Opuntia dillenii (Ker Gawl.) Haw., Cactaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

Chinese: xian ren zhang

English: dildo, Eltham indian fig, sweet prickly-pear

Habit:  cactus

Description:  "Low spreading plants often forming massive and extensive clumps, rarely completely erect and branched or exceeding 2 m tall; joints obovate to oblong, 17-40 x 12-20 cm, margin and surface usually undulate, bluish green and glaucous, not readily detached; areoles slightly elevated, spines stout, 2 to 10, curved, yellow often banded with brown, flattened on one side at base, apex not noticeably retrorse-barbed, glochids numerous, yellow, wool white or brown. Leaves subulate, recurved, to 5 mm long. Flowers mostly marginal, rarely found on face of joint; perianth bright yellow, petals spreading, 4-5 cm long; ovary obovoid, 3 cm long in flower, becoming 7-9 cm long in fruit, narrowed at base. Mature fruits obovoid, bright red-purple to pinkish red, usually extremely juicy, areoles with slender spines or spineless, glochids present; seeds white" (Howard, 1989; pp. 412-413).

Habitat/ecology:  "Grass- and heathland, dry forests, shrubland, rock outcrops.  The cactus forms dense and spiny thickets that crowd out native plants and affect wildlife.  Scattered clumps expand laterally and may lead to thickets that cover large areas"  (Weber, 2003; p. 289).

In New Caledonia, "cité par Guillaumin (1962) comme trè envahissant" (MacKee, 1994; p. 25).  In Jamaica, "sandy upper beaches, salina margins, in arid scrub thickets and on some of the cays" (Adams, 1972; p. 274).

Propagation:  "The joints of this cactus dislodge and root easily.  They are carried by water streams and by animals.  Seeds are dispersed by animals feeding on the fruits"  (Weber, 2003; p. 289).

Native range:  Southern United States, Greater Antilles (Howard, 1989; pp. 412-413).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Ecuador (Galápagos Islands) Floreana Group	Floreana Island	introduced cultivated	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Isabela Group	Isabela Island	introduced cultivated	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Isabela Group	Volcán Sierra Negra, Isabela Island	introduced cultivated	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) San Cristóbal Group	San Cristóbal Island	introduced cultivated	Charles Darwin Foundation (2008)
Ecuador (Galápagos Islands) Santa Cruz Group	Santa Cruz Island	introduced cultivated	Charles Darwin Foundation (2008)
New Caledonia New Caledonia	New Caledonia Islands		Swarbrick, John T. (1997) (p. 94)

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 cultivated	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2011) Thickets, rocks, sandy soils, also cultivated as a hedge; near sea level. S. Guangdong, S. Guangxi, Hainan.
Ecuador (Mainland) Ecuador	Ecuador (Republic of) (continental)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Mexico Mexico	Mexico (United Mexican States)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)

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

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

Taxonomic information about Opuntia dillenii 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.

Charles Darwin Foundation. 2008. Database inventory of introduced plant species in the rural and urban zones of Galapagos. Charles Darwin Foundation, Galapagos, Ecuador.

Charles Darwin Research Station. 2005. CDRS Herbarium records.

Howard, Richard A. 1989. Flora of the Lesser Antilles: Leeward and Windward Islands. Vol. 5 Dicotyledoneae-Part 2 Arnold Arboretum, Harvard University. 604 pp.

MacKee, H. S. 1994. Catalogue des plantes introduites et cultivées en Nouvelle-Calédonie. Muséum National d'Histoire Naturelle, Paris, 164 p.

Swarbrick, John T. 1997. Weeds of the Pacific Islands. Technical paper no. 209. South Pacific Commission, Noumea, New Caledonia. 124 pp.

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

Weber, Ewald. 2003. Invasive plants of the World. CABI Publishing, CAB International, Wallingford, UK. 548 pp.

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