The species name of cymopterus purpureus
refers to the thick stems, which are deep purple around the base, becoming lighter towards the tip. Flowers are golden yellow or greenish yellow (withering to purple-brown); a flattish umbel of small clusters of tiny flowers supported by pointed bracts, joined to the main stem by short, ridged petioles. The yellow-tipped stamens protrude a little way above the flower center, which is surrounded by five petals. When in full bloom, the flower stalks tend to sag down to the ground, and the leaf branches also grow sideways rather than vertically. Leaflets are noticeably pointed at their tips.