Annual Sumpweed

Appearance

''Iva annua'' is an annual herb up to 150 cm tall. The plant produces many small flower heads in a narrow, elongated, spike-like array, each head with 11–17 disc florets but no ray florets.

Distribution

It is native to northeastern Mexico and to the central and southern United States, primarily the Great Plains and Mississippi Valley as far north as North Dakota. There are some populations in the eastern US, but these appear to represent introductions.

Uses

''Iva annua'' was cultivated for its edible seed by Native Americans around 4,000 years ago in the central and eastern United States as part of the Eastern Agricultural Complex. It was especially important to the indigenous peoples of the Kansas City Hopewell culture in present-day Missouri and Illinois. The edible parts contain 32 percent protein and 45 percent oil.

However, like its relative ragweed, sumpweed possesses many objectionable qualities which include being a severe potential allergen and possessing a disagreeable odor. Probably for these reasons it was abandoned once more pleasant alternatives were available, and by the time Europeans arrived in the Americas, had long disappeared as a crop.