Emex
2 species naturalized Aust.; all states and territories except Tas.
*Emex australis
Glabrous, monoecious, prostrate annual. Leaves ovate, truncate or cordate at the base, mostly 3–6 cm long, on long petioles. Flowers unisexual, axillary, in whorl-like clusters. Female perianth enlarged and hardened at fruiting stage, 7–9 mm long, with a triangular tube and 6 lobes; outer lobes terminating in a rigid spreading spine; inner lobes smaller, ovate, closing over the fruit. Widespread. Weed of waste ground and pastures. Introd. from S. Africa. Spiny Emex or Prickly Jacks