Persicaria lapathifolia (L.) Gray, Polygonaceae

Click on an image for links to BIGGER PICTURES

Present on Pacific Islands?  no

Primarily a threat at high elevations?  no

Other Latin names:  Polygonum lapathifolium L.

Common name(s): [more details]

Chinese: ma liao

English: bulbous persicaria, curlytop knotweed, dock-leaved smartweed, pale knotweed, pale persicaria, pale smartweed, pale willow weed, willow weed

French: renouée à feuilles de patience, renouée nouesuse, renouée pâle, saulcette

Japanese: o-inu-tade, sanaetade

Spanish: duraznillo, persicaria mayor, poligono pata de perdiz

Habit:  herb

Description:  "Annual herb; stems weak (ascending) or stout (erect), 30 to 120 cm tall, green or reddish, jointed, swollen above the nodes, hollow, branched, smooth; may root at lower nodes; upper stems rough or gummy due to presence of glands; ochrea cylindrical, membranous, smooth, greenish, often tinged with red, strongly veined, 1 to 1.5 cm long, devoid of apical hairs; leaves alternate, broadly lanceolate, 5 to 16 cm long, long-pointed at apex, wedge-shaped at base; margin fringed with hairs and sunken, pellucid glands on lower surface; upper leaf surface nearly smooth, often with a dark triangular spot near the center; petiole to 3 cm long; inflorescence a densely flowered spike, drooping or nodding, terminal or axillary, 3 to 10 cm long on slightly glandular peduncles; flowers perfect, greenish white or pinkish; stamens 5 to 7, longer than perianth; perianth 4- or 5-lobed, glandular, persistent, with raised anchor-shaped veins on outer segments; veins longer than fruits and fold around achenes forming air-filled "beak" over remains of stigma; fruit an achene, usually lenticular, 1.5 to 3 mm long, 1.3 to 1.8 mm wide, broadly ovate to circular with apex elongated to a point, flattened with thickened edges, brown shiny black and finely granular.  The hollow stem that is swollen above the nodes, leaves with sunken glands on the lower surface, nodding spikes and flattened seeds are the distinguishing characteristics of this plant"  (Holm et al., 1997; p. 613).

Description from Flora of North America

Habitat/ecology:  "It is common in cultivated land, roadsides and waste areas, especially along streams, ditch banks and in other wet and poorly drained areas.  Plants tolerate many edaphic conditions and climates, and are often found along streams and river banks, growing best in loose, slightly acid, nutrient-rich soils high in organic matter"  (Holm et al., 1997; pp. 611, 613).

In Papua New Guinea, "so far found only above 1500 m; 'common in old ditches' (Baliem River); 'roadside' (lower slopes of Mt. Wilhelm)"  (Womersley, 1978; p. 236).

Propagation:  Seed.  The seeds float and can be distributed by water.  They can be distributed as feed and crop seed contaminants or eaten and excreted by animals  (Holm et al., 1997; pp. 613-614).

Native range:  Europe, now widespread, mostly in temperate regions (Holm et al., 1997; p. 611). Europe, Asia and north Africa; widely naturalized, exact native range obscure (GRIN)

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Chile (offshore islands) Juan Fernández Islands	Isla Más a Tierra (Robinson Crusoe Island)	introduced invasive	Atkinson, Rachel/Sawyer, John (2011) As Polygonum lapathifolium L.
Chile (offshore islands) Juan Fernández Islands	Isla Más a Tierra (Robinson Crusoe Island)	introduced invasive cultivated	Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (p. 556) As Polygonum lapathifolium L.
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)	possibly introduced	Womersley, John S., ed. (1978) (pp. 235-236)

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	Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 611)
Australia Australia (continental)	Australia (continental)		Hafliger, Toni J./Wolf, Matthias (1988) (p. 286)
Australia Australia (continental)	Northern Territory	introduced invasive	Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 611)
Australia Australia (continental)	Queensland	introduced invasive	Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 611)
China China	China (People's Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
China China	China (People's Republic of)		Li-ying, Li/Ren, Wang/Waterhouse, D. F. (1997) (p. 174)
China China	Hong Kong	native	Wu, Te-lin (2001) (p. 83)
Indonesia Indonesia	Indonesia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Japan Japan	Japan	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
South Korea South Korea	South Korea (Republic of)	native	Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997)
Mexico Mexico	Mexico (United Mexican States)	introduced invasive	Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 611)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 973) "Usually waste and arable land, also open disturbed, particularly moist habitats".
South America (Pacific rim) South America (Pacific rim)	Chile (Republic of)	introduced invasive	Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 611)
Taiwan Taiwan Island	Taiwan Island	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
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)

Control:  If you know of control methods for Persicaria lapathifolia, please let us know.