Erect annual herb to c. 20 cm high (often much less), glabrous; stems simple or several from base, but not branched between base and the compact, often reddish inflorescence, usually with 3 terminal fertile branches which are further branched and forked. Cauline leaves alternate, sessile, usually loosely appressed to stem and overlapping, linear, oblong or very narrow-ovate, mostly 5–10 mm long, c. 1 mm wide, apex obtuse to acute, often shortly apiculate, base cuneate, margins entire; leaves/bracts on fertile branches opposite, ovate-lanceolate, those immediately subtending cyathia shorter and broader (to 2 mm wide) than cauline leaves. Cyathia solitary in paired bracts; peduncles to c. 0.5 mm long; involucre conical, c. 1 mm long; glands lunate, to c. 0.8 mm long, with 2 filiform white or reddish horn-like appendages c. 0.5 mm long; female flowers with styles shortly bifid. Capsule subglobose, c. 2 mm diam., weakly 3-lobed, smooth; seeds flattened-ellipsoid, c.1.5 mm long, grey, with conspicuous, often white tubercles; caruncle cap-like, fleshy, whitish, caducous. Flowers Nov., Dec. (2 records).
VVP. Known only from degraded native grassland in Thomastown, a northern Melbourne suburb, but there locally abundant.
A 1949 specimen from Melbourne University grounds, labelled Euphorbia exigua may be that species but differs from the form described in its more spreading and more branched habit, longer internodes, and broader leaves with truncate, 3-pointed apices. The distinctive seeds and horned, lunate glands are like those of E. exigua and a satisfactory alternative identification has yet to be found. It may represent a locally extinct form of the species from an earlier introduction.
