Plants villous annuals. Leaves stipulate; stipules up to 1 mm long; blades 1-2 cm long, with 4-6 pairs of leaflets; leaflets ovate-oblong, 3-4 mm and about 2.5 mm wide. Flowers pedicillate; pedicels 2-5 mm long, elongating to up to 10 mm in fruit sepals linear-lanceolate, 1-2 mm long; petals yellow, 2-4 mm long; stamens 5(-8); filaments 1-1.5 mm long; gynoecia: styles about 0,5 mm long; stigmas pyramidal, about 0,1 mm long. Fruits disc-shaped. 4-6 mm across excluding the spines; mericarps 2-3 mm long, 1-2 mm across, with 2 median and, usually, 2 basal spines 1.5-3 mm long.
Tribulus parvispinus grows on coastal plains in limestone alluvial silt at about 10 mm elevation. In 1993, it was known only from the Red Sea coast of the N3 region.
Mary E. Barkworth
Habit:hairy, prostrate annual.
Leaves: opposite, even-pinnate, 1-2 cm long.
Flowers: with 5 separate yellow petals 2-4 mm long and styles about 0.5 mm long.
Fruits: discs of 5 mericarps, each mericarp 2-3 mm long and usually 4, sometimes 2, spines.
Tribulus parvispinus is a coastal species, growing in alluvial silt derived from limestone at elvations of up to 10 m. It differs from , but Tribulus terrestris in having shorter leaves, smaller flowers, and smaller mericarps but it approaches T. terrestris in each feature. The biggest difference is in its restriction to coastal habitats.