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

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

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

Common name(s): [more details]

Chinese: gui yuan ju

English: Brazilian cress, Para cress, para-cress, toothache plant

French: cresson du Brazil, cresson du Para

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).

Description from the Flora of China online.

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:  "Originating in South America and known only from cultivation, but escaped in weedy habitats in many areas"  (Flora of China online).

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
Papua New Guinea Bismarck Archipelago	Bismarck Archipelago		Peekel, P. G. [translated by E. E. Henty] (1984) (p. 563) Widespread, in plantations, gardens, waysides and farms; not abundant.

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
China China	China (People's Republic of)	introduced cultivated	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013)
Taiwan Taiwan Island	Taiwan Island	introduced cultivated	Ching-I Peng, ed. (2013)

Control:  If you know of control methods for Acmella oleracea, please let us know.