Hydrocotyle ranunculoides L. f., Araliaceae

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Present on Pacific Islands?  no

Primarily a threat at high elevations?  no

Common name(s): [more details]

English: floating pennywort, water pennywort

Habit:  herb

Description:  "Plants entirely glabrous, the stems fleshy, floating in water or creeping. Leaves non-peltate, suborbicular to reniform and frequently broader than long, 0.5-8 cm in diameter, shallowly to rather deeply 3-7-lobed, the lobes rounded, crenate or lobulate, subequal. Petioles 1-35 cm long. Peduncles much shorter than the leaves, 0.5-6 cm long. Umbels 3-8-flowered, the petals greenish-white. Involucral bracts oval to orbicular, up to 1 mm long. Styles much shorter than fruit width, spreading, the stylopodium depressed. Pedicels 1-3 mm long, spreading. Fruit suborbicular to transversely elliptical, moderately flattened, 1.5-2.5 mm long, 2-3 mm broad, often maculate, the ribs filiform or obscure" (Mathias & Constance, 1976; p. 22).

Habitat/ecology:  Aquatic. "Dense growth can smother static or slowly flowing waterways, particularly in nutrient-rick waters" (Csurhes & Edwards, 1998).  "Naturalized populations exist in coastal, freshwater streams of Western Australia, where it is reported to have escaped from ornamental garden ponds" (Keighery, 1994, cited in Csurhes & Edwards, 1998; p. 167).

Propagation:  Rooting at nodes, stem fragments, seed.

Native range:  North and South America, Africa, Yemen; naturalized elsewhere (GRIN).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Kiribati Line Islands	Teraina (Washington) Island	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)

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)	Australia (continental)	introduced invasive	Csurhes, S./Edwards, R. (1998) (p. 167) Western Australia; subject of an eradication program.
British Columbia (province of Canada) Province of British Columbia	Canada (British Columbia)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Costa Rica (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Guatemala (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Nicaragua (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Panama (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Mexico Mexico	Mexico (United Mexican States)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
South America (Pacific rim) South America (Pacific rim)	Chile (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
South America (Pacific rim) South America (Pacific rim)	Colombia		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 186)
South America (Pacific rim) South America (Pacific rim)	Ecuador (Republic of) (continental)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
South America (Pacific rim) South America (Pacific rim)	Perú (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (west coast) United States (west coast states)	USA (Oregon)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (west coast) United States (west coast states)	USA (California)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (west coast) United States (west coast states)	USA (Washington)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)

Also reported from
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
United States (continental except west coast) United States (other states)	United States (other states)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (continental except west coast) United States (other states)	USA (Florida)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)

Control:  If you know of control methods for Hydrocotyle ranunculoides, please let us know.