Currently, this genus of moncotyledons i.e. plants with separate male and female flowers on the same plant, is said to consist of just two species. They are native to parts of North America and Asia

The name comes from Greek meaning "pupil" since Acorus was once used as a medicine for eye troubles. Its roots produce the sweet scented substance called calamus often used in making cosmetics. They are rhizomatous perennials often found in marshes, meadows and water side sites.

This genus was once thought to be part of the genus, Arum.