Nomenclatural changes in Spilanthes and Blainvillea with remarks and a key to the species of Spilanthes in the Malay Archipelago

There has been considerable confusion over the name Verbesina pseudoacmella and V. acmella published by Linnaeus in the Species Plantarum (1753, p. 901). He applied these names to definitions taken from his earlier work, Flora Zeylanica (1748, p. 144, 145, nos. 308 and 309), with only one unimportant alteration. The title page of the Flora Zeylanica shows that the book is intended as an account of Hermann’s plants, and this is confirmed for the two species concerned by the close agreement between the descriptions published and the specimens in Hermann’s Herbarium preserved in the Department of Botany of the British Museum. These two Linnean species must, therefore, be interpreted by reference to Hermann’s specimens, regardless of the fact that figures cited by Linnaeus in the synonymy of each species (viz. Seba, Thesaur. 1, t. 10, 11; Plukenet, Alm. t. 159, f. 4) are of the plant which generally has been known as Spilanthes acmella. In 1888, Trimen published notes on Hermann’s Herbarium (Journ. Linn. Soc. Lond. (Bot.) vol. 24, p. 129); he identified the specimens representing these two species as follows: No. 308, Verbesina pseudo-acmella, as possibly a young specimen of Wedelia biflora DC.; and No. 309, Verbesina acmella, as Blainvillea latifolia DC. A drawing included in the herbarium he identified as “Spilanthes acmella”. As this drawing was not mentioned by Linnaeus, it must not be considered when interpreting the species. In his revision of the genus Spilanthes, A. H. Moore (Proc. Amer. Acad. Arts & Sci. 42, 1907, p. 521) rejected the name Verbesina pseudoacmella L. as referring to a mixture of genera, but retained “Verbesina acmella L.” as the basis of a species of Spilanthes.