The common name of cotton thistle derives from the cotton-like hairs on the leaves. Other names include Scots thistle or Scottish thistle, heraldic thistle and woolly thistle. The name Scots thistle comes from the flower used as the national emblem of Scotland. Despite its name, it has nothing to do with the actual thistle that is used as the emblem of Scotland, which is the "Cirsium vulgare". It is grown as an ornamental plant for its bold foliage and large flowers. It has been used to treat cancers and ulcers and to diminish discharges of mucous membranes. A recent study of a crude extract from the leaves of the plant proved the activity against glioblastoma cell line, a very malignant brain tumor. The receptacle was eaten in earlier times like an artichoke. The cottony hairs on the stem have been occasionally collected to stuff pillows. Oil from the seeds has been used for burning and cooking. Thistles produce abundant nectar for pollinators and provide seeds and floss for birds such as the goldfinch. Large-flowered tall thistles in particular provide considerable nectar. In the late 19th century, it was introduced to temperate regions of North America, South America, and Australia as an ornamental plant, and is now considered a major agricultural and wildland noxious weed. It has been recorded from nearly 50 countries. It is difficult to eradicate because of its drought resistance. It can spread rapidly and eventually dense stands prohibit foraging by livestock. Infestations of cotton thistle often start in disturbed areas such as roadways, campsites, burned areas, and ditch banks. The weed adapts best to areas along rivers and streams, but can be a serious problem in pastures, grain fields and range areas. A single plant is imposing enough, but an entire colony can ruin a pasture or destroy a park or campsite, sometimes forming tall, dense, impenetrable stands. This issue is often amplified by the prolific thorns found on this species. Besides creating an impenetrable barrier to humans and animals, the plant nearly eliminates forage use by livestock and some mammal species such as deer and elk. Known infestations include most of the Pacific Northwest along with Utah, Colorado, New Mexico, Wyoming, Nebraska, and South Dakota. On western rangeland, infestations directly result in significant economic losses for ranchers. It is also widespread in Australia and New Zealand. In Australia it commonly hybridises with the related invasive "Onopordum illyricum".