Acmella

Scientific name

Acmella Pers.

Common names

spotflower

Family

Asteraceae

Similar genera

Bidens, Hemigraphis, Hyptis, Mentha, Pilea, Sphagneticola

Native distribution

New World Tropical

Species cultivated

Acmella oleracea (L.) R.K. Jansen

A. repens (Walter) Rich. Ex Pers.

Adventive distribution

introduced to Asia, Africa, Australia, Pacific Islands

Weed status

not weedy

Habit

prostrate prostrate:
(adj) growing closely along the ground
or erect herbs

Brief description

Annual or perennialperennial:
(adj) (of a plant) having a life cycle of more than two years
. Stem prostrateprostrate:
(adj) growing closely along the ground
to erect. Leaves oppositeopposite:
(adj) (of leaves) two leaves per node; in pairs on opposite sides of an axis
, decussatedecussate:
(adj) arranged along stem in pairs, with each pair at right angles to the pairs above and below
; leaf bladeblade:
(n) (syn. lamina) the flat, expanded part of a leaf, frond, or petal (excluding, e.g., the petiole)
lanceolate to ovateovate:
(adj) egg-shaped in outline; generally with the broad end at or near the base
, sparsely hairy; apexapex:
(n) the point farthest from the point of attachment; the tip (often pointed)
round to acuteacute:
(adj) tapering to a sharp, pointed apex with more or less straight sides; broader than acuminate; forming an angle of less than 90 degrees
; base round to attenuateattenuate:
(adj) narrowing gradually to a point
; marginmargin:
(n) edge; rim
entireentire:
(adj) having a continuous margin that is not toothed or lobed
to toothed. Inflorescenceinflorescence:
(n) the arrangement of flowers on the floral axis
terminal, a solitary headhead:
(n) inflorescence consisting of small closely packed stalkless flowers or florets arising at the same level on a flattened axis; of several types, including: discoid (composed entirely of disk flowers) and radiate (composed of central disk flowers and marginal ray flowers)
or a few heads in cymes; radiate or discoid. Involucreinvolucre:
(n) a whorl of bracts subtending a flower, flower cluster, or inflorescence
± hemispheric; phyllariesphyllary:
(n) an individual bract of the involucre in Asteracea flower heads
1-3-seriate, subequal or outer longer, entireentire:
(adj) having a continuous margin that is not toothed or lobed
or irregularly dentatedentate:
(adj) (of a leaf margin) (1) toothed; (2) bearing shallow teeth projecting outward from midrib
; receptaclereceptacle:
(n) the portion of the pedicel on which the flowers are borne, or in the Asteraceae, the portion of the peduncule upon which the florets of the head are borne
conicalconical:
(adj) perfectly cone-shaped
; paleate. Ray florets, when present, 2-3-lobed; pistillate; typically yellow to orange. Disk florets of 4-5 triangular, yellow or orange lobes.

Natural habitat

riparian, flood zones on river banks, pond edges, and in wet ditches

Additional comments

A genus of 30 species. The species Acmella repens (Walter) Rich. ex Pers. is semi-aquatic to aquatic, typically with floating stems; also known as Acmella oppositifolia var. repens (Walter) R.K.Jansen.