Persicaria lapathifolia (L.) Gray, Polygonaceae

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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)	Australia (continental)		Hafliger, Toni J./Wolf, Matthias (1988) (p. 286)
Australia Australia (continental)	New South Wales	introduced invasive	Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 611)
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)
Chile (continental) Chile	Chile (Republic of)	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. (2011)
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. (2011)
Japan Japan	Japan (country)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
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".
Taiwan Taiwan	Taiwan Island	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Thailand Thailand	Thailand (Kingdom of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Vietnam Vietnam	Vietnam (Socialist Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)

Additional information:
Additional online information about Persicaria lapathifolia is available from the Hawaiian Ecosystems at Risk project (HEAR).

Information about Persicaria lapathifolia as a weed (worldwide references) may be available from the Global Compendium of Weeds (GCW).

Taxonomic information about Persicaria lapathifolia may be available from the Germplasm Resources Information Network (GRIN).

References:

Atkinson, Rachel/Sawyer, John. 2011. Naturalized species in the Juan Fernández Archipelago, Chile. Unpublished spreadsheet.

Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido. 2006. Nouveau catalogue de la flore vaculaire de l'archipel Juan Fernández (Chile) [Nuevo catálogo de la flora vacular del Archipélago Juan Fernández (Chile)]. Acta Bot. Gallica 153(4):399-587.

Hafliger, Toni J./Wolf, Matthias. 1988. Dicot weeds, vol. 1. CIBA-GEIGY Ltd., Basle, Switzerland. 335 pp.

Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James. 1997. World weeds: natural histories and distribution. John Wiley & Sons. 1129 pp.

Li-ying, Li/Ren, Wang/Waterhouse, D. F. 1997. The distribution and importance of arthropod pests and weeds of agriculture and forestry plantations in southern China. ACIAR, Canberra, Australia. 185 pp.

U.S. Dept. Agr., Agr. Res. Serv. 2011. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.

U.S. Dept. Agr., Nat. Res. Cons. Serv. 2011. The PLANTS Database. National Plant Data Center, Baton Rouge, LA 70874-4490 USA.

Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. 1988. Flora of New Zealand, Volume IV: Naturalised pteridophytes, gymnosperms, dicotyledons. Botany Division, DSIR, Christchurch. 1365 pp.

Womersley, John S., ed. 1978. Handbooks of the flora of Papua New Guinea, vol. 1. Melbourne University Press, Melbourne. 278 pp.

Wu, Te-lin. 2001. Check List of Hong Kong Plants. Hong Kong Herbarium and the South China Institute of Botany. Agriculture, Fisheries and Conservation Department Bulletin 1 (revised). 384 pp.

Zhengyi, Wu/Raven, Peter H./Deyuan, Hong. 2011. Flora of China (online resource).