Basal leaves withered at time of flowering; lowest stem leaves ± 7–9 × 3–6 cm., lamina broadly deltoid-ovate, ± bipinnate with 2–3 pairs of pinnae, basal pair with petiolules up to ± 1.5 cm. long, pinnae rather irregularly divided into linear, glabrous, rather bluntly mucronate segments up to ± 1.8 cm. long and ± 0.5–1.5(–2) mm. wide, flat with ± revolute margins, not dentate; petioles ± 2.5–4 cm. including the tapering, 4–10 mm., ribbed sheath; upper stem leaves becoming smaller, with shorter petioles and finally sessile, and segments narrower but otherwise very similar; uppermost leaves also much divided but very small.
Umbels numerous, with ± 3–10 rays 6–32 mm. long, glabrous or minutely scabrid; involucre absent or of a single linear bract up to ± 6 mm. long; partial umbels ± 11–18-flowered; pedicels 1–3 mm., glabrous or with bristly hairs; involucel of 3–6 subulate, 2–4 mm. bracteoles with scabrid margins; peduncles ± 2–8 cm., glabrous.
Annual herb, ± 15–70 cm. tall, much branched from near the base upwards except in depauperate plants, with long divergent branches; stem and branches slender, terete, striate, glabrous.
Petals white, obcordate with abroad, deep notch, ± 0.75 mm., shortly white hairy; anthers yellow or orange.
Fruit broadly ovate, ± 2 × 2 mm., white pilose or only verrucose, ribs not very prominent though more so in the verrucose form; stylopodia bluntly conical; styles slender, deflexed along the sides of the fruit, 2–3 times as long as the stylopodium.