Sida arsiniata R.M.Barker

Nuytsia 17:26-29, Figs 3-4a (2007)
Conservation Code
Not threatened
Naturalised Status
Native to Western Australia
Name Status

Monoecious, small spreading shrub, to 0.5 m high. Red sand. Dunes.

Amanda Spooner, Descriptive Catalogue, 31 March 2008

Scientific Description

Herb or shrub. Stems hairy. Leaves 12-70 mm long, 3-25 mm wide, not lobed; margins crenate; indumentum present, with stellate hairs; stipules present and persistent to older leaves or present but early deciduous (only visible on youngest leaves), 8-10 mm long. Perianth clearly of two whorls (calyx and corolla), the corolla obvious and prominent. Pedicel present, 7-15 mm long; indumentum present, with stellate hairs. Epicalyx (extra segments or 'bracteoles' immediately below the calyx) absent. Calyx green, 6-13 mm long, the lobes fused half or more of their length, stellate hairs present. Corolla yellow, 5-7 mm long, glabrous. Stamens many, united and arising from a staminal tube around the style; filaments present, 1-2.2 mm long; anthers 0.3-1 mm long. Ovary hairs and scales absent (ovary quite glabrous); style 1, 2.8-4 mm long, with four or numerous style branches or lobes, mostly glabrous. Fruits indehiscent and splitting into sections (schizocarps), length-width ratio more or less as long as wide, mericarps wrinkled, hairs and scales absent; apex distinctly flat-topped; calyx persistent to mature fruit, not accrescent; carpels 12; seeds per loculus 1. Flowering time May, July, August or September. Distribution Botanical Province Eremaean, IBRA Bioregion Pilbara.

C. Hollister and K.R. Thiele, 15 January 2020


IBRA Regions
Carnarvon, Pilbara.
IBRA Subregions
Cape Range, Chichester, Fortescue, Hamersley, Roebourne.
Local Government Areas (LGAs)
Ashburton, East Pilbara, Karratha.