Genetic and morphological data fail to differentiate Chara intermedia from C. baltica, or C. polyacantha and C. rudis from C. hispida

Abstract

Genetic variation of five species belonging to the section Hartmania - Chara baltica, C. intermedia, C. hispida, C. polyacantha and C. rudis - was investigated using Amplified Fragment Length Polymorphism (AFLP) techniques. Chara intermedia can be distinguished from the others by the presence or absence of numerous morphological characters. However, probably because of the high variability of the morphological features and common occurrence of apparently transitional forms, more than 80 specimens of the five species were collected and analysed. The specimens were collected from a total of 24 sites, including freshwater localities and sites in the Baltic Sea, initially classified into the five species based on morphological features, and then analysed using AFLP; as an outgroup we used C. globularis. The specimens formed two groups, the first group comprising C. intermedia and C. baltica, the second C. hispida, C. rudis and C. polyacantha. No consistent genetic differences were found between species within each of the two groups. Transitional forms of C. hispida/C. rudis were placed in a clade between individuals of C. hispida and C. rudis. Local populations of some charophytes differ morphologically from one another, possibly as a result of local adaptation. © 2013 Copyright British Phycological Society.