Ludwigia adscendens (L.) H. Hara, Onagraceae

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Present on Pacific Islands?  no

Primarily a threat at high elevations?  no

Other Latin names:  Jussiaea adscendens L.; Jussiaea repens L.

Common name(s): [more details]

Chinese: shui long

English: creeping waterprimrose, red ludwigia, water primrose

Japanese: mizukinbai

Spanish: clavito, clavo de agua, mimbra

Habit:  aquatic herb

Description:  "An aquatic or sub-aquatic perennial herb that may be emergent, may be anchored, with horizontal extensions over the water surface, or may be free floating; stems to 1 m, horizontal stems to 4 m, normally glabrous but if water recedes, plants may survive on dry ground where they are densely villous and seldom flower, horizontal stems with long, fibrous roots, as well as adventitious, modified, spindle-shaped, nodal aerophores or air roots, that grow erect and may extend above the water surface, in South Asia stems are yellow-green or reddish in some areas; leaves alternate, broadly oblong-elliptic, rounded or obtuse at apex, up to 10 cm long, 4 cm wide, narrowed at the base to a distinct petiole which may be red; flowers borne singly at upper leaf axils, 5-merous, pediceled; calyx pubescent or sometimes glabrous; petals obovate, bright yellow to very pale yellow or white, up to 2 cm long; stamens 10, the epipetalous ones are slightly shorter, filaments white, 2.5 to 4 mm; anthers are 1.2 to 1.8 mm long shedding pollen directly onto stigma at anthesis; style white, 4 to 8 mm, densely long hairy on lower half; stigma globose, green, upper two-thirds receptive, ovary inferior; fruit a capsule thick-walled, woody, 2 to 3 cm long and 3 mm in diameter, more or less cylindrical, often some-what curved, surmounted at apex by calyx, glabrous or with soft long hairs, 5-locular, light brown with 10 conspicuous darker brown ribs, seeds evident as bumps between the ribs, irregularly dehiscent, base narrowed; seeds pale brown, many in orderly rows, some 4-angled and some prismoid, 1 to 2 mm in size, firmly imbedded in coherent cubes of woody endocarp which are fused to capsule wall.  This species is distinguished from L. hyssopifolia and L. octovalvis by its broader, more rounded leaves"  (Holm et al., 1997; pp. 444-445).

Habitat/ecology:  "It south Asia during the rainy season the weed frequents irrigation channels, tanks (artificial ponds for water storage), small lakes, and cultivated crops such as rice and jute.  It may be seen from sea level to 1600 m.  The plant thrives on a variety of soils in the rice paddies of the world" (Holm et al., 1997; p. 445). In New Guinea (native), "generally confined to swamps and not troublesome as a weed, but dangerous to livestock when they have access to it. From low altitudes to 750 m" (Henty & Pritchard, 1975; p. 128); lowland fresh-water pools and swamps, edge of rivers and lakes and inundated ditches and canoe channels to c. 760 m altitude, mainly aquatic"  (Conn, 1995; p. 209).  In Sri Lanka, "often common or abundant, in flooded paddy fields, or floating in water at margins of ponds, tanks or ditches; low elevations" (Dassanayake, 1983; p. 341).

Propagation:  "Propagation is mainly by seed, but extensive creeping stems, on mud or water, may help a single plant to colonize a significant area.  If the water level recedes, the stems resting on soil produce roots, and a bud at each node may provide a new shoot.  Propagation from broken pieces of floating stems is quite normal" (Holm et al., 1997; p. 445).

Native range:  India to southeastern Asia and Malesia; China and Australia (Dassanayake, 1983; p. 341).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)	native	Henty, E. E./Pritchard, G. H. (1975) (p. 128) From low altitudes to 750 m.
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)	native	Conn, Barry J., ed. (1995) (pp. 208-209)
Philippines Philippine Islands	Philippine Islands	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Philippines Philippine Islands	Philippine Islands	native	Merrill, Elmer D. (1923) (pp. 219-220) As Jussiaea repens L. In shallow water of quiet streams, shallow lakes, and fresh-water swamps at low and medium altitudes.

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)	Northern Territory	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Australia Australia (continental)	Queensland	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Cambodia Cambodia	Cambodia (Kingdom of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Honduras (Republic of)		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 221)
Central America Central America (Pacific rim)	Nicaragua (Republic of)		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 452)
China China	China (People's Republic of)	native	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013) Wet swampy places, flooded rice paddies, often floating in water at edges of ponds, tanks, ditches; near sea level to 1600 m. Fujian, Guangdong, Guangxi, Hainan, Hunan, Jiangxi, Yunnan, Zhejiang.
China China	Hong Kong	native	Wu, Te-lin (2001) (p. 165)
Indonesia Indonesia	Indonesia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Japan Japan	Japan		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 442)
Malaysia Malaysia	Malaysia (country of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Mexico Mexico	Mexico (United Mexican States)		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 442)
Singapore Singapore	Singapore (Republic of)	uncertain if introduced invasive	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 57) Weed of uncertain origin
South America (Pacific rim) South America (Pacific rim)	Chile (Republic of)		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 442)
South America (Pacific rim) South America (Pacific rim)	Colombia		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 442)
South America (Pacific rim) South America (Pacific rim)	Perú (Republic of)		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 442)
Taiwan Taiwan Island	Taiwan Island	native	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013) Wet swampy places, flooded rice paddies, often floating in water at edges of ponds, tanks, ditches; near sea level to 1600 m.
Taiwan Taiwan Island	Taiwan Island	native	Ching-I Peng, ed. (2013) " In paddy fields and about ponds in the lowland of the southern and southeastern part of the island".
Thailand Thailand	Thailand (Kingdom of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Vietnam Vietnam	Vietnam (Socialist Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)

Indian Ocean
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Mauritius Mautitius Islands (Mauritius and Rodrigues)	Mauritius Island		Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 442)

Control:  If you know of control methods for Ludwigia adscendens, please let us know.