Tribulus terrestris

Tribulus terrestris is an annual herb native to the Mediterranean. It is adapted to thrive in dry climate locations in which few other plants can survive.

It is easily identified by its yellow flowers and narrow hairy leaves.  It propagates by seed.

The stems radiate from the crown to a diameter of about 10 cm to over 1m often branching.  They usually form flat patches on the ground though they may grow more upwards in shady areas or among taller plants.

The flowers are 4–10 mm wide, with five lemon-yellow petals, five sepals and ten stamens. 

After the flower blooms, a fruit develops that easily falls apart into five burs.  The burs are hard and bear two to four sharp spines 10 mm long and 4–6 mm broad point-to-point. 

It is known as a noxious weed because of its small woody fruit – the bur – having long sharp and strong spines which easily penetrate surfaces, such as bare feet or thin shoes of crop workers and other pedestrians, the rubber of bicycle tires, and the mouths and skin of grazing animals.