Conopodium majus

Conopodium majus is a perennial herbaceous flowering plant in the celery family, Apiaceae. Its underground part resembles a chestnut and is sometimes eaten as a wild or cultivated root vegetable. The plant has many English names (many of them shared with Bunium bulbocastanum, a related plant with similar appearance and uses) variously including kippernut, cipernut, arnut, jarnut, hawknut, earth chestnut, groundnut, and earthnut. From its popularity with pigs come the names pignut, hognut, and more indirectly Saint Anthony's nut, for Anthony the Great or Anthony of Padua, both patron saints of swineherds. (Other plants sharing these names include groundnut, earthnut, and hognut.)...read more on Wikipedia.