STUDIES ON THE GENUS ASTERELLA (AYTONIACEAE) VI: INFRAGENERIC CLASSIFICATION IN ASTERELLA

Abstract

  A review and assessment are presented of the three existing classifications of species within the genus Asterella. Based on recent morphological and molecular studies additional characters such as spore colour and ornamentation are considered important in classification. A new subgeneric classification is presented, which groups the 48 provisionally accepted species into five subgenera, Asterella, Saccatae, Wallichianae, Phragmoblepharis and Graciles. Subgenus Asterella is divided into two sections, Asterella and Brachyblepharis, subg. Wallichianae into two sections, Wallichianae and Californicae, the latter described as a new section containing only A. californica. Subg. Phragmoblepharis cannot be satisfactorily divided into sections at present. A key is provided to the subgenera and sections along with descriptions and a list of accepted species in each.