Gymnocoronis spilanthoides DC., Asteraceae

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Present on Pacific Islands?  no

Primarily a threat at high elevations?  no

Risk assessment results:  Reject, score: 7 (Go to the risk assessment)

Common name(s): [more details]

English: Senegal tea, temple plant

Habit:  herb

Description:  "A freshwater or marsh-growing emergent perennial herb which forms rounded bushes or, extending from the banks, mats of tangled stems, reproducing vegetatively and by seed.  Stems:  Pale green, erect at first but becoming prostrate, scrambling and branching at the nodes, 1 to 1.5 m long, 5 to 10 mm diameter at first increasing to 1 to 2 cm with age; internodes hollow, inflated and buoyant.  Leaves dark green; opposite, ovate to lanceolate, 5 to 20 cm long, 2.5 to 5 cm wide, on shortish stalks, margins serrate and slightly wavy.  Flowers:  Florets, whitish, numerous, grouped into terminal heads 1.5 to 2 cm diameter, subtended by a single row of green involucral bracts.  Seed yellow-brown, 5 mm diameter, ribbed, without a crown or pappus.  Root:  Numerous, finely fibrous adventitious roots developing from the nodes"  (Parsons and Cuthbertson, 1992; pp. 285-287).

Habitat/ecology:  "A prostrate, aquatic perennial that grows over the surface of slow-moving or stationary water bodies.  It can form dense, floating mats and is usually rooted in damp soil.  It can sometimes form rounded bushes up to 1 m tall, but more commonly forms a dense mat with floating, hollow stems several meters in length.  Roots can be produced from regularly spaced nodes along the stem, enabling the plant to regrow from stem fragments dislodged by floodwater or other disturbance" (Csurhes & Edwards, 1998; pp. 39-40).

Propagation:  Seed or stem fragments carried by water.  Commonly introduced and sold as an aquarium plant and thus spread by humans.

Native range:  Tropical and sub-tropical South America from Mexico to Argentina.

Presence:

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia Australia (continental)	New South Wales	introduced invasive cultivated	Csurhes, S./Edwards, R. (1998) (pp. 39-40)
Australia Australia (continental)	Queensland	introduced invasive cultivated	Csurhes, S./Edwards, R. (1998) (pp. 39-40)
Mexico Mexico	Mexico (United Mexican States)	native	Weber, Ewald (2003) (p. 185)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Owen, S. J. (1997)
Perú Perú	Perú (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)

Comments:  A problem species in Australia, New Zealand and India.

Control: 

Physical:  "Rake the plant material from the water, spread it thinly over a suitable surface to dry and then rake into heaps and burn.  Repeat as required"  (Parsons and Cuthbertson, 1992; pp. 285-287).  "Dig out small sites (all year round): Dispose of plant material at refuse transfer station, or dry out and burn.

Chemical: "1. Weed wipe (spring-summer): glyphosate (500ml/L + penetrant).  2. Spray (sprig-summer): glyphosate (20ml/L)"  (Weedbusters New Zealand).

Additional information:
Information from the Global Invasive Species Database.
Fact sheet from the Bay of Plenty Regional Council, New Zealand.
Fact sheet from the Government of Queensland, Australia (PDF format).
Weed Management Guide from the Government of Australia. (PDF format).
Photos and additional information at the Environment Bay of Plenty, New Zealand, web site of the Bay of Plenty Regional Council (see thumbnails above).
Information sheet from Weedbusters New Zealand.

Additional online information about Gymnocoronis spilanthoides is available from the Hawaiian Ecosystems at Risk project (HEAR).

Information about Gymnocoronis spilanthoides as a weed (worldwide references) may be available from the Global Compendium of Weeds (GCW).

Taxonomic information about Gymnocoronis spilanthoides may be available from the Germplasm Resources Information Network (GRIN).

References:

Csurhes, S./Edwards, R. 1998. Potential environmental weeds in Australia: Candidate species for preventative control. Canberra, Australia. Biodiversity Group, Environment Australia. 208 pp.

Owen, S. J. 1997. Ecological weeds on conservation land in New Zealand: A database. Working draft. Wellington, New Zealand. Department of Conservation.

Parsons, W. T./Cuthbertson, E. G. 1992. Noxious weeds of Australia. Inkata Press, Melbourne/Sydney. 692 pp.

Timmins, S. M./Mackenzie, I. W. 1995. Weeds in New Zealand protected natural areas database. Wellington, New Zealand. Department of Conservation, , Technical Series No. 8. 287 pp.

U.S. Dept. Agr., Agr. Res. Serv. 2011. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.

Weber, Ewald. 2003. Invasive plants of the World. CABI Publishing, CAB International, Wallingford, UK. 548 pp.