Euphorbia segetalis L.

Glabrous, erect annual. Stems up to 35–(40) cm high, branched or not from base. Lvs alternate, exstipulate, sessile, entire, linear, obtuse at base, acuminate, 15–40 mm long. Terminal umbel usually 5-rayed, with often several axillary rays arising below; lvs subtending rays linear to narrowly ovate-elliptic; rays sometimes secondarily branched then forming conspicuous yellow, compound dichasia; lvs subtending ray-branches and cyathia deltate, obtuse. Glands elliptic-oblong; horns long, slender. Capsule smooth, deeply grooved, granulate on keels. Seeds rounded, with numerous irregular shallow pits, grey on ridges and brown in pits, 1.5–2 mm long.

[From: Webb et al. (1988) Flora of New Zealand. Volume 4.]