Alexgeorgea, a bizarre new genus of Restionaceae from Western Australia

Abstract

The genus Alexgeorgea is described as new to science. Two species were discovered during field work in 1974: A. subterranea, from the Jurien Bay-Badgingarra sandplain, W.A., and A. arenicola, from sand areas short distances north and east of Perth. Alexgeorgea is highly distinctive in bearing single-flowered female inflorescences on sessile horizontal rhizomes c. 10-15 cm below the sand surface. In flower, only the tips of the bracts and the three ephemeral styles appear above the ground, so that female flowers are invisible most of the year and inconspicuous even at anthesis. Fruits are exceptionally large for Restionaceae, indehiscent, one-seeded and borne sessile on underground rhizomes. Difficulty in dispersal of these fruits would explain the existence of presumptive all-female colonies of A. arenicola which may have originated from single-fruit introductions to sites at the periphery of the range of that species. Increase in the size of colonies is mostly vegetative, by branching of the elongate subterranean rhizomes. It is suggested that the underground flowering and fruiting habit is related to fire resistance. Alexgeorgea appears most closely related to Western Australian species of Restio on account of striking vegetative similarities. The two species of Alexgeorgea are illustrated by habit photographs and macrophotographs of living plants taken during the field work.