Iva annua Linnaeus. Sumpweed, Rough Marsh-elder. Phen: Aug-Nov. Hab: Fields, especially bottomlands, disturbed places; in the eastern and inland part of area probably introduced (by native Americans) from farther west. Dist: PA, ND, and CO south to FL, NM, and Mexico (the original distribution uncertain). Reported for MD (Longbottom, Naczi, & Knapp 2016).

Origin/Endemic status: Native

Taxonomy Comments: The so-called var. macrocarpa (Blake) R.C. Jackson, known only from archeological remains and presumed extinct, is almost certainly a cultivated form, selected for its large seeds.

Other Comments: This species was an important crop of native Americans.

Synonymy: = C, Fl7, FNA21, GrPl, GW2, Il, K3, K4, Mi, NcTx, NE, Oh3, Pa, RAB, SE1, Tn, Tx, Va, W, WH3; = Iva ciliata Willd. – F; = n/a – Tat; > Iva annua L. var. annua – K1, Jackson (1960); > Iva annua L. var. caudata (Small) R.C.Jacks. – K1, Jackson (1960); > Iva annua L. var. macrocarpa (Blake) R.C.Jacks. – K1, Jackson (1960); > Iva caudata Small – S; > Iva ciliata Willd. – S; > Iva ciliata Willd. var. ciliata – G; > Iva ciliata Willd. var. macrocarpa Blake – G

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Wetland Indicator Status:

• Atlantic and Gulf Coastal Plain: FAC
• Eastern Mountains and Piedmont: FAC
• Great Plains: FAC
• Midwest: FAC
• Northcentral & Northeast: FAC

Heliophily: 8