Persicaria capitata (Buch.-Ham. ex D.Don) Masamune, Polygonaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  High risk, score: 13 (Go to the risk assessment)

Other Latin names:  Polygonum capitatum Buch.-ham. ex D. Don

Common name(s): [more details]

English: pinkhead knotweed, pinkhead smartweed

French: couvre-sol, herbe corail

Habit:  herb

Description:  "Mat-forming perennial herbs from a stout woody root; stems prostrate, sometimes rooting at the nodes, 0.5-3.5 dm long, many-branched.  Leaves with a conspicuous purple V-shaped band, occasionally also tinged red or purple, elliptic-ovate to elliptic, 1-4 (-6.2) cm long, 0.6-2.5 (-3.3) cm wide, both surfaces sparsely strigillose, margins glandular ciliate, petioles 1-4 mm long, glandular villous, usually with an auricle that clasps the stem, ocreae reddish brown, tubular, to 6-10 mm long, glandular hirsute, apex glandular ciliate.  Flowers in subglobose or capitate spikes, these 1 to several at the ends of the branches, peduncles with purple glandular hairs; tepals pink, 2-2.5 mm long.  Nuts dark reddish brown, trigonous, ca. 2 mm long, apex beaked, the surface somewhat striate, glossy"  (Wagner et al., 1999; p. 1063).

Habitat/ecology:  In Hawai‘i, "naturalized in wet forest, open lava fields, and along roadsides, 600-1,770 m" (Wagner et al., 1999; p. 1063).

Propagation:  Seed

Native range:  Himalayas and western China, widely cultivated (Wagner et al., 1999; p. 1063).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Guam Guam Island	Guam Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 66)
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 1060, 1063, 1888)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 1060, 1063, 1888)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Oppenheimer, Hank L./Bartlett, Randal T. (2002) (p. 11) East Maui. Voucher cited: Oppenheimer H70069 (BISH)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 1060, 1063, 1888)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
China China	China (People's Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2009)
Malaysia Malaysia	Malaysia (country of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2009)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 972) "Cultivation escape, steep banks, crevices of walls and amongst rocks near habitations, also less modified habitats such as coastal cliffs".
Thailand Thailand	Thailand (Kingdom of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2009)
Vietnam Vietnam	Vietnam (Socialist Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2009)

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	MacDonald, I. A. W./Thebaud, C./Strahm, W. A./Strasberg, D. (1991) (pp. 51-61)
La Réunion (France) La Réunion Island	La Réunion Island	introduced invasive cultivated	Lavergne, Christophe (2006) "Cultivé/envahissant"

Additional information:
Photos and additional information at the Environment Bay of Plenty, New Zealand, web site of the Bay of Plenty Regional Council.

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

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

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

References:

Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce. 1979. A geographical checklist of the Micronesian dicotyledonae. Micronesica 15:1-295.

Lavergne, Christophe. 2006. List des especes exotiques envahissantes a La Reunion. Unpublished manuscript (Excel file). .

MacDonald, I. A. W./Thebaud, C./Strahm, W. A./Strasberg, D. 1991. Effects of alien plant invasions on native vegetation remnants on La Reunion (Mascarenes Islands, Indian Ocean). Environmental Conservation 18 (1):51-61.

Oppenheimer, Hank L./Bartlett, Randal T. 2002. New plant records from the main Hawaiian Islands. In: Evenhuis, Neal L. and Eldredge, Lucius G., eds. Records of the Hawaii Biological Survey for 2000. Part 2: Notes. Bishop Museum Occasional Papers. 69:1-14.

U. S. Government. 2009. Integrated Taxonomic Information System (ITIS) (on-line resource).

U.S. Dept. Agr., Agr. Res. Serv. 2009. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.

Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. 1999. Manual of the flowering plants of Hawaii. Revised edition. Bernice P. Bishop Museum special publication. University of Hawai‘i Press/Bishop Museum Press, Honolulu. 1919 pp. (two volumes).

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.