Etymology: Tribulus: Latin for "three-pointed, a caltrop," the shape of which is suggested by the three-pronged fruit, and referring to the caltrop, a military weapon, an iron ball with projecting spikes
Plants: annual forb
Conservation Status: Introduced - adventive
Invasive And Exotic Species of North America: Descriptions, management issues, warnings, photos, etc. USDA Plants Database: Federal Distribution and detailed information including photos USDA Agricultural Research Service (ARS): Images of seeds, fruits, embryos, etc. Illinois Wildflowers: Wonderful photographs; detailed descriptions; color and leaf arrangement key Southwest School of Botanical Medicine: Britton & Brown Illustrated Flora - 2nd Edition (1913) "An Illustrated Flora of the Northern United States and Canada"