A genus of between 200–300 species of flowering plants with showy flowers.

The genus is widely distributed throughout the north temperate zone. Their habitats are considerably varied, ranging from cold and montane regions to the grassy slopes, meadowlands and riverbanks of Europe, the Middle East and northern Africa, Asia and across North America.

Irises are perennial herbs, growing from creeping rhizomes (rhizomatous irises), or, in drier climates, from bulbs (bulbous irises). They have long, erect flowering stems, which may be simple or branched, solid or hollow, and flattened or have a circular cross-section. The rhizomatous species usually have 3–10 basal, sword-shaped leaves growing in dense clumps. The bulbous species have cylindrical, basal leaves.

The inflorescences are fan-shaped and contain one or more symmetrical six-lobed flowers. The three sepals, which are spreading or droop downwards, are referred to as "falls". They expand from their narrow base, which in some of the rhizomatous irises has a "beard" (a tuft of short upright extensions growing in its midline), into a broader expanded portion ("limb"), often adorned with veining, lines or dots. The three, sometimes reduced, petals stand upright, partly behind the sepal bases.

from: Wikipedia