Infraspecific Classification of Aeollanthus myrianthus (Lamiaceae)

Abstract

Summary. The variable tropical African Aeollanthus myrianthus Baker is here divided into two subspecies mainly on the basis of differences in the length of the corolla-tube. Subsp. myrianthus represents the plants with a short corolla tube. The new combination, subsp. gamwelliae (G. Taylor) Ryding, represents the plants with a long corolla tube. The identity of A. myrianthus is discussed, and a neotype of this name is designated. A. medusa Baker is placed in synonymy under subsp. gamwelliae. The variation in A. myrianthus is largely geographically correlated, and Ryding (1986: 84) briefly described about five principal forms of this species. Some of these forms are obviously very indistinct, but Ryding's (1986: Fig. 34) scatter plot suggests that it may be possible to divide the species into three rather well-defined groups on the basis of differences in corolla characters. The first group has a short corolla tube (Ryding 1986: Fig. 33E), and occurs in the northern and eastern part of the distribution area (Sudan, Ethiopia, Congo, Burundi, Uganda, Kenya, Tanzania and Zambia). The second group has a long corolla tube and a long lower lip of the corolla, and occurs in a small area at the southern tip of Lake Tanganyika (Ryding 1986: Fig. 33G). The third group has a long corolla tube and a comparatively short lower lip of the corolla (Ryding 1986: Fig. 33F), and occurs in the south-eastern part of the distribution area (Tanzania, Malawi and Mozambique). The two groups with a long corolla tube are apparently not as distinct as they appear in Ryding's (1986) scatter plot. As mentioned by Ryding (1986), the size of the lower lip of the corolla lip is very variable even within the same plants. If recent collections (such as Bidgood et al. 614 with an intermediate lower lip of the corolla)