Iva annua, the annual marsh elder
Description
Iva annua is an annual herb up to 150 cm (5 feet) 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.
[ Flora of North America, Iva annua Linnaeus, 1753. ] Marshelder has a unique odor when the leaves or pollen are touched, but this odor is not present in winnowed seed.
Cultivated varieties of Marshelder (var. macrocarpa) bred by Native Americans possessed seeds 6-9mm in length; whereas wild-type Marshelder has seeds 3 mm in length on average (not exceeding 4.5 mm). [Weiland, A. W., & Gremillion, K. J. (2018). Patterns of Variation in the Seed Morphology of Iva annua var. Macrocarpa, an Extinct North American Domesticate. Ethnobiology Letters, 9(2), 75–89.
]
Distribution
It is native to northeastern Mexico (
Tamaulipas) 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.
[ Biota of North America Program 2014 county distribution map]
Conservation
NatureServe evaluated
Iva annua in 1998 as globally secure, G5.
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 unique odor. Probably for these reasons it was abandoned after more pleasant alternatives (such as maize) were available and, by the time Europeans arrived in the Americas, had disappeared as a crop.
See also
External links
