Merremia hederacea (Burm. f.) Hallier f., Convolvulaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

English: ivy woodrose

Habit:  vine

Description:  A small creeping or twining vine; "petioles tuberculate; leaves entire or 3-lobed, 1-5 cm long, 1-4 cm wide; outer calyx-lobes 3.5-4 mm long, essentially glabrous, obviously mucronate, obovate-spathulate and notched; inner calyx-lobes to 5 mm long; corolla 1 cm long, yellow; capsule depressed-globose, or subconic, often obscurely 4-angled, finely wrinkled; brown"  (Stone, 1970).

"A twining or prostrate herb; stems slender, glabrous or pubescent, often minutely tuberculate, sometimes rooting at the nodes. Leaf-blade ovate in outline, 1.5-5 cm. long, 1.25-4 cm. wide, obtuse and mucronulate at the apex, cordate at the base, entire, crenate, or shallowly to deeply 3-lobed, glabrous or sparsely hairy; petiole 0.5-6 cm. long, sparsely tuberculate. Flowers solitary or several in lax, branched inflorescences; peduncle 1-10 cm. long, usually glabrous or minutely tuberculate; pedicels 2-4 mm. long, similar. Sepals obovate to spathulate, outer 3.5-4 mm. long, inner up to 5 mm. long, notched at the mucronulate apex, glabrous or sparsely pilose. Corolla yellow or white, campanulate, 6-12 mm. long, glabrous outside, pilose inside at the base. Capsule globose or conic, somewhat 4-angled, 5-6 mm. long; valves reticulately wrinkled. Seeds pubescent or glabrous, 2.5 mm. long"  (Aluka).

Habitat/ecology:  In Guam, "weedy in wet localities in disturbed areas"  (Stone, 1970).  In China, "Scrub, grassy roadsides in tropical areas; 100-800 m"  (Flora of China).

Propagation:  Seed

Native range:  Africa, tropical Asia, Australia (GRIN).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Federated States of Micronesia Yap Islands	Yap (Waqab) Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 227)
Guam Guam Island	Guam Island	probably introduced invasive	Stone, Benjamin C. (1970) (pp. 495-496)
Guam Guam Island	Guam Island	introduced	Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 227)
Japan (offshore islands) Bonin (Ogasawara) Islands	Bonin (Ogasawara) Islands		Harvard University (2007)
New Guinea (Indonesia and Papua New Guinea) New Guinea Island	New Guinea Island		Harvard University (2007)
Palau Palau (main island group)	Koror Island	introduced invasive	Space, James C./Lorence, David H./LaRosa, Anne Marie (2009) (p. 6) Down the road from the Yuhi Hotel, climbing over trees and other vegetation. Voucher cited: Lorence 9708 (BNM, PTBG)
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)	native	U.S. Dept. Agr., Agr. Res. Serv. (2009)
Philippines Philippine Islands	Philippine Islands	native	U.S. Dept. Agr., Agr. Res. Serv. (2009)

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)	Northern Territory	native	U.S. Dept. Agr., Agr. Res. Serv. (2009)
Australia Australia (continental)	Queensland	native	U.S. Dept. Agr., Agr. Res. Serv. (2009)
Cambodia Cambodia	Cambodia (Kingdom of)		Harvard University (2007)
China China	China (People's Republic of)		Harvard University (2007)
Indonesia Indonesia	Indonesia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2009)
Japan Ryukyu Islands	Ryukyu Islands		Harvard University (2007)
Malaysia Malaysia	Malaysia (country of)		Harvard University (2007)
Thailand Thailand	Thailand (Kingdom of)		Harvard University (2007)
Vietnam Vietnam	Vietnam (Socialist Republic of)		Harvard University (2007)

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

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

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

References:

Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce. 1979. A geographical checklist of the Micronesian dicotyledonae. Micronesica 15:1-295.

Harvard University. 2007. Flora of China (online resource).

Space, James C./Lorence, David H./LaRosa, Anne Marie. 2009. Report to the Republic of Palau: 2008 update on Invasive Plant Species. USDA Forest Service, Hilo, Hawai‘i. (In press).

Stone, Benjamin C. 1970. The flora of Guam. Micronesica 6:1-659.

U. S. Government. 2009. Integrated Taxonomic Information System (ITIS) (on-line resource).

U.S. Dept. Agr., Agr. Res. Serv. 2009. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.