The typification of achnanthes bory based on echinella stipitata lyngbye, with an account of the morphology and fine structure of lyngbye's species

Achnanthes was described by Bory to include three species, A. adnata, A. dubia and A. baccillarioides, formerly included under Echinella stipitata Lyngbye. Boyer typified the genus Achnanthes using A. adnata and this typification has been accepted by subsequent authors. However no extant material of A. adnata is known. Since this species was based on E. stipitata, Lyngbye material was sought and examined. This material contains specimens of Achnanthes sensu stricto and can be used as the generitype of that genus. Light and electron microscopical observations of this material are presented. C. A. Agardh created the name Achnanthes brevipes as an avowed substitution for A. adnata and this is the name that has generally been used. There is little doubt that E. stipitata, A. adnata and A. brevipes refer to the same species. Since A. brevipes has been used most extensively in the literature there is a case for conserving this name. Based on our observations we propose that Lyngbye's material be accepted as the type for Achnanthes but that the name A. brevipes be considered for conservation against E. stipitata and A. adnata.