Cirsium arvense (Perennial Thistle) is a widespread and common weed of agricultural areas. In drier parts of its range it tends to occur in the wetter sites. The plant is an erect herb up to about 1m tall. The stems are not winged (as in Carduus). The leaves are dark green above (though usually with a few cobwebby hairs), white with hairs below, and with stiff spines. The heads are about 1-1.5 cm wide and have pale mauve flowers.