caltrop

n 1: tropical annual procumbent poisonous subshrub having fruit

that splits into five spiny nutlets; serious pasture

weed [syn: {devil's weed}, {Tribulus terestris}]

2: a plant of the genus Trapa bearing spiny four-pronged edible

nutlike fruits [syn: {water chestnut}, {water chestnut

plant}]

3: Mediterannean annual or biennial herb having pinkish to

purple flowers surrounded by spine-tipped scales;

naturalized in America [syn: {star-thistle}, {Centauria

calcitrapa}]