Ipomoea biflora

Twentieth century floras for Africa, Asia, and Malesia recognize two species of small-flowered Ipomoea with cordate sepals: I. plebeia R. Br. and I. sinensis (Desr.) Choisy. Several authors have pointed out already that the original description for Convolvulus biflorus L. is ambiguous, and in the absence of any type specimen at the herbaria LINN or S, they have tentatively referred Linnaeus’ name and later combinations based upon it to the synonymy of Robert Brown's clearly defined and typified I. plebeia, which has solitary flowers or 2–5-flowered inflorescences that are sessile or with a peduncle at most 3 mm long. Chinese specimens called I. biflora come very near to what has been called I. plebeia in contemporary African and Malesian floras.

            Authors of these same floras recognized a second species that ranges through much of the Old World tropics, I. sinensis, distinguished primarily by inflorescences having a peduncle to 4.5 cm long. For the time being, we have provisionally applied the name I. biflora to a single taxon, because it is possible, even likely, that a single highly variable species ranges throughout the Old World tropics. The selection of a neotype specimen for Ipomoea biflora (Staples & Jarvis, Taxon 55: 1020. 2006) stabilized the application of this name. 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, and to verify that this is indeed a suitable disposition.