Acmella oleracea (L.) R.K.Jansen, Asteraceae

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Present on Pacific Islands?  yes

Threat only at high elevations?  no

Other Latin names:  Spilanthes oleracea L., Spilanthes acmella sensu various authors.

Common name(s): [more details]

English: Para cress, para-cress, toothache plant

Habit:  herb

Description:  "Plants annual.  Stems decumbent to usually erect, not rooting at nodes, green to red, 2.5-7.5 mm in diameter, glabrous.  Petioles 20-64 mm long, glabrous to very sparsely pilose, narrowly winged.  Leaf blades 53-106 mm long, 40-79 mm wide, broadly ovate to deltate, base truncate to short attenuate, apex short acuminate to usually acute, usually glabrous above and below, margin dentate.  Peduncles 3.5-12.5 cm long, 2-3.8 mm in diameter, glabrous to very sparsely pilose.  Heads discoid, 10.5-23.5 mm high, 11-17 mm in diameter.  Receptacle 8.3-21.5 mm high, 3.5-8.5 mm in diameter, occasionally 2 per head, apex acute.  Phyllaries 15-18, triseriate, herbaceous, margin entire to sinuate, sparsely ciliate; outer series 5-6, 5.8-7.3 mm long, 2.1-2.8 mm wide, usually narrowly ovate to lanceolate or sometimes ovate, apex acute; middle series 5-6, 5.8-7.3 mm long, 2.1-2.8 mm wide, lanceolate, apex acute; inner series 5-6, 5.5-6.5 mm long, 1.3-2 mm wide, lanceolate, apex acute.  Pales 5.3-6.2 mm long, 1-1.2 mm wide, apex acute, stramineous or often with a purple-red tinge.  Disc florets 400-620; corollas 2.7-3.3 mm long, yellow, 5-merous; tube 0.5-0.7 mm long, 0.2-0.4 mm in diameter; throat 2.2-2.6 mm long, 0.5-1 mm in diameter; lobes 0.3-0.6 mm long, 0.2-0.4 mm wide; stamens 1.4-1.7 mm long, anthers black; style 1.8-2.5 mm long, the branches 0.6-0.8 mm long; achenes 2-2.5 mm long, 0.9-1.1 mm wide, moderately to densely ciliate with straight-tipped hairs; lacking a cork-like margin and shoulders; pappus of 2 sub- or unequal bristles, the longer bristle 0.5-1.5 mm long, the shorter 0.3-1.3 mm long" (Jansen, 1985; pp. 65-66).

Habitat/ecology:  "Known only from cultivation and found escaped in weedy habitats. It is grown primarily in botanical and herb gardens for medicinal and ornamental purposes" (Jansen, 1985; pp. 65-66).

Propagation:  Seed

Native range:  Only cultivated, probable origin Peru (GRIN).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
New Caledonia New Caledonia	New Caledonia Islands	introduced invasive	Gargominy, Oliver/Bouchet, Philipe/Pascal, Michel/Jaffre, Tanguy/Tourneu, Jean-Christophe (1996) (p. 379) Rudérale, nombreuses localités
New Caledonia New Caledonia Archipelago	Île Grande Terre	introduced cultivated	MacKee, H. S. (1994) (p. 38) Voucher cited: MacKee 38456

Additional information:  Additional online information about Acmella oleracea is available from the Hawaiian Ecosystems at Risk project (HEAR).

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

References:

Gargominy, Oliver/Bouchet, Philipe/Pascal, Michel/Jaffre, Tanguy/Tourneu, Jean-Christophe. 1996. Conséquences des introductions d'espèces animales et végétales sur la biodiversité en Nouvelle-Calédonie. Rev. Ecol. (Terre Vie) 51:375-401.

Jansen, Robert K. 1985. The systematics of Acmella (Asteraceae-Heliantheae). Sys. Bot. Monogr. 8:1-115.

MacKee, H. S. 1994. Catalogue des plantes introduites et cultivées en Nouvelle-Calédonie. Muséum National d'Histoire Naturelle, Paris, 164 p.

U.S. Dept. Agr., Agr. Res. Serv. 2007. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.