Rumex conglomeratus Murr., Polygonaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Rumex foliosus Rech. f.

Common name(s): [more details]

English: clustered dock, clustered green dock, green dock, sharp dock

French: rumex aggloméré

Habit:  herb

Description:  "Plants perennial, normally glabrous, rarely very indistinctly papillose on veins of leaf blades abaxially, with fusiform, vertical rootstock. Stems erect, branched in distal 3 (sometimes with few flowering stems from rootstock), 30-80 (-120) cm. Leaves: ocrea deciduous to partially persistent at maturity; blade oblong-lanceolate, obovate-lanceolate, or lanceolate, normally (5-) 10-30 x 2.5-6 cm, base broadly cuneate, rounded, or truncate, rarely subcordate, margins entire, flat to very weakly undulate, apex subacute, occasionally obtuse. Inflorescences terminal, occupying distal 2/3 of stem, lax, interrupted, broadly paniculate, branches simple or nearly so, almost all but distalmost whorls with subtending leaves; panicle leafy at least in proximal 2/3 of length. Pedicels articulated in proximal 1/3 or occasionally near middle, filiform, 1-4 (-5) mm, ca. as long as inner tepals or slightly longer, articulation distinctly swollen. Flowers 10-20 in dense remote whorls; inner tepals oblong-lanceolate, oblong, or lingulate, 2-3 x 1-1.6 (-2) mm, ca. 2 times as long as wide, base cuneate or truncate, margins entire, apex obtuse; tubercles 3, equal or subequal, largest tubercle almost as wide as inner tepal. Achenes usually dark reddish brown, 1.5-1.8 x 1-1.4 mm"  (Flora of North America online).

"Rumex conglomeratus can be distinguished from other species of Rumex in the Hawaiian Islands by its distinctly interrupted inflorescence, the whorls of flowers widely spaced; fruiting inner tepals oblong and each with a tubercle, these subequal or equal, 1/2-3/4 the tepal width, and tepal margents entire.  The most useful characters for distinguishing R. conglomeratus from R. crispus are the whorls of flowers widely spaced vs. nearly continuous and the tubercles > 1/2 the teapal width vs. < 1/2 the tepal width"  (Wagner et al., 1997; pp. 6061).

Habitat/ecology:  "Floodplains, woodland, streambanks, marshy shores.  Where native, this plant commonly grows in ditches, streamsides, meadows, damp places, and in forest gaps.  It is invasive because it grows in dense patches that may merge to cover large areas, thereby displacing native vegetation and reducing species richness.  Once established, it is a persistent weed"  (Weber, 2003; p. 375).  In New Zealand, "usually damp places such as river banks and beds, ditches, drains and swampy places, also pastures and waste places in high rainfall areas, sometimes just above high tide level on beaches"  (Webb et al., 1988; p. 983).

Propagation:  "The species reproduces by seeds and by vegetative growth from the crown"  (Weber, 2003; p. 375).

Native range:  Northern Africa, Europe and temperate western and central Asia (GRIN).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia (Pacific offshore islands) Norfolk Islands	Norfolk Island	introduced invasive	Orchard, Anthony E., ed. (1994) "A weed of damp pastures".
Chile (offshore islands) Juan Fernández Islands	Isla Más a Tierra (Robinson Crusoe Island)	introduced invasive	Atkinson, Rachel/Sawyer, John (2011)
Chile (offshore islands) Juan Fernández Islands	Isla Más a Tierra (Robinson Crusoe Island)	introduced invasive	Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (p. 557)
Chile (offshore islands) Juan Fernández Islands	Isla Más Afuera (Alejandro Selkirk Island)	introduced invasive	Atkinson, Rachel/Sawyer, John (2011)
Chile (offshore islands) Juan Fernández Islands	Isla Más Afuera (Alejandro Selkirk Island)	introduced invasive	Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (p. 557)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Wagner, Warren L./Shannon, Robynn K./Herbst, Derral R. (1997) (p. 60) Vouchers cited: Wagner et al. 5370 (BISH, US), Flynn & Koob 1902 (US)

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	National Herbarium of New South Wales (2013)
Australia Australia (continental)	Queensland	introduced invasive	National Herbarium of New South Wales (2013)
British Columbia (province of Canada) Province of British Columbia	Canada (British Columbia)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)
Japan Japan	Japan	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 181)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 983)
United States (west coast) United States (west coast states)	USA (Oregon)	introduced invasive	Flora of North America Editorial Committee, eds. (2013)
United States (west coast) United States (west coast states)	USA (California)	introduced invasive	Flora of North America Editorial Committee, eds. (2013)
United States (west coast) United States (west coast states)	USA (Washington)	introduced invasive	Flora of North America Editorial Committee, eds. (2013)

Also reported from
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Canada Canada	Canada	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013) Ontario
United States (continental except west coast) United States (other states)	United States (other states)	introduced invasive	Flora of North America Editorial Committee, eds. (2013)

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