Tribulus terrestris L.
Diagnostic description:
A pubescent branching annual, with decumbent stems up to 80 cm long. Leaves paripinnate with 2 to 8 pairs of ovate to oblong leaflets which are from 1 to 1.5 cm long. Flowers yellow, about 1 cm across, solitary in the leaf axils. Fruit with 5 lobes arranged roughly in the shape of a Maltese cross, each with 4 stout spines, two short and two long.
Distribution:
Local: Common in Gibraltar. Found mainly in the North Front area, especially on North Front Cemetery, with scattered plants elsewhere. Grows on sandy soil and waste ground.
Global: Found in the Mediterranean region, south-east Europe, and the Canary Islands.
Ecology:
Flowers between (May) June and September (October).