensis Danser and N. spicatus Krause are conspecific with N. floccosus (Thw.) Hook.f, and N. schlechteri Krause is conspecific with N. leiophyllus Schumann. New chromosome numbers are reported for two species: N. incanus (n= 13) and N. subaureus (n = 12). Evidence suggests that the genus originated in the Malesian region, and that it has reached Papuasia and Australia as part of an intrusive element following Miocene collision of the Australian and Sunda plates.