Desmodium scorpiurus (Sw.) Poir., Fabaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  More information needed, score: 5 (Go to the risk assessment)

Common name(s): [more details]

Chinese: xie wei shan ma huang

English: scorpion ticktrefoil

Habit:  herb

Description:  "Subshrubby, prostrate or scandent to ascending; stem terete to angled, uncinulate-pilosulous; petioles 0.8-1.2 cm long, rachis up to 0.3 cm long; petiolules ca 1 mm long; leaflets mostly narrowly to broadly elliptic, obtuse, appressed-pilose above and below with midrib and chief lateral veins prominent on lower surface, terminal leaflet 1.1-2 cm long, 0.5-1 cm wide, lateral leaflets 1-1.5 cm long, 0.4-0.7 cm wide; stipules 3-4.5 mm long; stipels 1-2 mm long; inflorescence racemose, rachis very finely striate, puberulent; primary bracts up to ca 4 mm long, secondary bracts ca 2 mm long; pedicels puberulent, up to ca 7 mm long; calyx spreading-pilose with central tooth of lower lobe 2 mm long, lateral teeth 1.75 mm long, upper lobe bifid, 2 mm long; standard 3.5 mm long, 1.25 mm wide, wings equaling standard, keel-petals 4 mm long, 1.5 mm wide; loment short-stipitate, usually5-articulate, articles mostly oblong, scarcely if at all narrowed at isthmus, reticulate, uncinulate-pubescent, up to about 5 mm long, 1.5 mm wide"  (Macbride, 1948; p. 433).

"Trailing herb with alternate trifoliate leaves, white (Samoa) or mauve (Tonga) papilionaceous flowers, and jointed pods with cylindrical segments" (Whistler, 1988; p. 24).

Habitat/ecology:  In Fiji, "occasionally naturalized along roadsides near sea level" (Smith, 1985; pp. 190-191).  "Uncommon in disturbed places in coastal areas" (Whistler, 1988; p. 24).  In Jamaica, "rather common, a weed of sandy pastures and roadsides and rocky or stony waste ground, sea level to 1100 ft"  (Adams, 1972; p. 374).

Propagation:  Seed

Native range:  "West Indies and Mexico southward to Peru, now introduced into and adventive in many other areas" (Smith, 1985; pp. 190-191).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Cook Islands Cook Islands	Cook Islands		McCormack, Gerald (2013)
Fiji Fiji Islands	Ovalau Island	introduced invasive	Smith, Albert C. (1985) (pp. 190-191) Voucher cited: DA 17039
Fiji Fiji Islands	Viti Levu Island	introduced invasive	Smith, Albert C. (1985) (pp. 190-191) Vouchers cited: DA 14354, Tothill 108, DA 35, DA 3075, DA 4049, DA 5819, DA 5820, L.11427
French Polynesia Gambier Islands	Mangareva (Gambier) Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) Voucher cited: B. Huguenin s.n. (PAP) Adventice
French Polynesia Society Islands	Maupiti (Maurua) Island		Fosberg, F. R./Sachet, M.-H. (1987) (p. 35) Voucher cited: Fosberg 64846 (US)
French Polynesia Society Islands	Maupiti (Maurua) Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) Adventice
French Polynesia Society Islands	Maupiti (Maurua) Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1985) (voucher ID: PTBG 23242) Taxon name on voucher: Desmodium scorpiurus Desv.
French Polynesia Society Islands	Tahiti Island	introduced invasive	Welsh, S. L. (1998) (p. 150) Vouchers cited: Grant 4887, GRant 5362, Barrau 2006
French Polynesia Society Islands	Tahiti Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) Adventice
Papua New Guinea Bismarck Archipelago	New Britain Island		Peekel, P. G. [translated by E. E. Henty] (1984) (p. 237) In places with volcanic soil.
Philippines Philippine Islands	Philippine Islands	introduced invasive	Merrill, Elmer D. (1923) (p. 289) In open dry thickets, on cliffs, in grasslands, etc., at low and medium altitudes.
Samoa Western Samoa Islands	Western Samoa Islands		Whistler, W. A. (1988) (p. 24)
Solomon Islands Solomon Islands	Solomon Islands	introduced invasive	Hancock, I. R./Henderson, C. P. (1988) (p. 66)
Tonga Ha‘apai Group	Ha‘apai Islands		Whistler, W. A. (1988) (p. 24)
Tonga Vava‘u Group	Vava‘u Island		Whistler, W. A. (1988) (p. 24)

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)	uncertain if native	ILDIS Co-ordinating Centre (2013)
China China	China (People's Republic of)	introduced invasive	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013) "Open dry places; low and middle elevations (sea level to 500 m)".
China China	Hong Kong	introduced	Wu, Te-lin (2001) (p. 143)
Japan Japan	Japan	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 184)
Mexico Mexico	Mexico (United Mexican States)	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)	uncertain if native	ILDIS Co-ordinating Centre (2013)
Taiwan Taiwan Island	Taiwan Island	introduced invasive	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013) "Introduced and naturalized in outhern Taiwan".

Control:  If you know of control methods for Desmodium scorpiurus, please let us know.