Euphorbia helioscopia (Retz.) C. E. Hubb., Euphorbiaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

Chinese: ze qi

English: sun spurge, wolf's-milk

French: euphorbe reveil matin, tithymale

Japanese: todaigusa

Spanish: lecherina, lecheruela, lechetrezna comun, mamona, pichoa, pichoga

Habit:  herb

Description:  "An annual monoecious herb with milky sap throughout; branched taproot up to 80 cm long; stems simple or branched at base, yellowish-green or sometimes purplish, glabrous, erect or ascending 15 to 60 cm tall, bearing terminal flower clusters; leaves alternate, 1 to 3 cm long, 1 to 1.5 cm wide, terminal leaves often in whorls of 5, simple, sessile, serrulate, obovate or rounded at apex, margins entire or finely toothed at apex; inflorescence composed of 5 umbel-like cyathia (cup-like receptacles, each containing a flowering group), subtended by a whorl of 5 leaves, smaller than stem leaves and not as narrow at base; each branch divides into 3 branches of second order and then 2 of third order with terminal flower cluster; involucre urn-shaped, with 4 rounded glands; flowers without petals, unisexual, flowering group with a single, central pistillate flower with a gynoecium: a long stalk with 3 styles and 3-celled ovary that extends beyond involucre after anthesis; surrounded by 10 to 12 simple staminate flowers each consisting of single stamen with small bract at base; fruit a dry, dehiscent schizocarp 4 to 5 mm in diameter with 3 carpels; at maturity carpels open violently; seed obovate to ovate in outline, circular in cross-section, 2 mm long, 1.5 mm wide, dark brown to orange-brown, with surface roughened by raised fine-meshed network; hilum kidney shaped, white and very conspicuous.  This species is recognized by its milky sap throughout, flowers in terminal umbels of branched cymes, each surrounded by a whorl of five leaves, and the sharply reticulate seed surface"  (Holm et al., 1997; p. 353).

"Annual, stems ascending, 0.5-6 dm high; leaves all obovate and very rounded or retuse at the end, finely serrate, smooth or a little hairy, those of the stem cuncate; umbel divided into usually 5 4 rays, then into 3, or at length simply forked; floral leaves narrowed to base; glands orbicular or elliptical, yellow, stalked; capsule smooth and even; seeds with coarse honeycomb-like reticulations" (Fernald, 1970; pp. 967-968).

Habitat/ecology:  Waste places and dry open soil (Fernald, 1970; pp. 967-968). In New Caledonia, "mauvaise herbe peu commune des jardins" (MacKee, 1994; p. 51).  "In Chile this species grows in the following environmental conditions:  Medium altitude up to the timber line; low altitude, interior valleys; coastal mountains, 500-2000 m; coastal areas, 0-500 m.  The plant grows in water or it has its roots within a permanent water course, this corresponds to marshes, bogs, water courses, lake and river shores; humid areas, with almost constant rainfall, short dry periods are possible (generally not longer than 1 month).  Fully exposed to the sun, level areas or slopes facing north; some shadow, some protection against direct sunlight, some shadow from vegetation, filtering about 20-40% of light"  (Chileflora).

Propagation:  Seed

Native range:  Europe, temperate and tropical Asia, northern Africa; 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
Chile (offshore islands) Juan Fernández Islands	Isla Más a Tierra (Robinson Crusoe Island)	introduced	Cuevas, Jaime G./Marticorena, Alicia/Cavieres, Lohengrin A. (2004) (p. 535) Voucher cited: CONC 158065, JF 186
Chile (offshore islands) Juan Fernández Islands	Isla Más a Tierra (Robinson Crusoe Island)	introduced invasive cultivated	Atkinson, Rachel/Sawyer, John (2011)
Chile (offshore islands) Juan Fernández Islands	Isla Más a Tierra (Robinson Crusoe Island)	introduced invasive cultivated	Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (p. 553)
New Caledonia New Caledonia Archipelago	Île Grande Terre	introduced invasive	Tassin, Jacques (2005)
New Caledonia New Caledonia Archipelago	Île Grande Terre	introduced invasive	MacKee, H. S. (1994) (p. 51) Voucher cited: MacKee 40818

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)	New South Wales	introduced invasive	Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 351)
Australia Australia (continental)	Queensland	introduced invasive	Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 351)
China China	China (People's Republic of)	native	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013) Fields, roadsides, scrub, margins of mixed forests. Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hainan, Hebei, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Liaoning, Ningxia, Qinghai, Shaanxi, Shandong, Shanxi, Sichuan, Xinjiang, Yunnan, Zhejiang.
China China	Hong Kong	introduced cultivated	Wu, Te-lin (2001) (p. 180)
Japan Japan	Japan	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
North Korea North Korea	North Korea (Democratic People's Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
South Korea South Korea	South Korea (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 628) "Common in gardens, waste places and crops, occasional in riverbeds".
South America (Pacific rim) South America (Pacific rim)	Chile (Republic of)	introduced invasive	Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 351)
Taiwan Taiwan Island	Taiwan Island	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Vietnam Vietnam	Vietnam (Socialist Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)

Control:  If you know of control methods for Euphorbia helioscopia, please let us know.