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: Eltham indian fig, dildo, 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 (2013) Thickets, rocks, sandy soils, also cultivated as a hedge; near sea level. S. Guangdong, S. Guangxi, Hainan.
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)

Control:  There is detailed information about identification and control of opuntioid cacti--including Opuntia dillenii (as Opuntia stricta var. dillenii)--in Managing opuntioid cacti in Australia: Best practice control manual for Austrocylindropuntia, Cylindropuntia, and Opuntia species produced by the Western Australian Agriculture Authority.