Mitracarpus hirtus (L.) DC., Rubiaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Mitracarpus villosus (Sw.) Cham. & Schltdl. ex DC.; Spermacoce hirta L.; Spermacoce villosa Sw.

Common name(s): [more details]

Chinese: gai lie guo

English: small squareweed, tropical girdlepod

Habit:  herb

Description:  "Annual herbs; stems erect or spreading, 2-4 dm long, branched or unbranched, pubescent with sort, curly hairs and appressed hairs, also usually villous on the angles, outer epidermis exfoliating.  Leaves elliptic to elliptic-lanceolate, 2-6 cm long, 0.5-1.5 (-2) cm wide, upper surface scabrid to glabrate, lower surface glabrous except puberulent along veins and usually scabrid near margins, apex acute, base cuneate, subsessile, stipules 1-3 mm long, with 6-9 (-15) setae 1-5 mm long, their margins ciliate, often tipped with colleters.  Flowers sessile or nearly so, in dense axillary clusters, stipule-derived bracteoles filamentous, 1-2 mm long; hypanthium 1-1.4 mm long; calyx lobes 4, 2 of them oblong-lanceolate, with hyaline margins, 1.3-2.3 (-3) mm long, the other 2 deltate-lanceolate, 0.5-1.5 mm long, pubescent in lower part and ciliate; corolla white, 2-3 mm long.  Capsules subglobose, ca. 1 mm long.  Seeds pale yellowish brown, ellipsoid-rectangular, compressed, 0.8-0.9 mm long, the dorsal face resembling a rectangle with a square portion removed from each corner, ventrally separated into 4 discrete areas by 4 impressed lines arising at the hilum"  (Wagner et al., 1999; p. 1156).

Habitat/ecology:  In Fiji, "an occasional weed near sea level along roadsides, in pasture plots, and along beaches"  (Smith, 1988; pp. 375-376).  In Hawai‘i, "recently naturalized in disturbed mesic sites" (Wagner et al., 1999; p. 1156).

Propagation:  Seed

Native range:  Neotropics (Wagner et al., 1999; p. 1156). Exact native range obscure; widely naturalized (GRIN).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Rota Island	introduced	Raulerson, L. (2006) (p. 65)
Commonwealth of the Northern Mariana Islands (US) Saipan	Saipan Island	introduced	Raulerson, L. (2006) (p. 65)
Fiji Fiji Islands	Viti Levu Island	introduced invasive	Smith, Albert C. (1988) (pp. 375-376) Vouchers cited: DA 10111, 11596, DA 15360
Guam Guam Island	Guam Island	introduced invasive	Stone, Benjamin C. (1970) (p. 551)
Guam Guam Island	Guam Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 271) As Mitracarpum hirtum.
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1156) Voucher cited: Wagner & Stemmermann 4631 (BISH)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Starr, Forest/Starr, Kim/Loope, Lloyd L. (2003) (p. 31) East Maui. Voucher cited: Starr & Martz 010726-2 (BISH)
Palau Palau (Belau ) (main island group)	Babeldaob Island	introduced invasive	Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (p. Field notes.)
Palau Palau (Belau ) (main island group)	Babeldaob Island	introduced	Fosberg, F. R./Sachet, M.-H./Oliver, R. L. (1993) (p. 90) Vouchers cited: Timberlake 3047 (US), Raulerson 5878 (US), Raulerson 5693 (US)
Palau Palau (Belau ) (main island group)	Babeldaob Island	introduced invasive	Space, James C./Lorence, David H./LaRosa, Anne Marie (2009) (p. 64) Voucher: Lorence 9930 (PTBG, BNM)
Palau Palau (Belau ) (main island group)	Babeldaob Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (2008) (voucher ID: PTBG 223) Taxon name on voucher: Mitracarpus hirtus (L.) DC.
Palau Palau (Belau ) (main island group)	Babeldaob Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1998) (voucher ID: PTBG 28069) Taxon name on voucher: Mitracarpus hirtus (L.) DC.
Palau Palau (Belau ) (main island group)	Koror (Oreor) Island	introduced invasive	Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (p. 98)
Palau Palau (Belau ) (main island group)	Malakal (Ngemelachel) Island	introduced invasive	Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (p. 98)
Palau Palau (Belau ) (main island group)	Ngerkebesang Island	introduced invasive	Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (p. 98)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Central America Central America (Pacific rim)	Costa Rica (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	El Salvador (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Guatemala (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Honduras (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Nicaragua (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Panama (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
China China	China (People's Republic of)	introduced invasive	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013) Wastelands at highway sides; near sea level to 800 m. Hainan (Wanning), Hong Kong, Yunnan, Xinjiang.
Indonesia Indonesia	Indonesia (Republic of)	introduced invasive	Waterhouse, D. F. (1993) (pp. 67, 78)
Malaysia Malaysia	Malaysia (country of)	introduced invasive	Waterhouse, D. F. (1993) (pp. 67, 78)
Mexico Mexico	Mexico (United Mexican States)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Singapore Singapore	Singapore (Republic of)	introduced invasive	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 61) Naturalised
South America (Pacific rim) South America (Pacific rim)	Colombia	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
South America (Pacific rim) South America (Pacific rim)	Ecuador (Republic of) (continental)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Thailand Thailand	Thailand (Kingdom of)	introduced invasive	Waterhouse, D. F. (1993) (pp. 67, 78)

Indian Ocean
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Seychelles Seychelles Islands	Seychelles Islands	introduced	Invasive Species Specialist Group (2017)

Also reported from
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
United States (continental except west coast) United States (other states)	United States (other states)	introduced	U.S. Dept. Agr., Agr. Res. Serv. (2013) Georgia, Lousiana, Mississippi, Texas
United States (continental except west coast) United States (other states)	USA (Florida)	introduced	U.S. Dept. Agr., Agr. Res. Serv. (2013)

Control:  If you know of control methods for Mitracarpus hirtus, please let us know.