Etymology: Xanthium: from a Greek word meaning "yellow"
Plants: erect, annual, 1'-4' tall forb with rough stems
Leaves: lance-like, tapering to base, silvery beneath, with 1/3" - 3/4" yellow spine in the axils
Flowers: head green; inflorescence of 1 to a few heads in leaf axils; blooms July-Oct.
Fruits: thick dry seeds, clustered in a 1/3" cylindrical bur with thin hooked prickles
Habitat: disturbed sites
Conservation Status: Introduced - adventive
Flora of North America: Flora of North America Floristic Rating: Wetland Indicator = FACU USDA Plants Database: Federal Distribution and detailed information including photos USDA Agricultural Research Service (ARS): Images of seeds, fruits, embryos, etc. Southwest School of Botanical Medicine: Britton & Brown Illustrated Flora - 2nd Edition (1913) "An Illustrated Flora of the Northern United States and Canada"