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]

Chinese: li lan wang

English: ivy woodrose

Yapese: watchagar

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)
French Polynesia Society Islands	Tahiti Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2011) Voucher cited: J. Florence 7717 (PAP) Adventice
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		Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2011)
New Guinea (Indonesia and Papua New Guinea) New Guinea Island	New Guinea Island		Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2011)
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 (PTBG, BNM, NY, US)
Palau Palau (main island group)	Koror Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (2008) (voucher ID: PTBG 1) Taxon name on voucher: Merremia hederacea (Burm. s.) Hallier f.
Papua New Guinea Bismarck Archipelago	Bismarck Archipelago		Peekel, P. G. [translated by E. E. Henty] (1984) (p. 469) Not abundant; in lawns, hedges and Imperata grassland.
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. (2011)
Philippines Philippine Islands	Philippine Islands	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Philippines Philippine Islands	Philippine Islands	native	Merrill, Elmer D. (1923) (p. 361) In thickets and in open grasslands 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
Australia Australia (continental)	Northern Territory	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Australia Australia (continental)	Queensland	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Cambodia Cambodia	Cambodia (Kingdom of)		Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2011)
China China	China (People's Republic of)		Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2011)
China China	Hong Kong	native	Wu, Te-lin (2001) (p. 224) In thickets or in grasses along roadside.
Indonesia Indonesia	Indonesia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Japan Japan	Japan (country)	introduced	Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 187)
Japan Ryukyu Islands	Ryukyu Islands		Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2011)
Malaysia Malaysia	Malaysia (country of)		Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2011)
Singapore Singapore	Singapore (Republic of)	native	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 60) Common
Thailand Thailand	Thailand (Kingdom of)		Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2011)
Vietnam Vietnam	Vietnam (Socialist Republic of)		Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2011)

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:

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.

Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. 2011. Base de données botaniques Nadeaud de l'Herbier de la Polynésie Française (PAP). (online resource).

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

Merlin, M./Kigfas, A./Keene, T./Juvik, J. 1996. Giddi nge gakiiy nu Wa‘ab: Plants, People and Ecology in Yap State. Program on Environment, East-West Center, Honolulu, Hawai‘i, 121 pp.

Merrill, Elmer D. 1923. An enumeration of Philippine flowering plants, vol. 3 [reprint]. Bureau of Printing, Manila. 628 pp.

Mito, Toshikazu/Uesugi, Tetsuro. 2004. Invasive alien species in Japan: the status quo and the new regulation for prevention of their adverse effects. Global Environmental Research 8(2)/2004: 171-191.

National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.). 2008. Voucher specimen #PTBG1(David H. Lorence 9708).

Peekel, P. G. [translated by E. E. Henty]. 1984. Flora of the Bismarck Archipelago for naturalists. Office of Forests, Division of Botany, Lae, Papua New Guinea. 638 pp. ISBN 9980-66-000-7.

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. 227 pp.

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

U. S. Government. 2011. Integrated Taxonomic Information System (ITIS) (on-line resource).

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

Wu, Te-lin. 2001. Check List of Hong Kong Plants. Hong Kong Herbarium and the South China Institute of Botany. Agriculture, Fisheries and Conservation Department Bulletin 1 (revised). 384 pp.

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