Acmella uliginosa
(marsh para cress)

Preferred Scientific Name

• Acmella uliginosa (Sw.) Cass.

Preferred Common Name

• marsh para cress

Other Scientific Names

• Calea savannarum Standl. & Steyerm
• Ceratocephalus acmella var. depauperata Kuntze
• Ceratocephalus acmella var.uliginosa (Sw.) Kuntze
• Coreopsis acmella var. uliginosa (Sw.) Baker
• Spilanthes acmella var. uliginosa (Sw.) Baker
• Spilanthes lundii DC.
• Spilanthes lundii DeCandolle
• Spilanthes uliginosa Sw.
• Spilanthes uliginosa var. discoidea Aristeg.
• Spilanthes uliginosa var. uliginosa

International Common Names

• Spanish: chimapaya; chinapaya
• Chinese: zhao sheng jin niu kou

Local Common Names

• Fiji: mbotembotekoro
• Haiti: créosote pays; herbe mal aux dents; herbe mal dents; z'herbe amal aux dents; z'herbe mal aux ents
• Lesser Antilles: bouton d'or

• Domain: Eukaryota
•     Kingdom: Plantae
•         Phylum: Spermatophyta
•             Subphylum: Angiospermae
•                 Class: Dicotyledonae
•                     Order: Asterales
•                         Family: Asteraceae
•                             Genus: Acmella
•                                 Species: Acmella uliginosa

Asteraceae is one of the largest families of flowering plants including about 1620 genera and more than 23,600 species (Stevens, 2012). Members of this family are very variable vegetatively, but may be recognized by their capitulate and involucrate inflorescences in which numerous small flowers open first on the outside and are only sometimes subtended by bracts. The rather small, single-seeded fruits usually have a plumose pappus and are frequently dispersed by wind (Stevens, 2012). The genus Acmella Rich. & Pers. includes about 30 species. The genus has very complex patterns of morphological and chromosomal variation that have caused difficulties in delimiting taxa. Most species within the genus Acmella are distributed in the tropics with matted to erect growth habits, and some have pantropical distributions (Jansen, 1985a). 

Annual, sometime perennial herb, 10-30(-50) cm tall. Stems solitary or several from base, erect to ascending or occasionally decumbent, green to purple, glabrous to moderately pilose. Petiole 0.5-1.5 cm, sparsely to moderately pilose, wingless or narrowly winged; leaf blade lanceolate, narrowly ovate to ovate, 1.3-5 × 0.3-2.5 cm, glabrous to sparsely pilose on both surfaces, base attenuate to cuneate, margin sinuate to dentate, sparsely ciliate, apex acute to acuminate. Capitula radiate, solitary or 2 or 3, terminal, ovoid, 5-8 × 4-6 mm; peduncles 1.2-3 cm, sparsely pilose; receptacle 3-6 × 0.5-1 mm; paleae straw-colored or sometimes with purple tinge early in flowering, 2.5-3.5 × 0.5 mm. Ray florets 4-7; corollas yellow to orange-yellow, 1.5-3.5 mm, tube 0.5-1.5 mm, lamina 3-toothed, 1-2 × 0.5-1.5 mm. Disk florets 68-148, yellow to orange-yellow, 4-merous; corollas 1-1.6 mm, tube 0.2-0.5 mm, throat 0.7-1.2 mm, lobes triangular, 0.2-0.3 × 0.2 mm. Achenes black, 1.2-1.8 mm, moderately to densely ciliate with straight-tipped hairs; pappus of 2 subequal or unequal bristles, longer one 0.2-0.7 mm, shorter one 0.1-0.5 mm (Flora of China Editorial Committee, 2014).

A. uliginosa is a weed which is often used as a medicinal herb. Therefore, it is probable that introductions of this species into new habitats have resulted from the plant escaping after intentional or careless introductions. A. uliginosa is reported as “recently introduced and naturalized” in Japan, and in Taiwan it was reported as naturalized as recently as 2007 (Chung et al., 2007; Flora of China Editorial Committee, 2014; PIER, 2014). It was reported as a new record for Chhattisgarh state, India, in 2014 (Tiwari and Ansari, 2014).

Soil drainage

• free
• seasonally waterlogged

Soil reaction

• acid
• alkaline
• neutral

Soil texture

• heavy
• light
• medium

A. uliginosa spreads by seeds. Plants produce numerous small seeds < 2 mm) which can be easy dispersed by wind and water and also as a contaminant in soil, agricultural machinery and crops (Chung et al., 2007; PIER, 2014; PROTA, 2014). 

A. uliginosa grows a weed, and under suitable conditions it has the potential to rapidly colonize disturbed areas. This species represents a conservation concern principally in insular ecosystems in the West Indies and the Pacific islands (i.e., New Caledonia, Fiji, and Micronesia) where it has become invasive (Smith, 1991; MacKee, 1994; Herrera et al., 2010; PIER, 2014). 

• Proved invasive outside its native range
• Has a broad native range
• Abundant in its native range
• Highly adaptable to different environments
• Is a habitat generalist
• Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
• Pioneering in disturbed areas
• Highly mobile locally
• Benefits from human association (i.e. it is a human commensal)
• Fast growing

• Modification of successional patterns
• Monoculture formation
• Negatively impacts agriculture
• Reduced native biodiversity
• Threat to/ loss of native species

• Competition - monopolizing resources
• Rapid growth

• Highly likely to be transported internationally accidentally
• Difficult to identify/detect as a commodity contaminant

A. uliginosa has been used as a therapeutic herb for its medicinal properties as a pain-reliever (Graveson, 2012; PROTA, 2014). In Benin it is a traditional leafy vegetable which has been domesticated in rural areas (Eteka et al., 2010).