Description from Flora of China
Malva americana Linnaeus, Sp. Pl. 2: 687. 1753; M. spicata Linnaeus; Malvastrum spicatum (Linnaeus) A. Gray; Melochia spicata (Linnaeus) Fryxell; Sphaeralcea americana (Linnaeus) Metz.
Herbs, perennial, or subshrubs, 0.5-1(-3) m, most parts principally stellate pubescent, also with some simple hairs. Stipules filiform, 4-5 mm; petiole 0.5-3.5 cm; leaf blade ovate to oblong, rarely slightly 3-lobed, 2-6(-7) × 1.2-4(-6) cm, both surfaces stellate pubescent, base acute, obtuse, or truncate to slightly cordate, margin serrate, apex acute to acuminate. Flowers congested into a dense short terminal spike, 1.5-3(-10) × ca. 1 cm, usually only 1 flower open at a time. Epicalyx lobes filiform to lanceolate, acuminate, 8-10 × 1.5-2.5 mm, abaxially hispid with simple or bifurcate hairs and minute stellate hairs, adaxially glabrous. Calyx shallowly cup-shaped, 5-6 mm in diam., accrescent to 6-10 mm in fruit, lobes triangular, ca. 4 × 3 mm, abaxially densely hirsute, adaxially minutely stellate pubescent, apex acuminate. Corolla yellow, 1.3-1.7 cm in diam.; petals obliquely obovate, claw stellate ciliate, apex asymmetrically emarginate. Filament tube 2-3 mm, stellate pubescent. Mericarps (5-)8-15(-18), nearly orbicular, (1-)2-2.5 × 1.5-3(-5) mm in diam., cusps absent, endoglossum usually present, minute. Seeds gray, reniform, 1.2-1.7 mm in diam., glabrous.
Chinese material can be referred to Malvastrum americanum var. americanum. Malvastrum americanum var. stellatum S. R. Hill is restricted to Australia.
Weed of semi-arid areas. Fujian, Taiwan [India, Indonesia, Philippines; Australia, North and South America; naturalized pantropical weed].