Gymnocoronis spilanthoides(D. Don) DC.

Potential aquatic weed for North America widespread in aquarium trade

IDENTITY
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Name: Gymnocoronis spilanthoides (D. Don) DC.
Taxonomic Position:
Metaphyta: Magnoliophyta: Magnoliopsida: Asterales: Asteraceae
Common Names: Spade-leaf plant (aquarium trade); Senegal tea; temple plant; costata (Australia)

Significance:
This year, the Weed Science Society of America (WSSA) identified this emergent perennial herb as one of sixteen weeds not yet present in the US but posing the greatest potential threat to its ecosystems. Native to tropical and subtropical regions of America from Mexico to Argentina, Senegal tea is introduced to Australia and New Zealand, where it has quickly become a pest of aquatic habitats. Gymnocoronis spilanthoides is also a popular aquarium plant and is widely available from North American and international suppliers over the internet.

Issues of Concern: The spade-leaf plant's presence in Mexico, and its prominent place in the plant trade, is of particular concern to vulnerable aquatic habitats in North America. Gymnocoronis spilanthoides is found in still or slow-moving water, as well as wet marshy soils. It can form mats of tangled, vegetative stems that extend far from the stream banks along which it grows, impeding water flow, navigation, and recreation. In fertile situations, G. spilanthoides can exceed a growth rate of 15 cm per week, and is known in the aquarium trade as being beneficial for controlling algae because of its voracious appetite for nutrients.

Pathways: This weed is readily available over the internet as an aquarium plant.

Distribution:
Australia; India; North America (Mexico); South America (Argentina, Brazil, Paraguay, Uruguay)

Quarantines: Australia placed this species on its noxious weed list in 2000.

Detection Strategies
The spade-leaf plant has numerous white florets; the stems are pale green, erect at first but becoming prostrate, and there is much scrambling and branching at the nodes.

OTHER INFORMATION:
References:
Holm, L.G., Pancho, J.V., Herberger, J.P. and Plucknett, D.L. 1979. A Geographical Atlas of World Weeds. New York, USA: John Wiley and Sons. 391 pp.
Parsons, W.T. and Cuthbertson, E.G. 1992. Noxious weeds of Australia. Inkata Press, Melbourne/Sydney. Pp. 575-577.

Useful Links:
http://www.hear.org/pier/gyspi.htm
http://www.boprc.govt.nz/www/green/weed104.htm

Warning: The information in this archived item was not confirmed with the appropriate National Plant Protection Organization and is provided solely for informational purposes. Please use this information with caution.