Any of about 75 species of low-growing plants, with corms, that make up the genus Crocus (iris family), native to the Alps, southern Europe, and the Mediterranean and widely grown for their cuplike blooms in early spring or fall. The spring-flowering sorts have a floral tube so long that the ovary is belowground, sheltered from climatic changes. Saffron comes from C. sativus of western Asia. The alpine C. vernus is the chief ancestor of the common garden crocus. Dutch yellow crocus (C. flavus) and C. biflorus are popular spring-flowering species.