E-Flora BC: Electronic Atlas of the Flora of British Columbia

Cyclachaena xanthifolia (Nutt.) Fresen
marsh-elder (giant sumpweed; marsh elder)
Asteraceae (Aster family)

Introduction to Vascular Plants

© Curtis Bjork  Email the photographer   (Photo ID #21983)

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Distribution of Cyclachaena xanthifolia
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Marsh elder is an introduced annual weed species in the Daisy Family (Asteraceae) that originates in the western United States. It is found in British Columbia in moist to mesic disturbed sites (abandoned fields, bottomlands, flood plains, stream banks) (Strother 2012). Flowers are present from summer (July/August) to fall, and occur in panicled spikes (Strother 2012). They are green to white in colour.

Species Information

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Annual herb from a taproot; stems erect, simple, glabrous below, fine-hairy and glandular above, up to 2 m tall.
Basal leaves soon deciduous; stem leaves long-stalked, broadly egg-shaped or heart-shaped, 5-20 cm long, 2.5-20 cm wide, green above, whitish short-hairy below, at least when young, coarsely toothed or doubly-toothed.
Heads disciform, numerous in a large, terminal panicle, not subtended by the leaves; involucres 1.5-3 mm tall; the 5 outer involucral bracts larger than the 5 inner membranous bracts which partly enfold the achenes; female flowers obsolete or nearly so.
Achenes egg-shaped, sparsely fine-hairy towards the tip, minutely pimply in lines, 1.5-2 mm long; pappus lacking.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Moist to mesic roadsides and waste places in the lowland, steppe and montane zones; infrequent throughout S BC; introduced from W US.

Source: The Illustrated Flora of British Columbia


The climate type for this species, as reported in the: "British Columbia plant species codes and selected attributes. Version 6 Database" (Meidinger et al. 2008), is not evaluated, unknown or variable.

Synonyms and Alternate Names

Iva xanthifolia Nutt.

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References