Trifolium dubium Sibth., Fabaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Trifolium minus Sm.; Trifolium parviflorum Bunge ex Nyman

Common name(s): [more details]

Chinese: dun ye che zhou cao

English: hop clover, lesser trefoil, low hop clover, shamrock, small hop clover, suckling clover, yellow clover, yellow suckling clover

French: trèfle douteux

Habit:  herb

Description:  "Annual herbs, glabrous to sparsely pubescent. Stems erect to decumbent, (5-) 10-30 (-40) cm. Leaves pinnately 3-foliolate; stipules obliquely ovate, 4-8 mm, base rounded, margins finely dentate, apex acute; petiole shorter than or equal to leaflets; terminal petiolule longer than lateral petioles; leaflets obovate, 5-10(-12) x 3-8 mm, veins 6-8 pairs, base cuneate, margins entire proximally, obscurely serrulate distally, apex rounded or emarginate. Flowers 5-15, in axillary heads; peduncle 0.5-3 (-4) cm, pubescent; pedicels less than 1 mm, after flowering pendulous. Calyx ca. 2 mm, veins 5. Corolla pale yellow, turning brown, 3-4 mm; standard narrowly boat-shaped, smooth, apex acute. Legume oblong, 1.5-2 mm, shortly beaked; stipe ca. 1 mm. Seed 1, pale brown, globose"  (Flora of China online).

Habitat/ecology:  In Hawai‘i, "naturalized in pastures, along streambanks and roadsides, also in subalpine shrubland, 910-2,200 m"  (Wagner et al.,  1999; p. 712).  In New Zealand, "growing in a wide range of habitats, especially waste places, pasture, lawns, gardens, and cultivated land"  (Webb et al., 1988; p. 685).

Propagation:  Seed

Native range:  Europe, northern Africa, western Asia; naturalized elsewhere (GRIN).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia (Pacific offshore islands) Lord Howe Island	Lord Howe Island	introduced invasive	Orchard, Anthony E., ed. (1994) "Naturalised in waste places, pastures, etc.".
Australia (Pacific offshore islands) Norfolk Islands	Norfolk Island	introduced invasive	Orchard, Anthony E., ed. (1994) "Naturalised in waste places, pastures, etc.".
Chile (offshore islands) Juan Fernández Islands	Isla Más Afuera (Alejandro Selkirk Island)	introduced invasive	Atkinson, Rachel/Sawyer, John (2011)
Chile (offshore islands) Juan Fernández Islands	Isla Más Afuera (Alejandro Selkirk Island)	introduced invasive	Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (p. 558)
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 712) Voucher cited: Forbes 713.H (BISH)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Lorence, David H./Flynn, Timothy W./Wagner, Warren L. (1995) (p. 37) Vouchers cited: T. Flynn & S. Perlman 3899 (BISH, PTBG, US), T. Flynn et al. 3259 (PTBG)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 712) East Maui
New Zealand (offshore islands) Kermadec Islands	Kermadec Islands	introduced invasive	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 685)
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)	introduced	ILDIS Co-ordinating Centre (2011)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia Australia (continental)	Australia (continental)	introduced	ILDIS Co-ordinating Centre (2011) Australian Capital Territory, South Australia, Tasmania, Victoria, Western Australia
Australia Australia (continental)	New South Wales	introduced invasive	National Herbarium of New South Wales (2011) "A common lawn weed".
Australia Australia (continental)	Queensland	introduced invasive	National Herbarium of New South Wales (2011) "A common lawn weed".
Canada Province of British Columbia	Canada (British Columbia)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2011)
Canada Canada	Canada (country)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2011)
Chile (continental) Chile	Chile (Republic of)	introduced	ILDIS Co-ordinating Centre (2011)
China China	China (People's Republic of)	introduced invasive cultivated	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2011) Cultivated, escaped, and naturalized. Jiangsu, Shaanxi.
Colombia Colombia	Colombia (Republic of)	introduced	ILDIS Co-ordinating Centre (2011)
Costa Rica Costa Rica	Costa Rica (Republic of)	introduced	ILDIS Co-ordinating Centre (2011)
Indonesia Indonesia	Indonesia (Republic of)	introduced	ILDIS Co-ordinating Centre (2011)
Japan Japan	Japan (country)	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 185)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 685)
Panama Panama	Panama (Republic of)	introduced	ILDIS Co-ordinating Centre (2011)
Perú Perú	Perú (Republic of)	introduced	ILDIS Co-ordinating Centre (2011)
Taiwan Taiwan	Taiwan Island	introduced	ILDIS Co-ordinating Centre (2011)
Taiwan Taiwan	Taiwan Island	introduced invasive cultivated	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2011) Cultivated, escaped, and naturalized.
United States (west coast) United States (west coast states)	USA (Oregon)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2011)
United States (west coast) United States (west coast states)	USA (California)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2011)
United States (west coast) United States (west coast states)	USA (Washington)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2011)

Indian Ocean
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
La Réunion (France) La Réunion Island	La Réunion Island	introduced	ILDIS Co-ordinating Centre (2011)

Also reported from
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
United States (continental except west coast) United States (other states)	United States (other states)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2011)

Additional information:
Invasive species profile from the Global Invasive Species Database.

Additional online information about Trifolium dubium is available from the Hawaiian Ecosystems at Risk project (HEAR).

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

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

References:

Atkinson, Rachel/Sawyer, John. 2011. Naturalized species in the Juan Fernández Archipelago, Chile. Unpublished spreadsheet.

Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido. 2006. Nouveau catalogue de la flore vaculaire de l'archipel Juan Fernández (Chile) [Nuevo catálogo de la flora vacular del Archipélago Juan Fernández (Chile)]. Acta Bot. Gallica 153(4):399-587.

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

Lorence, David H./Flynn, Timothy W./Wagner, Warren L. 1995. Contributions to the flora of Hawai‘i. III. New additions, range extensions, and rediscoveries of flowering plants. In: Evenhuis, Neal L. and Miller, Scott, E., eds. Records of the Hawaii Biological Survey for 1994. Part 1: Articles. Bishop Museum Occasional Papers. 41:19-58.

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.

National Herbarium of New South Wales. 2011. PlantNet: New South Wales Flora online. The Plant Information Network System of the Botanic Gardens Trust Version 2.0. Online resource.

Orchard, Anthony E., ed. 1994. Flora of Australia. Vol. 49, Oceanic islands 1. Australian Government Publishing Service, Canberra.

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.

U.S. Dept. Agr., Nat. Res. Cons. Serv. 2011. The PLANTS Database. National Plant Data Center, Baton Rouge, LA 70874-4490 USA.

Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. 1999. Manual of the flowering plants of Hawaii. Revised edition. Bernice P. Bishop Museum special publication. University of Hawai‘i Press/Bishop Museum Press, Honolulu. 1919 pp. (two volumes).

Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. 1988. Flora of New Zealand, Volume IV: Naturalised pteridophytes, gymnosperms, dicotyledons. Botany Division, DSIR, Christchurch. 1365 pp.

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