Spermacoce ovalifolia (M.Martens & Galeotti) Hemsl., Rubiaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Borreria ovalifolia M. Martens & Galeotti; Spermacoce ernstii Fosberg & D. Powell

Common name(s): [more details]

English: broadleaf false buttonweed

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: "Annual herbs to 40 cm tall, often branched near the base and with few distal branches, leafy stems 0.5-2 mm thick, with 4 longitudinal ribs ca. 0.2 mm high, glabrous or minutely puberulent at the nodes; stipule sheath 0.5-3 mm high, often obscured by the inflorescences, with 3-11 awns 1-5 mm long.  Leaves opposite (occasionally pseudoverticillate) with 2-4 smaller axillary leaves, petioles 0-5 mm long, with lateral margins continuous with the leaf margins; leaf blades 6-48 mm long, 2-16 mm broad, elliptic to narrowly elliptic, elliptic-lanceolate or ovate-elliptic, apex acute, base acute to cuneate, drying membranaceous, brownish or dark green above, glabrous or with a few scabrous hairs above, subglabrous or with minute (0.1-0.2 mm) stiff hairs beneath, scabrous on the edges, 2§ veins 2-5/side.  Inflorescences axillary and verticillate or terminal and subtended by 2-6 leaves, 2-4 mm high, 3-6 mm broad, with few (5-12) flowers.  Flowers with 4 calyx lobes 0.6-1.1 mm long, 0.1-0.2 mm broad, linear-aculeate, persisting; corolla minute.  Fruits ca. 2 mm long and 2 mm broad when opened, body of the capsule ca. 1.5 mm long, glabrous externally or minutely (o.05-0.1 mm) hispid distally; seeds (1.3-) 1.5-1.8 mm long, 0..8-0.9 mm broad, very finely reticulate (x 10) and minutely pitted (x 40), dark reddish brown" (Berger & Taylor, 1993; pp. 317-318).

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 Costa Rica, "weedy plants of open sites in evergreen and partly deciduous areas of the Meseta Central, 900-1400 m elevation" (Berger & Taylor, 1993; pp. 317-318).

Propagation:  Seed

Native range:  "The species ranges widely, from the southern United States to South America, the West Indies, and the Old World" (Berger & Taylor, 1993; pp. 317-318).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
American Samoa Manu‘a Islands	Ofu Island	introduced	Ragone, Diane/Lorence, David H. (2003) (p. 54)
American Samoa Manu‘a Islands	Ofu Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (2001) (voucher ID: PTBG 34837) Taxon name on voucher: Spermacoce ovalifolia (M. Martens & Galeotti) Hemsl.
American Samoa Manu‘a Islands	Ofu Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1991) (voucher ID: PTBG 11071) Taxon name on voucher: Spermacoce ovalifolia
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Rota Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 278)
Commonwealth of the Northern Mariana Islands (US) Northern Mariana Islands	Tinian Island	introduced	Raulerson, L. (2006) (p. 66)
Commonwealth of the Northern Mariana Islands (US) Saipan	Saipan Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 278)
Federated States of Micronesia Chuuk Islands	Puluwat (Pwonowót) Atoll	introduced invasive	Manner, H. I./Mallon, E. (1989) (p. 60) Voucher cited: Manner & Mallon 208 (GUAM) Rare
Federated States of Micronesia Chuuk Islands	Weno (Moen) Island	introduced	Fosberg, F. R./Sachet, M.-H./Oliver, R. L. (1993) (p. 120) Voucher cited: Grimm 15 (US)
Federated States of Micronesia Kosrae Island	Kosrae Island	introduced invasive	Lorence, David H./Flynn, Timothy (2010) (p. 24) Voucher ctied: Lorence 7872 (PTBG) Naturalized
Federated States of Micronesia Kosrae Island	Kosrae Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1996) (voucher ID: PTBG 21062) Taxon name on voucher: Spermacoce ovalifolia (M. Martens & Galeoti) Hemsl.
Federated States of Micronesia Kosrae Island	Kosrae Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1997) (voucher ID: PTBG 24876) Taxon name on voucher: Spermacoce ovalifolia (M. Martens & Galeoti) Hemsl.
Federated States of Micronesia Kosrae Island	Kosrae Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (2005) (voucher ID: PTBG 44903) Taxon name on voucher: Spermacoce ovalifolia
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: M.J. Balick 4092 (NY, PTBG), N.L.H. Krauss 1891b (BISH), D.H. Lorence 8058 (PTBG), D.H. Lorence 8098 (PTBG), D.H. Lorence 9552 (COM, NY, PTBG, US), D.H. Lorence 9572 (COM, NY, PTBG, US), P. Raynor 166 (NY, PTBG) Naturalized
Federated States of Micronesia Pohnpei Islands	Pohnpei Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1997) (voucher ID: PTBG 28109) Taxon name on voucher: Spermacoce ovalifolia (L. O. Williams) C. D. Adams
Federated States of Micronesia Pohnpei Islands	Pohnpei Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1997) (voucher ID: PTBG 28627) Taxon name on voucher: Spermacoce ovalifolia (M. Martens & Galeoti) Hemsl.
Federated States of Micronesia Pohnpei Islands	Pohnpei Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (2000) (voucher ID: PTBG 43692) Taxon name on voucher: Spermacoce ovalifolia
Federated States of Micronesia Pohnpei Islands	Pohnpei Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (2003) (voucher ID: PTBG 43746) Taxon name on voucher: Spermacoce ovalifolia
Federated States of Micronesia Yap Islands	Yap (Waqab) Island		Swarbrick, John T. (1997) (p. 97)
Guam Guam Island	Guam Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 278)
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive	Lorence, David H./Flynn, Timothy W./Wagner, Warren L. (1995) (p. 52) Vouchers cited: T. Flynn et al. 3910 (PTBG, US), D. Lorence & T. Flynn 6673 (PTBG), W.L. Wagner et al. 5976 (BISH, PTBG), W.L. Wagner & S. Mill Arey 6390 (US).
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Oppenheimer, Hank L. (2003) (pp. 23-24) As Spermacoce prostrata Aubl. Vouchers cited: (West Maui) Oppenheimer H20127 (BISH) (All plants at this location destroyed); (East Maui) Oppenheimer H89929 (PTBG), Starr & Martz 010508-3 (BISH). Wagner et al, 2012, p. 66, lists as Spermacoce ovalifolia (M. Martens & Galeotti) Hemsl.
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Wagner, Warren L./Shannon, Robynn K./Herbst, Derral R. (1997) (p. 61) Voucher cited: Imada et al. 94-5 (BISH)
Kiribati Tungaru (Gilbert) Islands	Abemama Atoll	introduced invasive	Space, James C./Imada, Clyde T. (2004) (p. 76) Voucher: Imada 2003-138 (BISH 697750)
Kiribati Tungaru (Gilbert) Islands	Butaritari Atoll	introduced invasive	Space, James C./Imada, Clyde T. (2004) (p. 78) Voucher: Imada 2003-53 (BISH 697668)
Kiribati Tungaru (Gilbert) Islands	Tarawa Atoll	introduced invasive	Space, James C./Imada, Clyde T. (2004) (p. 75) Voucher: Imada 2003-42 (BISH 697657)
Kiribati Tungaru (Gilbert) Islands	Tarawa Atoll	introduced	Fosberg, F. R./Sachet, M.-H./Oliver, R. L. (1993) (p. 120) Voucher cited: Raulerson 3801 (US)
Marshall Islands Ratak Chain	Arno Atoll	introduced invasive	Vander Velde, Nancy/Vander Velde, Brian (2007) (p. 11) "Common to abundant; in lawns and ruderal areas".
Marshall Islands Ratak Chain	Majuro (Mãjro) Atoll		Wagner, W. L./ Herbst, D. R./Weitzman, A./Lorence, D.H. (2013)
Marshall Islands Ratak Chain	Maloelap Atoll		Imada, Clyde (2006)
Marshall Islands Ratak Chain	Mili (Mile) Atoll	introduced invasive	Vander Velde, Nancy/Vander Velde, Brian (2010) (p. A20) As Spermacoce ernstii Fosb. & Powell. Common; along pathways, on runway, near homes, ruderal areas.
Palau Kayangel Atoll	Kayangel Islet	introduced invasive	Miles, Joel (2015) (p. 2) ref cites other taxa as "Cultivated," but not this one, so implication is that this taxon was found in a non-cultivated situation (PT@PhilipT.com/20170602)
Palau Kayangel Atoll	Ngeriungs Islet	introduced invasive	Miles, Joel (2015)
Palau Palau (Belau ) (main island group)	Angaur (Ngeaur) Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 278)
Palau Palau (Belau ) (main island group)	Babeldaob Island		Raulerson, L./Rinehart, A. F./Falanruw, M. C. (1996) (p. 34)
Palau Palau (Belau ) (main island group)	Babeldaob Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1998) (voucher ID: PTBG 28059) Taxon name on voucher: Spermacoce ovalifolia (M. Martens & Galeoti) Hemsl.
Palau Palau (Belau ) (main island group)	Kayangel (Ngcheangel) Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 278)
Palau Palau (Belau ) (main island group)	Kayangel (Ngcheangel) Island	introduced invasive	Space, James C./Lorence, David H./LaRosa, Anne Marie (2009) (p. 65) Voucher: Lorence 9779B (PTBG, BNM, NY)
Palau Palau (Belau ) (main island group)	Kayangel (Ngcheangel) Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (2008) (voucher ID: PTBG 72) Taxon name on voucher: Spermacoce ovalifolia
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)	Ngercheu Island	introduced invasive	Space, James C./Lorence, David H./LaRosa, Anne Marie (2009) (p. 65) Carp Resort
Palau Palau (Belau ) (main island group)	Ngerkebesang Island	introduced invasive	Space, James C./Lorence, David H./LaRosa, Anne Marie (2009) (p. 65) Voucher: Lorence 9722 (PTBG, BNM, NY, US)
Palau Palau (Belau ) (main island group)	Ngerkebesang Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (2008) (voucher ID: PTBG 15) Taxon name on voucher: Spermacoce ovalifolia
Palau Palau (Belau ) (main island group)	Peleliu (Beliliou) Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 278)
Palau Palau (Belau ) (main island group)	Peleliu (Beliliou) Island	introduced invasive	Space, James C./Lorence, David H./LaRosa, Anne Marie (2009) (p. 65) Voucher: Lorence 9752 (PTBG, BNM, NY, US)
Palau Palau (Belau ) (main island group)	Peleliu (Beliliou) Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (2008) (voucher ID: PTBG 44) Taxon name on voucher: Spermacoce ovalifolia
Palau Rock Islands (Chelbacheb)	Ngerchong Island	introduced invasive	Space, James C./Lorence, David H./LaRosa, Anne Marie (2009) (p. 65)
Palau Sonsorol Group	Sonsorol Island		Wagner, W. L./ Herbst, D. R./Weitzman, A./Lorence, D.H. (2013)

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)	Nicaragua (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Mexico Mexico	Mexico (United Mexican States)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
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)

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