Rumex obtusifolius L., Polygonaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

Chinese: dun ye suan mo

English: bitter dock, bluntleaf dock, broad-leaved dock, broadleaf dock, celery seed

French: oseille, parelle, patience à feuilles obtuses, patience sauvage, rumex à feuilles obtuses

Japanese: ezo-no-gishi-gishi

Spanish: acedera de hojas obtusas, acedera obtusifolia, bijuaca, engorda puercos, lengua de vaca, romaza de hojas grandes, romaza vulgar, vinagrillo, yerba mulata

Habit:  herb

Description:  "Erect perennial herbs; stems 6-12 dm long, striate, glabrous.  Leaves oblong-ovate to oblong-lanceolate, basal ones usually 25-45 cm long, 9-11 cm wide, cauline leaves 6-30 cm long, 2-11 cm wide, upper surface usually glabrous, lower surface usually papillose-pilose along veins, occasionally glabrous, margins subentire to erose, undulate, apex acuminate to obtuse, base truncate to subcordate, petioles usually 2-9 cm long, those of basal leaves up to 25 cm long.  Flowers unisexual (and the plants monoecious), usually 14-24 in clusters, these arranged in racemose, sometimes branched inflorescences; staminate flowers with outer tepals 0.8-1 mm long, the valves membranous, 1-1.3 mm long; pistillate flowers with outer tepals 1-1.2 mm long, the valves membranous, 1.5-2 mm long, enlarging to 4-5 mm long and becoming narrowly cordate in fruit, margins with straight or slightly curved teeth, some of which are 1-1.2 mm long, at least 1 of the valves with a tubercle, the tubercles unequal, 0.6-2 mm long.  Nuts dark brown, 2-2.4 mm long, the surface glossy"  (Wagner et al., 1999; p. 1069).

Habitat/ecology:  In Hawai‘i, "naturalized in relatively mesic, disturbed areas and sometimes in areas dominated by native species, 600-1,470 m" (Wagner et al., 1999; p. 1069). In New Zealand, "usually near habitations, also common to abundant elsewhere in pastures, river banks and open moist places, and a major weed of gardens and arable land. Plants are often very large and prolific around stockyards, cowsheds and other places with very high nitrogen levels" (Webb et al., 1988; p. 984).

Propagation:  Seed. "The fruits...are lightweight and may be moved long distances by wind.  They are also spread by moving in water and by adhering with mud to the clothes of man, his machinery, and the fur, feathers, and feet of animals" (Holm et al., 1977; p. 405).

Native range:  Europe (Wagner et al., 1999; p. 1069).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1069) Subsp. obtusifolius. Voucher cited: Rock 3464 (BISH)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1069) Subsp. obtusifolius
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1069) Subsp. obtusifolius

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. 308)
China China	China (People's Republic of)	native	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013) "Field margins, moist valleys; sea level to 100 m".
Japan Japan	Japan	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Japan Japan	Japan	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 181) var. agrestis (Fries) Celak
Mexico Mexico	Mexico (United Mexican States)		Hafliger, Toni J./Wolf, Matthias (1988) (p. 308)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 984)
South America (Pacific rim) South America (Pacific rim)	Chile (Republic of)		Hafliger, Toni J./Wolf, Matthias (1988) (p. 308)
South America (Pacific rim) South America (Pacific rim)	Colombia		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 315)
Taiwan Taiwan Island	Taiwan Island	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
La Réunion (France) La Réunion Island	La Réunion Island	introduced invasive	Lavergne, Christophe (2006) "Naturalisé/±envahissant"

Control:  If you know of control methods for Rumex obtusifolius, please let us know.