Sida spinosa L.

Linnaeus, C. von (1753) Species Plantarum : 683. Type: Herb. Linn. n. 866.1; lecto: LINN. Fide Borssum Walkes (1966).

Spiny sida; Sida, Spiny; Paddy's Lucerne

Flowers and fruits as a herb or a shrub up to 2 m tall.

Leaf blades about 20-90 x 6-18 mm, petioles about 3-11 mm long. Both the upper and lower leaf blade surfaces clothed in pale stellate hairs. Lateral veins 5-7 on each side if the midrib, depressed on the upper surface. Leaf blade margin toothed with 20-30 teeth on each side. Stipules linear about 3-7 mm long, densely clothed in stellate hairs.

Peduncles (petioles) pulvinate. Calyx tube ribbed, about 4-5 mm long, lobes about 4-05 mm long. Petals about 8-20 mm long, +/- free or attached to one another only at the base by way of the androgynophore. Stamens fused to form a column around the ovary and style. Free staminal filaments about 0.75-2 mm long, anthers about 0.5-0.75 x 1 mm. Ovary about 1.5-2 mm long. Styles 6-8, each about 6-10 mm long, fused together at the base. Locules about 6-8. Ovules 1 per locule.

Fruits wider than long, about 5 mm diam., consisting of 10 mericarps. Fruits enveloped in the persistent calyx, calyx about 7-8 mm long, longitudinally ribbed and densely clothed in stellate hairs. Each mericarp about 2 mm long with two horns each about 1 mm long at the apex. Horns with a few hairs near the apex. Seeds irregularly shaped about 2-2.2 x 1.5 mm, pointed at one end.

Features not available.

Occurs in WA, NT, CYP, NEQ, CEQ and southwards as far as coastal central New South Wales. Altitudinal range in northern Australia from near sea level to 850 m. Often a weed of agricultural land, also found in vine thicket, disturbed monsoon forest and rain forest margins. Found throughout the tropics in the rest of the world.