Black mustard is an upright annual native to the cooler parts of North Africa, temperate Europe and parts of Asia, close enough to cabbage and turnip to share their tribe. It reaches about 1.2 metres, with large stalked leaves that are hairy or bristly at the base, four-petalled yellow flowers in summer and beaked pods of small seeds, dark brown to black, which give the plant its Latin epithet and are the reason it is grown. Carried as a crop to North America's western seaboard, it now runs wild there as an invasive, and Kynes notes that it is reckoned a noxious weed in some places. Columella wrote of it in the first century, and Grieve records that Greek physicians credited its discovery to Aesculapius; the word mustard comes from must, new grape juice, made fiery with the ground seed. It is often taken for the seed of the Gospel parable. Kynes traces it to Sumerian and Sanskrit texts of about 3000 BCE, tells of English brownies grinding the seed by night, and of seed strewn over thresholds in the American South to stop witches, who had to pick up every grain. Cunningham carries the seed in a red sachet against colds and to sharpen the mind, sprinkles or buries it at the door to keep supernatural beings out, and has women eat it for fertility. Culpeper made it an herb of Mars, with a share for Aries.