The Arum family is quite small in Finland, with 4 genera and 6 species. This monocotyledonous family used to include sweet flag, but it was moved into its own Acoraceae family. At the same time, however, the Arum family received 2 genera that are common in Finland, duckweeds (Lemna and Spirodela). Worldwide the Arum family is comprised of a total of over 100 genera and 3,000 species. Genus Calla, however, has only one member both in Finland and worldwide.