Merremia gemella

Nomenclature

Accepted name/Authority/Place of publication:

Merremia gemella (Burm. f.) Hallier f., Bot. Jahrb. Syst. 16: 552. 1893.

Synonyms:

Convolvulus gemellus Burm. f., Fl. Indica 46, t. 21. 1768

Ipomoea gemella (Burm. f.) Roth, Nov. Pl. Sp. 110. 1821.

Ipomoea polyantha Miq., Fl. Ned. Ind. 2: 613. 1857.

Ipomoea radicans Blume, Bijdr. (1825) 712, nom. illeg.

Ipomaea cymosa Roem. & Schultesvar. radicans Miquel,Fl. Ind. Bat. 2 (1857) 613.

Description

Habit:

Herbs, twining or prostrate; axial parts smooth, appressed yellowish pubescent. Stems often rooting at nodes and internodes.

Leaves:

Petiole 1.5–6 cm, rarely minutely tuberculate; leaf blade often ovate, 2.5–6.5 × 1.5–4.3 cm, glabrous or short pilose, base broadly cordate, proximal margin entire, undulate or coarsely crenate, sometimes 3-lobed, apex ± attenuate, mucronulate.

Inflorescences:

Inflorescences umbelliform or forked with short raceme-like branches, few flowered; peduncle 2.5–10 cm; bracts early deciduous, minute. Pedicel 3–6 mm.

Flowers:

Sepals broadly obovate to ± circular, ± unequal, margin scarious, emarginate, slightly mucronulate or not, slightly enlarged in fruit; outer 2 sepals 4–6 mm, abaxial surface ± pilose; inner 3 sepals 6–7 mm, subglabrous. Corolla yellow, campanulate to funnelform, 1.5–2 cm, midpetaline bands dark, glabrous outside; limb shallowly 5-lobed; lobes emarginate and mucronulate. Filaments pubescent basally. Ovary glabrous.

Fruits:

Capsule depressed-globose, ca. 7 mm, coarsely wrinkled.

Seeds:

Seeds trigonous, dark gray or brownish puberulent.

Author:

Fang R.C. & G. Staples

References:

Fang R.C., G. Staples, et al. 1995. Convolvulaceae in P. Raven & C.Y. Wu (eds.) Flora of China 16: 271–325.

Cytology

Chromosome number:

Author:

Fang R.C. & G. Staples

References:

Fang R.C., G. Staples, et al. 1995. Convolvulaceae in P. Raven & C.Y. Wu (eds.) Flora of China 16: 271–325.

Biogeography, Ecology and Natural History

Distribution Map:

Distribution:

China (Taiwan),?Cambodia, Indonesia, ?Laos, Malaysia, ?Myanmar, New Guinea, Philippines, Sri Lanka, Thailand, Vietnam; Australia(Western Australia, Northern Territory, Queensland)

Ecology:

China: Thickets,
roadsides, waste places; 0–200 m.

Thailand: Roadsides
and disturbed areas, open clearing in primary evergreen forest on limestone;
altitude: 0–375 m.

Phenology:

Flowering: January, November, December; fruiting: December.

Author:

Fang R.C. & G. Staples

References:

Fang R.C., G. Staples, et al. 1995. Convolvulaceae in P. Raven & C.Y. Wu (eds.) Flora of China 16: 271–325.

Staples, G. 2010. Convolvulaceae. Fl. Thailand 10(3): 330–468.

Johnson, R. W. Austrobaileya 8: 55–63. 2009

Other information

Common names and uses:

jin hua yu huang cao (Chinese). Thai sa uek yai (Thai). Lawattan, tatapajan (Sundanese). Lawatan, rawatan, lawatan kuning, sampar kidang, indjen indjèn (Javanese). Keritang tikus (Kutai), beloka, djonge djonge, walein- sengit, amut peror (Celebes), Philippines: bangbañgau, marakamóte (Ilokano), kamokamotίhan (Pangasinan), talanuk (Tagalog).

Infraspecific Characters:

KEY TO THE VARIETIES

1. Corolla 1½ - 2 cm long var. gemella

1. Corolla 3-3½ cm long var. splendens