Xanthium
(the old Greek name used by Dioscorides, from xanthos, yellow; the plants were formerly used by the Greeks for dyeing hair). Cockle Bur; Clot Bur. ORD. Compositae. A genus consisting of about four species of hardy, annual herbs, dispersed over warm and temperate regions. Flower-heads solitary or glomerate at the axils, unisexual. Leaves alternate, lobed or toothed. The species are of no horticultural value. X. spinosum (Bathurst Bur; Spiny Clot-Bur) and X. strumarium (Ditch or Louse Bur; Small Burdock) are casual weeds in Britain.