Spermacoce latifolia Blume, Rubiaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Borreria latifolia (Aubl.) K. Schum.

Common name(s): [more details]

English: buttonweed, oval leaf false buttonweed

Palauan: ulechouch

Habit:  herb

Description: 

Genus: "Annual or perennial herbs or small subshrubs; stems prostrate or erect, usually 4-angled, glabrous to hispid or scabrid. Leaves opposite or pseudowhorled, usually lanceolate to ovate or elliptic, sessile or petiolate, stipules adnate to petioles, forming a sheath, margins with 1 to numerous filiform setae.  Flowers usually small, perfect, sessile, in axillary or terminal, usually many-flowered clusters subtended by 1-2 or more pairs of bract-like leaves, stipule-derived bracteoles with setae; hypanthium obovoid, turbinate, or sometimes with intermediate teeth; corolla funnelform or salverform, the tube usually very slender, the lobes (3) 4, spreading, valvate in bud; stamens 4, inserted on corolla tube or throat, usually exserted; ovary 2-celled, ovules 1 per cell, attached to middle of septum; style filiform, exserted.  Fruit either a 2-walved capsule dehiscing from apex downward and the septum disappearing, or of 2 dimorphic mericarps, one dehiscent, the other indehiscent.  Seeds 2, usually glossy brown, oblong, ellipsoid, or ovoid, usually reticulate, ventrally grooved" (Wagner et al., 1999; pp. 1171, 1173).

Species:  "Straggling or prostrate annual herb...with branches to 60 cm high, these quadrangular, narrowly winged, and sparingly hirsute; the corolla is white to purplish"  (Smith, 1988; p. 374).

"Plants annual, usually prostrate or procumbent and often with elongate stems, sometimes erect or nearly so, the whole plant yellowish in the dry state; stems acutely quandrangular or even narrowly winged, glabrous or villosulous; leaves almost sessile, chiefly elliptic, sometimes slightly obovate, about 2-4 cm. long and 1-1.8 cm. broad, acute, pilose or villosulous on both surfaces, the lateral nerves conspicuous; stipule sheath about 1 mm. long, the setae 3.5 mm. long, pilose; flower heads dense and rather few-flowered, mostly axillary and about 1 cm. in diameter; sepals 4, narrowly triangular, 1.5 mm. long, acute, ciliate; corolla white or pale bluish, 3 mm. long, pilose at the apex; style bilobate, with recurved lobes; capsule 3.5 mm. long, subglobose, densely pilose above; the seed light brown, 2.5-3 mm. long, only obscurely reticulate. May be recognized readily by the evident yellowish coloring of the dried plant and by the relatively large almost smooth seeds. The resemblance to Mitracarpus hirtus is rather great"  (Standley & Williams, 1974; 24/11 p. 20).

A key to some Spermacoce species (adapted from Lorence & Flynn, 2006; pp. 4-5):

1.  Mature seed surface with deep transverse grooves, the surface between grooves foveolate:  Spermacoce remota [=Spermacoce assurgens].
1.  Mature seeds with surface variously sculptured but not transversely grooved:  2

2(1).  Calyx lobes consistently 2:  Spermacoce exilis
2.       Calyx lobes 4 (occasionally 2-3 in some flowers of Spermacoce prostrata):  3

3(2).  Leaves, at least the lower ones, distinctly petiolate with petioles 5-10 mm long; corolla tube c. 4-5 mm long; capsule (excluding calyx) 2.5-3.0 mm long; seeds 2.0-2.6 mm long:  Spermacoce latifolia
3.      Leaves sessile or the lower ones with petioles 1-3 (5) mm long; corolla tube 0.5 mm long; capsule (excluding calyx) 1-2 mm long; seeds 0.7-1.8 mm long:  4

4(3).  Calyx lobes 4 (occasionally 2-3 in some flowers), 0.5-0.7 mm long, deltate to narrowly deltate with green midrib and broad pale margins; capsule 1.0-1.1 mm long; seeds 0.7-0.9 mm long, deep purplish-brown, dorsal surface with fewer than 8 vertical rows of deep, circular-rimmed pits:  Spermacoce prostrata
4.      Calyx lobes 4, 0.4-1.1 mm long, narrowly deltate to linear-subulate with green midrib and narrow pale margins; capsule 1.2-2.0 mm long; seeds 1-1.8 mm long, chestnut to purplish-brown, dorsal surface with more than 10 vertical rows of minute, shallow pits:  Spermacoce ovalifolia.

Habitat/ecology:  In Fiji, "sparingly adventive near sea level" (Smith, 1988; p. 374).  In Samoa, "uncommon to occasional in disturbed places" (Whistler, 1988; p. 35).  In Guatemala (native), "damp thickets or fields, sometimes on grassy banks or even in pine forest, at low elevations, ascending to about 1,000 m"  (Standley & Williams, 1974; 24/11 p. 20).

Propagation:  Seed

Native range:  Trinidad and South America to Peru, Bolivia, and Brazil, and now a common tropical weed (Smith, 1988; p. 374).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Federated States of Micronesia Pohnpei Islands	Pohnpei Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 278)
Federated States of Micronesia Pohnpei Islands	Pohnpei Island	introduced invasive	Herrera, Katherine/Lorence, David H./Flynn, Timothy/Balick, Michael J. (2010) (p. 131) Vouchers cited: F.R. Fosberg 58437 (BISH), F.R. Fosberg 58541 (BISH), D.H. Lorence 8051 (BISH, PTBG), L. Stemmermann 2945 (BISH) Naturalized
Fiji Fiji Islands	Viti Levu Island	introduced invasive	Smith, Albert C. (1988) (pp. 373-374) Voucher cited: DA 9624 (L.3998) Sparingly adventive.
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Lorence, David H./Flynn, Timothy W./Wagner, Warren L. (1995) (pp. 51-52) Vouchers cited: M. Kiehn & T. Flynn MK-900917-2/3 (PTBG, WU, US), MK-900917-2/4 (BISH, PRBG, WU), MK-900920-1/2 (PTBG, WU), MK-900920-1/3 (PTBG, WU, US) Naturalized in a sugarcane field.
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Oppenheimer, Hank L. (2004) (p. 17) East Maui. Vouchers cited: Oppenheimer H70203 (BISH, PTBG), Oppenheimer & F. Duvall H60318 (BISH, PTBG)
State of Hawaii Hawaiian Islands	Moloka‘i Island	introduced invasive	Oppenheimer, Hank (2010) (p. 38) Voucher cited: Oppenheimer H110715 (BISH, PTBG)
Palau Palau (Belau ) (main island group)	Babeldaob Island	introduced invasive	Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (p. 102)
Palau Palau (Belau ) (main island group)	Babeldaob Island	introduced invasive	Fosberg, F. R./Canfield, Joan E. (1980) (pp. 199-200) Voucher cited: Canfield 774 (US)
Palau Palau (Belau ) (main island group)	Babeldaob Island	introduced invasive	Space, James C./Lorence, David H./LaRosa, Anne Marie (2009) (p. 65)
Palau Palau (Belau ) (main island group)	Koror (Oreor) Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 278)
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. 99)
Palau Palau (Belau ) (main island group)	Koror (Oreor) Island	introduced invasive	Fosberg, F. R./Canfield, Joan E. (1980) (pp. 199-200) Voucher cited: Otobed PW-10084
Palau Palau (Belau ) (main island group)	Koror (Oreor) Island		Beleu National Museum (Republic of Palau. Koror.) (1977) (voucher ID: BNM 10084) Taxon name on voucher: Spermacoce latifolia Aubl.
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. 99)
Palau Palau (Belau ) (main island group)	Ngerkebesang Island	introduced invasive	Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (p. 99)
Samoa Western Samoa Islands	Upolu Island		Whistler, W. A. (1988) (p. 35)
Samoa Western Samoa Islands	Upolu Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (2002) (voucher ID: PTBG 41471) Taxon name on voucher: Spermacoce cf. latifolia Aublet

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)	Guatemala (Republic of)	native	Standley, Paul C./Williams, Louis O. (1975) (p. 20)
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)
Indonesia Indonesia	Indonesia (Republic of)	introduced invasive	Waterhouse, D. F. (1993) (pp. 63, 76)
Japan Japan	Japan	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 187)
Malaysia Malaysia	Malaysia (country of)	introduced invasive	Waterhouse, D. F. (1993) (pp. 63, 76)
Mexico Mexico	Mexico (United Mexican States)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Singapore Singapore	Singapore (Republic of)	introduced invasive	Waterhouse, D. F. (1993) (pp. 63, 76)
Singapore Singapore	Singapore (Republic of)	introduced invasive	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 81) 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)	Perú (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Thailand Thailand	Thailand (Kingdom of)	introduced invasive	Waterhouse, D. F. (1993) (pp. 63, 76)
Vietnam Vietnam	Vietnam (Socialist Republic of)		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 50)

Control:  If you know of control methods for Spermacoce latifolia, please let us know.