Cinderella weed

S. nodiflora is an erect branched ephemeral herb usually 30-80 cm tall. The shallow root system is usually strongly branched.

The erect or ascending, sometimes woody stems, branch dichotomously from the base of the plant; they tend to have long internodes and swollen nodes, to be rounded or slightly angular in section, smooth, often finely hairy, and usually about 50 cm tall. The lower parts of the stems may root at the nodes, especially in damp conditions.

The leaves occur in opposite pairs and are 4-9 cm long, elliptic to ovate with three prominent veins and finely toothed margins, finely hairy with short petioles, and joined by a ridge across the stem.

The flowers occur in small crowded bunches of 2-8 inflorescences at nodes and tips throughout the upper third of the plant; each inflorescence consists of several erect bracts 3-5 mm long surrounding 5-6 marginal ray florets and 10-20 central disc florets, each 3-4 mm long with a yellow petal. 

The dark brown to blackish (occasionally paler) seeds are dimorphic. Ray floret seeds are flattened, oblong, 3-5 mm long, with upwardly-pointing teeth along the paler marginal wing. Disc floret seeds are thickened, elongate, 3-4 mm long, with 2-4 stiff bristles at the apex. Both types of seed produce identical individuals, which in turn produce both types of seed.

The seedlings have epigeal germination. The hypocotyl is 8-19 mm long, often purplish, and hairless. The cotyledons are elliptic, 6-8 mm long, often reddish or purplish in colour and shortly stalked. The paired juvenile leaves are similar to the adult leaves but smaller.