Huacatay (Tagetes minuta), often called Peruvian black mint, is a tall, intensely aromatic Andean herb of the marigold genus whose feathery, finely divided leaves carry a startling green scent — basil, mint, citrus, tarragon and a resinous marigold edge colliding at once. Native to the temperate grasslands and highlands of southern South America, it is the soul of Peruvian ocopa sauce and perfumes stews, chilli pastes and the country's green table sauces.