Lectotypification of two Linnaean specific names in Convolvulaceae

Abstract

1. batatas L., Sp. PI. 154. 1753 [Ipomoea batatas (L.) Lam.]. Lectotype (designated here): Herb. Linn. No.77.5 (S). When Linnaeus published the name batatas in 1753, he cited several synonyms and gave a brief description of the plant in the form of a new phrasename. Although LINN 218.12 has been widely treated as the lectotype, e.g., Verdcourt (1963: 114), Austin (1975: 195; 1980: 320; 1982: 40), Siddiqi (1977: 25), McDonald (1994: 13), Bosser & Heine (2000: 34) & Deroin (2001: 175), this collection lacks the relevant Species Plantarum number (i.e., 7) and is a later addition to the herbarium, received after 1753, and therefore cannot be eligible as the type (Jarvis, pers. comm., 1996). Nicolson & al. (1988) had also pointed out that 218.12 (LINN) was probably a post-1753 addition. However, there are two specimens in the Linnaean Herbarium in London (LINN), numbered 218.11 and 218.13, and another specimen in the Linnaean Herbarium in Stockholm which do bear the relevant Species Plantarum number indicating that they were in Linnaeus' posession in 1753. Consequently these are original material for the name eligible for typification. Unfortunately the specimens in the Linnaean Herbarium in London are sterile, but the specimen in the Linnaean Herbarium in Stockholm has a single leaf and flower. The only other original element associated with the name are three illustrations: a cited Catesby plate (t. 60, Catesby, 1730), which apparently belongs to I. batatas (Howard & Staples, 1983), as does the cited Rheede plate (t. 50; Rheede, 1688) (Nicolson & al., 1988). The third figure from Morison (sec. 1, t. 3, f. 4; Morison, 1680), Convolvulus indicus orientalis inhame s. Batatas is also identifiable as I. batatas. From the six original elements of this name I choose the Stockholm specimen as the lectotype in preference to the cited illustrations and the sterile material in LINN. Although the Stockholm sheet has but one leaf and one flower, the lobed leaf and calyx characters fully agree with current usage of the name.