Acorales is a basal order or flowering plants and is a division of the Phylum Angiosperm, Class Monocotyledon. The order Acorales has one family Acoraceae and one Genes Acorus. However, the genus Acorus has three species.

The genus Acorus contains monocot flowering plants with common names which include calamus and sweet flag. This genus is found in North America, Asia and has been cultivated in Europe since ancient times.

The plant, sweet flag is a herbaceous perennial, 6 to 7 feet tall (2 m). The leaves of the Acorus calamus resemble those of the iris family. Sweet flag consists of tufts of basal leaves that rise from a spreading rhizome. The leaves are erect yellowish-brown, radical, with pink sheathing at their bases, sword-shaped, flat and narrow, tapering into a long, acute point, and have parallel veins.

The leaves have smooth edges, which can be wavy or crimped. The sweet flag can be distinguished from iris and other similar plants by the crimped edges of the leaves, the fragrant odor it emits when crushed. Only those plants which grow in water bear flowers.

Habitats include edges of small lakes, ponds and rivers, marshes, swamps, and other wetlands.[

Sweet flag grows in India, Nepal, central Asia, southern Russia and Siberia, Europe and North America.