Croton hirtus L'Hér., Euphorbiaceae

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Present on Pacific Islands?  no

Primarily a threat at high elevations?  no

Habit:  herb

Description:  "An erect, rather stout annual, commonly 60 cm. high or less, simple or usually branched, the stems and petioles yellow-hispid with long stiff hairs; leaves membranaceous, long-petiolate, rhombic-ovate, often broadly so, 3-7 cm. long, obtuse or acute, rounded or obtuse at the base, coarsely crenate, 3-5-nerved from the base, with 2 long-stipitate glands at the base, stellate-hirsute or in age glabrate; stipules linear, 3-5 mm. long; racemes 1-several at the ends of the branches, 1.5-3 cm. long, the flowers subsessile; bracts linear, with conspicuous stipitate glands; staminate sepals elliptic, acute, stellate-hispidulous, the petals slightly longer; stamens about 10; pistillate sepals unequal, lanceolate or spatulate, 3-4 times as long as the capsule; ovary hirsute; capsule 3-4 mm. long, globose, hirsute; seeds 2.5-3 mm. long, with a small caruncle"  (Standley & Steyermark, 1949; p. 73).

"Erect annual herb to 1 m tall, offensive-smelling.  Stem covered in rigid stellate hairs 2-3 mm long.  Leaves stellate-hairy on both sides, ovate-rhombic, 2-5-7.5 - 1-5 cm, with toothed margins; leaf base glandular, with two stalked glands at petiole apex.  Flowers in terminal racemes 1.5-4 cm long.  Female flowers at base of raceme, green; calyx persistent, unequal-lobed; corolla tiny or absent; ovary stellate bristly, 3-celled.  Male flowers higher in raceme; calyx lobes 5, equal; corolla lobes 5, white; stamens 10 or 11, conspicuous, white.  Fruit a 3-lobed, dehiscent, globular capsule, c. 4 mm diameter.  Seeds 3 mm long, shiny grey-brown, finely and reticulately ribbed, with a tiny white aril."  (Waterhouse & Mitchell, 1998; pp. 41-42).

Habitat/ecology:  In Guatemala (native), "open fields or hillsides, 900 meters or less"  (Standley & Steyermark, 1949; p. 73).  "Sunny to lightly shaded positions. Disturbed land including roadsides, gardens, pastures and cultivated areas; sometimes abundant. 0-700 m altitude." (Waterhouse & Mitchell, 1998; pp. 41-42). In New Guinea, "a weed of roadsides, cultivation and pastures. Reported from the valley of the Laloki River, from altitudes between 100 and 700 m" (Henty & Pritchard, 1975; p. 97).

Propagation:  "Seeds dispersed by ants" (Waterhouse & Mitchell, 1998; pp. 41-42).

Native range:  Tropical America (Waterhouse & Mitchell, 1998; pp. 41-42).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
New Guinea (Indonesia and Papua New Guinea) New Guinea Island	New Guinea Island		Waterhouse, B. M./Mitchell, A. A. (1998) (p. 42) Laloki valley
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)	introduced invasive	Henty, E. E./Pritchard, G. H. (1975) (p. 97) So far reported only from the valley of teh Laloki River, from altitudes between 100 and 700 m.

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Colombia Colombia	Colombia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
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)
El Salvador El Salvador	El Salvador (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Guatemala Guatemala	Guatemala (Republic of)	native	Standley, Paul C./Steyermark, Julian A. (1949) (p. 73)
Honduras Honduras	Honduras (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Indonesia Indonesia	Indonesia (Republic of)		Waterhouse, B. M./Mitchell, A. A. (1998) (p. 42)
Malaysia Malaysia	Malaysia (country of)		Waterhouse, B. M./Mitchell, A. A. (1998) (p. 42)
Nicaragua Nicaragua	Nicaragua (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Panama Panama	Panama (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Singapore Singapore	Singapore (Republic of)		Waterhouse, B. M./Mitchell, A. A. (1998) (p. 42)
Singapore Singapore	Singapore (Republic of)	introduced invasive	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 29) Naturalised
Vietnam Vietnam	Vietnam (Socialist Republic of)		Waterhouse, B. M./Mitchell, A. A. (1998) (p. 42)

Comments:  "A principal weed in Malaysia. Invades orchards, tea plantations, upland rice, tobacco, peanuts and vegetable crops in southeast Asia." (Waterhouse & Mitchell, 1998; pp. 41-42).

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

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

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

References:

Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. 2009. A checklist of the total vascular plant flora of Singapore: native, naturalised and cultivated species. Raffles Museum of Biodiversity Research, National University of Singapore. 273 pp.

Henty, E. E./Pritchard, G. H. 1975. Weeds of New Guinea and their control. 2nd edition. Department of Forests, Division of Botany, Botany Bull. No. 7. Lae, Papua New Guinea. 180 pp.

Standley, Paul C./Steyermark, Julian A. 1949. Flora of Guatemala. Fieldiana: Botany. Vol. 24, Part VI. Chicago Natural History Museum. 440 pp.

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

Waterhouse, B. M./Mitchell, A. A. 1998. Northern Australia Quarantine Strategy: weeds target list. Second edition. Australian Quarantine & Inspection Service, Miscellaneous Publication No. 6/98. 110 pp.