Tribulus terrestris, L.

1. T. terrestris L. View in CoL , Sp. Pl. 387 (1753) View Cited Treatment .

Pubescent, procumbent annual 10-60 cm. Stems simple or freely branched. Leaves opposite, often unequal, paripinnate; pinnae 5-8 pairs, elliptical or oblong-lanceolate. Flowers 4-5 mm; petals yellow. Fruit of 5 stellately arranged, hard, rugose carpels which are keeled and tuberculate on the back, and with 2 or more stout spines on the sides. Dry open habitats, often as a weed. S. Europe, extending locally northwards to N.W. France, S.E. Czechoslovakia and E.C. Russia. Al Au BI Bu Co Cr Cz G a G r Hs Hu It Ju Lu Rm Rs (C, W, K, E) Sa Si Tu.

Varies from green and rather sparsely appressed-pubescent to almost silvery-tomentose.

Two subspecies, based on the degree of hairiness and development of spines on the fruit, are sometimes recognized. These do not appear to have any discrete patterns o f geographical distribution and are therefore best regarded as varieties.