Ludwigia longifolia (DC.) H. Hara, Onagraceae

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Present on Pacific Islands?  no

Primarily a threat at high elevations?  no

Other Latin names:  Jussiaea longifolia DC.

Common name(s): [more details]

English: longleaf primrose-willow

Habit:  herb

Description:  "Erect glabrous herbs 0.5-2.5 m tall, rarely persisting beyond the first year. Stem profusely branched, sharply 4-angled and winged, sometimes woody and subterete below, glabrous. Stipules 0.4-0.5 mm long, ca. 0.1 mm wide, setaceous. Leaves 5-35 cm long, 0.4-2.5 cm wide, oblong-lanceolate or lanceolate, acute or short acuminate at tip, obtuse or acute at base, thick or membranous, subentire, often minutely scabrid and sometimes reddish along margin, with 20-38 pairs of veins on each side of midrib; secondary veins few and anastomosing; submarginal vein prominent. Bracts gradually reduce in size, the smallest ones setaceous. Pedicels 5-42 mm, sharply 4-angled, narrowly winged, glabrous. Bracteoles 5-7 mm long, 0.2-2.5 mm wide, setaceous or lanceolate, acute at tip, obtuse or acute below, entire, occasionally scabrid, subtended by reduced, gland-like, stipellar glands ca. 1 mm long and wide, deciduous, borne on upper half of pedicel or base of ovary. Sepals 4 (-5), 1-1.8 cm long, 0.3-0.55 cm wide, broadly ovate or ovate, acuminate, sometimes minutely scabrid along margin, glabrous, green or often red or pink within, 5-7-nerved. Petals 2-2.5 cm long, 2-2.3 cm wide, suborbicular or obovate and then emarginate, bright yellow. Stamens subequal; filaments 2.5-3.5 mm long, yellow; anthers 3.5-4.5 mm long, 0.5-0.8 mm thick, yellow; filaments spreading flat on the petals at anthesis, gradually curving inward and becoming erect, the anthers then establishing contact with the stigma when it is shorter, though usually the stigma is held above the anthers. Ovary 8-32 mm long, 2-5 mm thick, sharply 4-angled, narrowly oblong or oblong, narrowed into the pedicel, glabrous or puberulent. Disk plane. Style 3-5 mm long, 0.5-0.8 mm thick, yellow; stigma 4-6 mm long, 2-2.5 mm thick, oblong or sometimes globose, minutely papillose. Capsule 1.1-3.5 (-4.2) cm long, 0.4-0.8 cm thick, sharply 4-angled, oblong or narrowly oblong, gradually terete with age, glabrous or puberulent. Seeds numerous, 0.5-0.8 mm long, 0.2-0.3 mm thick, oblong, straight or slightly curved, brown, striate; raphe very reduced, produced into a blunt end" (Ramamoorthy & Zardini, 1987; pp. 80-84).

Similar species:  Ludwigia peruviana.

Habitat/ecology:  Swamps and marshes (Ramamoorthy & Zardini, 1987; pp. 80-84). "Tropical and sub-tropical wetlands and riparian vegetation" (Csurhes & Edwards, 1998; p. 43).

Propagation:  Seed

Native range:  "Central Bahia, Brazil, south to Buenos Aires, Argentina, and from Espiritu Santo, Brazil, to Tucaman, northwestern Argentina" (Ramamoorthy & Zardini, 1987; pp. 80-84).

Presence:

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)	New South Wales	introduced invasive	Csurhes, S./Edwards, R. (1998) (p. 43)
Australia Australia (continental)	New South Wales	introduced invasive cultivated	National Herbarium of New South Wales (2013) "Escaped garden plant. Declared noxious weed."

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)	USA (Florida)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)

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