Arctium lappa

Arctium lappa, commonly called greater burdock, gobō (牛蒡/ゴボウ), edible burdock, lappa, beggar's buttons, thorny burr, or happy major is a Eurasian species of plants in the family Asteraceae.

It has become an invasive weed of high-nitrogen soils in North America, Australia, and other regions, but is cultivated for its vegetable root.

Greater burdock is a biennial plant, rather tall, reaching as much as 3 metres (10 feet). The fleshy taproot can grow up to 1 m (3+1⁄2 ft) long and 2 centimetres (3⁄4 in) across. It has large, alternating, wavy-edged cordiform leaves that have a long petiole and are pubescent on the underside.

The flowers are purple and grouped in globular capitula, united in clusters. They appear in mid-summer, from July to September. The capitula are surrounded by an involucre made out of many bracts, each curving to form a hook, allowing the mature fruits to be carried long distances. The fruits are long, compressed achenes with short pappus hairs.

Burdock roots contain mucilage, sulfurous acetylene compounds, polyacetylenes and bitter guaianolide-type constituents.^{[citation needed]} Seeds contain arctigenin, arctiin, and butyrolactone lignans.

The burdock could be confused with rhubarb, the leaves of which are toxic.

Arctium lappa was named and described by the Swedish botanist Carl Linnaeus in 1753. Its type specimen was collected from a cultivated waste area in Europe ("habitat in Europae cultis ruderatis").

This species is native to the temperate regions of the Old World, from Scandinavia to the Mediterranean, and from the British Isles through Russia, and the Middle East to India, China, Taiwan and Japan.