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Marshelder, Giant Sumpweed

Cyclachaena xanthifolia (Nutt.) Fresen.

(formerly Iva xanthifolia Nutt.)

Asteraceae (Sunflower Family)

▲▼ seedlings 

 

▲▼ seedlings

▲▼ young plants

 

▲▼ young plants 

 

 

▲▼ stems and leaves, showing opposite leaf arrangement and stem and petiole hairs 

 

▲ maturing plants

 

▲▼ leaf characteristics

 

▲▼ leaf characteristics 

 

▲▼ mature, flowering plants 

▲▼ mature, flowering plants

 

 

▲▼ flowers/inflorescences 

▲▼ flowers/inflorescences 

 

▲▼ flowers/inflorescences 

 

▲▼ flowers/inflorescences 

 

 

Cyclchaena xanthifolia (Nutt.) Fresen. (formerly Iva xanthifolia Nutt.) Giant Sumpweed, Marshelder:  (Bayer Code:  IVAXA; US Code IVXA)

·         U.S. native summer annual weed growing 3-8 feet tall with slightly-hairy, ridged stems; usually not much branching on stems until upper portions

·         Leaves are opposite, large, triangular to rounded-triangular with toothed margins and 3 main veins emerging from the long petiole (palmate veining)

          o   Seedlings may have leaves that are more deeply 3-lobed in some locations

·         Flowers small, greenish in terminal panicles at tips of stems and from axils of upper stem leaves

·         Found in cultivated crops, non-crop areas, particularly in wetter soils

·         More common in northern Midwest and along Missouri & Mississippi rivers

·         Younger plants may appear similar to velvetleaf (Abutilon theophrasti) or annual sunflower (Helianthus annuus), but marshelder has small, green flowers, compared to the more showy flowers of velvetleaf and sunflower; also, velvetleaf has alternate, very soft fuzzy (velvety) leaves

 

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