Iva annua L. - Annual Marshelder

Iva annua plant

Family - Asteraceae

Stems - No info yet.

Iva annua stem

Leaves - No info yet.

Iva annua leaves

Inflorescence - No info yet.

Iva annua inflorescence

Involucre - No info yet.

Ray flowers - Absent.

Disk flowers - No info yet.

Iva annua flowers

Flowering - July - October.

Habitat - Alluvial soils, roadsides, railroads.

Origin - Native to U.S.

Other info. - This weedy species can be found throughout most of Missouri but is apparently absent from the northwest corner of the state as well as the central Ozark region. The plant can be identified by its opposite, petiolate, ovate-triangular leaves, attenuate bracts of the inflorescence, and pubescent stems. This species produces copious amounts of air-borne pollen which is a major cause of hay fever in the fall.

Photographs taken off Macon County Road 43, Macon County, AL., 10-9-04.


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