Monographs Details: Xanthium
Authority: Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Description:Genus Description - Heads small, unisexual; staminate heads uppermost, many-fld, with poorly developed or no invol, the receptacle short, cylindric, chaffy, the filaments monadelphous, the pistil composed mainly of the undivided style; invol of the pistillate heads completely enclosing the 2 fls, forming a conspicuous 2-chambered bur with hooked prickles; pistillate fls lacking a cor, and with the styles exsert from the invol; achenes thick, solitary in the chambers of the bur; pappus none; coarse, taprooted, annual weeds with alternate lvs and solitary or clustered axillary and terminal heads. 3, originally New World.