The status and typification of Antithamnion cruciatum var. pumilum and its relationship to A. cruciatum var. scandinavicum (Rhodophyta)

Abstract

Lectotype material of Antithamnion cruciatum var. pumilum (= Callithamnion pumilum) is described and its close relationship to A. cruciatum var. cruciatum is confirmed. Variety pumilum is characterized by its small thallus, and the possibility remains that it represents a diminutive ecad of var. cruciatum. However, var. pumilum is clearly distinct from var. scandinavicum, which is here reported for the first time from the British Isles on the basis of material from the south and west coasts of Britain.