Opercularia
Subshrubs or herbs, perennial, often slightly woody at base, characteristically foetid when crushed. Leaves opposite; stipules connate to leaf-bases and forming a sheath around nodes, toothed. Inflorescence terminal or in forks of branches, bracteate subglobose heads. Flowers sessile, usually bisexual, sometimes unisexual and then plants dioecious; calyx 3–5-lobed, persistent in fruit; calyx-tubes connate; corolla 3–5-lobed, deciduous, white or greenish, tube longer than lobes; stamens 1–5, usually 4, inserted at base of corolla-tube, anthers exserted, with a terminal appendage; ovaries inferior, 1- or 2-celled, partially or completely fused, ovules 1 per cell, style usually 2-lobed, stigmas linear. Fruit a head of united, 2-valved capsules, each dehiscing by the abscission of the apical lid, or several lids more or less united and shed as a single unit.
An endemic Australian genus of 18 species (11 species endemic to south-west Western Australia) (Markey 2018).
Jeanes, J.A. (1999). Rubiaceae. In: Walsh, N.G.; Entwisle, T.J., Flora of Victoria Vol. 4, Cornaceae to Asteraceae, pp. 616–642. Inkata Press, Melbourne.
SpinningMarkey, A.S. (2018). By their fruit you will recognise them: species notes and typifications in Western Australian species of Opercularia (Rubiaceae: Anthosperminae). Nuytsia 29: 119–140.
