Summer to winter annual, similar to C. foliosum, but a ± prostrate herb, often without a distinct main stem, basal branches to 50 cm long, secondary branches few. Petiole of basal leaves to 4 cm, blade to 2.2 x 1.4 cm, triangular, dentate. Cauline leaves triangular, hastate and dentate or middle-lobe entire, especially on bracts, lobes and teeth mostly reflexed, base short attenuate to subcordate, apex acute. Glomerules 4-7 mm in diameter. Perianth segments 3, usually becoming red and succulent in fruit. Seeds 0.8-1.15 mm, ovoid (length:width ratio 1.15-1.30), margin obtuse to truncate, mostly not grooved.