The common thistle is known to botanists as onopordum acanthium and to everyone else as the Scotch thistle or Scottish thistle. A relative of the sunflower family, the Scottish thistle achieved fame and standing as the national emblem of Scotland. More than 200 types of thistles exist, many viewed less gloriously than the common thistle in Scotland.The cotton thistle is a large plant, up to three meters tall and about half that in width. A biennial plant, its spiny leaves are 10 to 50 cm wide, covered with white hairs that give the plant the common name "cotton thistle." They have long, stiff spines the length of the margins. The flowers are round and range in color from pink to lavender. The thistle flowers from July to September.