Spermacoce exilis (L. O. Williams) C. D. Adams, Rubiaceae

Click on an image for links to BIGGER PICTURES

Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Borreria repens DC.; Spermacoce mauritiana Gideon

Common name(s): [more details]

Chinese: er e feng hua cao

English: Pacific bradleaf false buttonweed, Pacific false buttonweed

Habit:  herb

Description:  "Annual herbs; stems decumbent, 0.2-4 dm long, usually many-branched, sparsely to densely crisped puberulent in lines on the angles.  Leaves opposite, elliptic to elliptic-lanceolate, 0.4-3.5 cm long, 0.2-1.6 cm wide, scabridulous near margins and usually crisped puberulent along principal veins on lower surface, apex acute to rounded, base cuneate, petioles 0-5 mm long, stipules ca. 2 mm long, with ca. 7 setae 1-3 mm long.  Flowers few in axillary, dense, sessile clusters, stipule-derived bracteoles with setae 1.8-2 mm long; hypanthium ca. 0.5 mm long; calyx lobes 2 (-4), 0.6-0.8 mm long, ciliate; corolla white, 0.6-0.7 mm long.  Fruit oblong, compressed, ca. 1 mm long, finely transversely wrinkled, puberulent, dehiscent. Seeds chestnut brown or yellowish brown, oblong-ellipsoid, 0.7-1 mm long, minutely reticulate, the areolae transversely wider than high" (Wagner et al., 1999; pp. 1173-1174).

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:  "Disturbed areas in villages, tracksides.  Prefers moist shaded conditions but will grow in sunny sites." (Waterhouse & Mitchell, 1998; pp. 89-90).

In Hawai‘i, "recently naturalized in relatively dry areas" (Wagner et al., 1999; pp. 1173-1174).  In Fiji, "an occasional weed in villages and gardens between sea level and 200 m" (Smith, 1988; p. 373).  In Samoa, "uncommon in lawns and other sunny, disturbed places" (Whistler, 1988; p. 35).  In Papua New Guinea, "a weed of lawns and gardens, particularly in damp, partly shaded situations"  (Henty & Pritchard, 1975; p. 144).

Propagation:  "Seeds dispersed by water, human activities" (Waterhouse & Mitchell, 1998; pp. 89-90).

Native range:  "Native to Africa and Malesia, now widely naturalized in the Pacific Basin and Central and South America" (Wagner et al., 1999; pp. 1173-1174).  "Now a pantropical weedy plant, but probably of American origin and an early introduction into the Old World tropics, where it gives the appearance of being indigenous in parts of Africa, Indian Ocean islands, southeastern Asia, and Malesia" (Smith, 1988; p. 373).

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 Kosrae Island	Kosrae Island	introduced invasive	Lorence, David H./Flynn, Timothy (2010) (p. 24) Voucher cited: Lorence 7855 (PTBG) Naturalized
Federated States of Micronesia Kosrae Island	Kosrae Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1996) (voucher ID: PTBG 21110) Taxon name on voucher: Spermacoce exilis (L. O. Williams) C. Adams
Federated States of Micronesia Pohnpei Islands	Nukuoro Atoll		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (2005) (voucher ID: PTBG 46117) Taxon name on voucher: Spermacoce exilis
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		Glassman, S. F. (1952) (p. 91) Voucher cited: Glassman 2583 (US)
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: S.F. Glassman 2583 (BISH), E.Y. Hosaka 3541 (BISH), T. Hosokawa 5572 (BISH), D.H. Lorence 7902 (BISH), D.H. Lorence 8047 (PBG), D.H. Lorence Naturalized
Federated States of Micronesia Pohnpei Islands	Pohnpei Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1996) (voucher ID: PTBG 21119) Taxon name on voucher: Spermacoce exilis (L. O. Williams) C. Adams
Federated States of Micronesia Pohnpei Islands	Pohnpei Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1997) (voucher ID: PTBG 29342) Taxon name on voucher: Spermacoce exilis (M. Martens & Galeoti) Hemsl.
Federated States of Micronesia Yap Islands	Yap (Waqab) Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 278)
Fiji Fiji Islands	Kanathea Island	introduced invasive	Smith, Albert C. (1988) (p. 373) Voucher cited: Bryan 571
Fiji Fiji Islands	Lakemba Island	introduced invasive	Smith, Albert C. (1988) (p. 373) Voucher cited: Garnock-Jones 908
Fiji Fiji Islands	Ovalau Island	introduced invasive	Smith, Albert C. (1988) (p. 373) Voucher cited: Smith 7473
Fiji Fiji Islands	Taveuni Island	introduced invasive	Smith, Albert C. (1988) (p. 373) Voucher cited: Gillespie 4400.3
Fiji Fiji Islands	Vanua Levu Island	introduced invasive	Smith, Albert C. (1988) (p. 373) Vouchers cited: DA 10470, DA 10767
Fiji Fiji Islands	Vanua Mbalavu Island	introduced invasive	Smith, Albert C. (1988) (p. 373) Voucher cited: Garnock-Jones 983
Fiji Fiji Islands	Viti Levu Island	introduced invasive	Smith, Albert C. (1988) (p. 373) Voucher cited: Greenwood 151, DA 9738, Smith 4319, DA 10416, DA 10180, Smith 9444, DA 9521, DA 10006, Gillespie 3424, DA 10622, Meebold 16690
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 1173-1174)
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive	Lorence, David H./Flynn, Timothy W./Wagner, Warren L. (1995) (p. 51) Vouchers cited: D. Lorence et al. 6571 (PTBG), D. Lorence & T. Flynn 6665A (PTBG), W.L. Wagner & S. Mill Arey 6429 (US), D. Lorence et al. 6575 (PTBG)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (pp. 1173-1174)
Palau Palau (Belau ) (main island group)	Babeldaob Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 278)
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	Lorence, David H./Flynn, Tim (2010) (p. 40) Voucher cited: Lorence 8224 (PTBG)
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)	introduced invasive	Waterhouse, B. M./Mitchell, A. A. (1998) (pp. 89-90)
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)	invasive	Henty, E. E./Pritchard, G. H. (1975) (p. 144) As Borreria repens DC. At low altitudes, well-established in a few areas but apparently not widespread.
Philippines Philippine Islands	Philippine Islands	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Samoa Western Samoa Islands	Western Samoa Islands		Whistler, W. A. (1988) (p. 35)
Solomon Islands Solomon Islands	Solomon Islands	introduced invasive	Smith, Albert C. (1988) (p. 373)

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	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) Naturalized in disturbed humid sites at low elevations. Hainan, Hong Kong.
China China	Hong Kong	native	Wu, Te-lin (2001) (p. 261) As Borreria repens DC. In open field or on grassland.
Indonesia Indonesia	Indonesia (Republic of)	introduced invasive	Waterhouse, B. M./Mitchell, A. A. (1998) (pp. 89-90)
Indonesia Indonesia	Indonesia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Malaysia Malaysia	Malaysia (country 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)
Singapore Singapore	Singapore (Republic of)	uncertain if introduced invasive	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 81) Weed of uncertain origin
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)
South America (Pacific rim) South America (Pacific rim)	Perú (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Taiwan Taiwan Island	Taiwan Island	introduced invasive	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013) Naturalized in disturbed humid sites at low elevations.
Vietnam Vietnam	Vietnam (Socialist Republic of)		Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013)

Indian Ocean
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia (Indian Ocean offshore islands) Christmas Island Group	Christmas Island	introduced invasive	Waterhouse, B. M./Mitchell, A. A. (1998) (pp. 89-90)
Mauritius Mautitius Islands (Mauritius and Rodrigues)	Mauritius Island	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)

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