Description from Flora of China
Convolvulus biflorus Linnaeus, Sp. Pl. ed. 2., App. 1668. 1763; Aniseia biflora (Linnaeus) Choisy; A. calycina (Roxburgh) Choisy; C. calycinus Roxburgh; C. hardwickii Sprengel; C. plebeius (R. Brown) Sprengel; C. ser Sprengel; C. sinensis Desrousseaux; Ipomoea calycina (Roxburgh) Bentham ex C. B. Clarke; I. cynanchifolia C. B. Clarke, p.p.; I. hardwickii (Sprengel) Hemsley; I. plebeia R. Brown; I. sinensis (Desrousseaux) Choisy; I. timorensis Blume.
Herbs annual, scandent or twining, with ± grayish hirsute axial parts. Stems 1-2 m. Petiole 1.5-8 cm; leaf blade cordate or deltate-cordate, 4-9.5 3-7 cm, hirsute-villous, base cordate, margin entire, rarely slightly 3-lobed, apex acuminate; lateral veins 6 or 7 pairs. Inflorescences 1-3-flowered; peduncle (0-)3-15 mm; outer 3 bracts linear-lanceolate, small. Pedicel 0.8-1.5 cm. Sepals slightly enlarged in fruit; outer 3 deltate-lanceolate, 8-10 4-5 mm, abaxially grayish hirsute-villous, ciliate, adaxially subglabrous, base auriculate; inner 2 linear-lanceolate, ca. as long as or longer than outer 3. Corolla white, narrowly campanulate, 1.2-1.9 cm; limb shallowly lobed, midpetaline bands pubescent. Stamens ca. 3 mm; anthers ovoid-deltoid, base sagittate. Ovary conical, glabrous. Capsule ± globose, ca. 9 mm in diam., glabrous. Seeds ovoid-trigonous, ca. 4 mm, puberulent to tomentellous, margin sometimes white woolly.
The taxonomy of the cordatesepalled, smallflowered ipomoeas in China needs further study. The Fl. Reipubl. Popularis Sin. account differs from other twentieth century floras in recognizing one, Aniseia biflora, instead of two species. The Chinese taxon has pantoporate, spinulose pollen grains, however, which indicates that it is a species of Ipomoea. The five known neotropical species of Aniseia all have nonspinulose, colpate pollen grains. The two issues not resolved in this account are whether one or two species should be recognized in China, and what names are to be applied to them.
Twentieth century floras for Africa, Asia, and Malesia recognize two species of smallflowered Ipomoea with cordate sepals: I. plebeia and I. sinensis. Several authors have pointed out
that the original description of the Linnaean Convolvulus biflorus is ambiguous, and in the absence of any type specimen (at the herbaria LINN or S), they have reduced C. biflorus to
the synonymy of Robert Brown's clearly defined and typified I. plebeia. Chinese specimens called I. (or Aniseia) biflora come very near to what has been called I. plebeia in
contemporary African and Malesian floras.
Ipomoea sinensis, which occurs through much of the Old World tropics, is distinguished primarily by having peduncles to 4.5 cm long. The Fl. Reipubl. Popularis Sin. placed it in
synonymy of Aniseia biflora. For the time being, the epithet biflora, which is well established in the Chinese literature, is here maintained to a single highly variable taxon defined
much as in the Fl. Reipubl. Popularis Sin. A careful study of the entire complex of cordate-sepalled Ipomoea needs to be undertaken, however, to sort out the identities and
nomenclature for the taxa involved.
The whole plant has several medicinal uses.
Valleys, mountain slopes, roadsides, forests, usually in dry places; 200-1800 m. Fujian, Guangdong, Guangxi, Guizhou, Hunan, Jiangxi, Taiwan, Yunnan [India, Indonesia, Japan (Ryukyu Islands), ?Myanmar, Vietnam; E Africa, N Australia]