Merremia yunnanensis

Nomenclature

Accepted name/Authority/Place of publication:

Merremia yunnanensis (Courchet & Gagnep.) R. C. Fang, Fl. Reipubl. Popularis Sin. 64(1): 74. 1979.

Description

Habit:

Herbs perennial, with fusiform tubers; axial parts densely pubescent. Stems twining, striate.

Leaves:

Petiole 4–20 mm; leaf blade rhombic, rhombic-ovate, or nearly circular, 3–10.5 × 1.5–10 cm, densely dull yellow sericeous, glabrescent, base cuneate, margin entire, apex abruptly acuminate or acute, rarely obtuse and mucronulate.

Inflorescences:

Inflorescences 1–3- to many flowered; peduncle 2–12.5 cm; bracts scale-like, 2–3 mm, pubescent. Pedicel 7–10 mm, thicker than peduncle, glabrous.

Flowers:

Sepals unequal; outer 2 sepals obovate-oblong, 8–12 mm, abaxial surface pubescent, mucronulate; inner sepals obovate or elliptic, 1.3–1.4 cm, apex obtuse. Corolla lilac or pink to white, narrowly campanulate, 3.5–4 cm; limb shortly 5-lobed; lobes dull yellow ciliate, mucronulate. Stamens unequal; filaments dilated basally, pubescent. Ovary glabrous.

Fruits:

Capsule oblong, 7–9 mm.

Seeds:

Seeds black, ca. 5 mm, glabrous.

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 (Sichuan, Yunnan). Endemic.

Ecology:

Grassy,
shrubby mountain slopes, pine forests, thickets, forests; 1400–3000 m.

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.

Other information

Common names and uses:

lan hua tu gua (Chinese).

General comments:

Fang & Huang (Fl. Reipubl. Popularis Sin. 64(1): 74. 1979) describe Merremia yunnanensis with corollas pale blue. In this account, the corolla is described as lilac, pink, or white. Specimens at A and K, apparently this species, have labels indicating corolla colors pale yellow, pale yellow tinged rose, canary yellow, and even blue (teste Wilson 4183 at K). Yellow or white corollas are common in Merremia; lilac, pink, and rose are unusual, and blue is unheard of. So broad an array of corolla colors in a single species is anomalous in the genus, and warrants further investigation. Ideally, an array of specimens from Chinese herbaria should be compared with type specimens and historical material at A, E, K, and elsewhere. Until such careful comparison can be made, we maintain Fang & Huang's concept for M. yunnanensis, albeit dubiously. It is possible that some early collections have incorrect label data with respect to color color and this has been repeated faithfully (if inaccurately) in contemporary floras.

Infraspecific Characters:

Chinese floras recognize 3 varieties, which can be separated by the following key:

1a. Corolla pink to white; leaves rhombic or rhombic-ovate var. pallescens

1b. Corolla lilac; leaves broadly rhombic to nearly circular.

2a. Leaf blade densely dull yellowish sericeous var. yunnanensis

2b. Leaf blade nearly glabrous or sparsely sericeous var. glabrescens