22 gen., Aust. & S. Africa

Tribulus L.

12 species in Aust. (9 endemic); all states and territories except Tas.

Prostrate herb. Leaves opposite, pinnate-compound with 8–16 oblong leaflets. Flowers regular, bisexual, solitary. Petals yellow, 5, induplicate-valvate. Stamens 10, hypogynous. Ovary 5-locular, with axile placentas, superior, surrounded at the base by a sinuate disc in the gland at the base of each stamen. Fruit a muricate spiny schizocarp.