Desmodium scorpiurus (Sw.) Desv., 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 (2011)
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. (2011) 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. (2011) 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. (2011) 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
China China	China (People's Republic of)	introduced invasive	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2011) "Open dry places; low and middle elevations (sea level to 500 m)".
China China	Hong Kong	introduced	Wu, Te-lin (2001) (p. 143)
Costa Rica Costa Rica	Costa Rica (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Ecuador (Mainland) Ecuador	Ecuador (Republic of) (continental)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Guatemala Guatemala	Guatemala (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Honduras Honduras	Honduras (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Japan Japan	Japan (country)	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 184)
Mexico Mexico	Mexico (United Mexican States)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Nicaragua Nicaragua	Nicaragua (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Panama Panama	Panama (Republic of)	uncertain if native	ILDIS Co-ordinating Centre (2011)
Perú Perú	Perú (Republic of)	uncertain if native	ILDIS Co-ordinating Centre (2011)
Taiwan Taiwan	Taiwan Island	introduced invasive	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2011) "Introduced and naturalized in outhern Taiwan".

Additional information:
Additional online information about Desmodium scorpiurus is available from the Hawaiian Ecosystems at Risk project (HEAR).

Information about Desmodium scorpiurus as a weed (worldwide references) may be available from the Global Compendium of Weeds (GCW).

Taxonomic information about Desmodium scorpiurus may be available from the Germplasm Resources Information Network (GRIN).

References:

Adams, C. D. 1972. Flowering plants of Jamaica. University of the West Indies, Mona, Jamaica. 848 pp.

Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. 2011. Base de données botaniques Nadeaud de l'Herbier de la Polynésie Française (PAP). (online resource).

Fosberg, F. R./Sachet, M.-H. 1987. Flora of Maupiti, Society Islands. The Smithsonian Institution. Atoll Research Bulletin 294:1-70.

Hancock, I. R./Henderson, C. P. 1988. Flora of the Solomon Islands. Research Bulletin No. 7. Ministry of Agriculture and Lands, Honiara. 203 pp.

ILDIS Co-ordinating Centre. 2011. International Legume Database & Information Service. Online searchable database.

McCormack, Gerald. 2011. Cook Islands Biodiversity Database, Version 2007.2. Cook Islands Natural Heritage Trust, Rarotonga.

Merrill, Elmer D. 1923. An enumeration of Philippine flowering plants, vol. 2 [reprint]. Bureau of Printing, Manila. 530 pp.

Mito, Toshikazu/Uesugi, Tetsuro. 2004. Invasive alien species in Japan: the status quo and the new regulation for prevention of their adverse effects. Global Environmental Research 8(2)/2004: 171-191.

Peekel, P. G. [translated by E. E. Henty]. 1984. Flora of the Bismarck Archipelago for naturalists. Office of Forests, Division of Botany, Lae, Papua New Guinea. 638 pp. ISBN 9980-66-000-7.

Smith, Albert C. 1985. Flora Vitiensis nova: a new flora of Fiji. National Tropical Botanical Garden, Lawai, Kauai, Hawaii. Volume 3. 758 pp.

U. S. Government. 2011. Integrated Taxonomic Information System (ITIS) (on-line resource).

U.S. Dept. Agr., Agr. Res. Serv. 2011. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.

Welsh, S. L. 1998. Flora Societensis: A summary revision of the flowering plants of the Society Islands. E.P.S. Inc., Orem, Utah. 420 pp.

Whistler, W. A. 1988. Checklist of the weed flora of western Polynesia. Technical Paper No. 194, South Pacific Commission, Noumea, New Caledonia. 69 pp.

Wu, Te-lin. 2001. Check List of Hong Kong Plants. Hong Kong Herbarium and the South China Institute of Botany. Agriculture, Fisheries and Conservation Department Bulletin 1 (revised). 384 pp.

Zhengyi, Wu/Raven, Peter H./Deyuan, Hong. 2011. Flora of China (online resource).