Clausena excavata Burm. f., Rutaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

Chinese: jia huang pi

English: clausena

Habit:  tree

Description:  "A slender tree to 10 m tall. Twigs finely hairy. Leaves pinnate, to 60 cm long, with 10-15 pairs of dark green narrowly oval oblique leaflets 3.5-7 cm long with pointed tips. Leaflets have a characteristic curry-like smell when crushed. Small white flowers occur in terminal clusters, followed by translucent pink berries 7-10 mm across, each containing 1-2 seeds." (Swarbrick, 1997; p. 29-30).

Habitat/ecology:  Establishes dense stands along roads and in disturbed areas (Swarbrick, 1997; p. 29-30).

Propagation:  Seeds distributed by birds (Swarbrick, 1997; p. 29-30).

Native range:  India, southeast Asia, Philippines (Swarbrick, 1997; p. 29-30).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Philippines Philippine Islands	Philippine Islands	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Philippines Philippine Islands	Philippine Islands		Merrill, Elmer D. (1923) (p. 337) In thickets and old clearings at low altitudes.

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)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Indonesia Indonesia	Indonesia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Malaysia Malaysia	Malaysia (country of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Singapore Singapore	Singapore (Republic of)	native	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 26) Common
Taiwan Taiwan	Taiwan Island	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Thailand Thailand	Thailand (Kingdom of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Vietnam Vietnam	Vietnam (Socialist Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)

Indian Ocean
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia (Indian Ocean offshore islands) Christmas Island Group	Christmas Island	introduced invasive	Swarbrick, J. T. (1997) (pp. 29-30, 109)

Comments:  A problem on Christmas Island (Indian Ocean) (Swarbrick, 1997; p. 29-30). Reported to be under cultivation in Hawai‘i (Wagner et al., 1999; p. 1175).

Control: 

Chemical: Seedlings can be sprayed with a systemic herbicide. Larger trees can be cut and the stump treated with glyphosate to prevent resprouting. Basal bark treatment or stem injection may also be effective.

"Pending the results of field trials seedlings should be sprayed with 2% Roundup plus Pulse in clean water, and saplings and trees cut either cut stump treated or stem injected with 50% Roundup in clean water or basal bark treated with 10% Garlon 600 in diesel oil (Swarbrick, 1997; p. 29-30).

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

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

Taxonomic information about Clausena excavata 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.

Merrill, Elmer D. 1923. An enumeration of Philippine flowering plants, vol. 2 [reprint]. Bureau of Printing, Manila. 530 pp.

Swarbrick, J. T. 1997. Environmental weeds and exotic plants on Christmas Island, Indian Ocean: a report to Parks Australia. 101 pp. plus appendix.

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

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).

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