Relative sexuality in Ectocarpus siliculosus

181 plants of the marine brown alga Ectocarpus siliculosus were collected at Naples, Italy, and clonal cultures established. 94 female and 82 male gametophytes were identified. 5 plants were asexual, although they had the characteristic morphological appearance of gametophytes. There is very clear and stable sexual bipolarity and no indication of relative sexuality as described by Hartmann. Examination of Hartmann's publications and observations on the cultured material showed several possible ways how his misinterpretations may have originated.