About 80 species of cormous perennials from the northern temperate zone ranging from North Africa, through the Mediterranean to the Middle East with outliers in central Europe and central Asia. The corm is of annual duration, a new one developing above the old during the growing season. Some species produce multiple corms or corm-lets, a few are stoloniferous. Propagation in the wild is usually by seed. The texture of the corm tunic is used in identification and classification. Flowers almost stemless direct from the corm, having a stalk like perianth tube surmounted by six perianth lobes (tepals). Flower colour ranges from lilac to purple, white or yellow. The styles are normally orange but sometimes scarlet and may then contribute to the aesthetic appeal. The seed pods are below ground until mature then emerge and split. Leaves, produced with or at varying intervals after the flowers, are narrow, with a central pale stripe and a keel on the underside. Leaf cross section may be of diagnostic value. Flowering period ranges from late summer to late spring. However, flowering time can be widely influenced by soil, weather, degree of protection and particular clones.
Many species and cultivars make excellent subjects for a rock garden or raised bed. Less hardy species and those requiring warmth and dryness during dormancy can be accommodated in a bulb frame or as pot plants in the alpine house. Various loam-based and peat-based composts have been successfully used and a sunny site is essential. It is important to ensure that adequate moisture is available while the roots are active and supplementary liquid feeds with high-potassium fertiliser help to ensure the development of the new corm. Vegetative propagation is easy when multiple new corms are produced. Otherwise increase is by seed sown when ripe or spring. (Height of flowers is above ground only)