AFFINITIES, EVOLUTION AND TAXONOMY OF ZYGNEMACEAE (CHLOROPHYCEAE) : A REVALUATION

The family Zygnemaceae (Meneghini, 1838) is characterized by simple or branched filaments, symmetrical cells, elaborate chloroplasts and amoeboid gametes. Transeau (1951), Randhawa (1959) and Kadlubowska (1972) have described 13 genera in their monographs including a questionable genus Entransia Hughes. Later on, Ahmad and Goldstein (1971, 1972) have added another member Lloydiina Ahmad and Goldstein to Zygnemiaceae. Recently, we have described elsewhere two new members Sangirellum and Trigonum (both unpublished) with band shaped or girdle-shaped parietal chloroplast and with rounded triangular to polster form triangular, axile chloroplast respectively. So the family includes altogether 16 genera which are separable from one another by their structure of the chloroplasts. But many notable phycologists (Yamagishi, 1963; Bourrelly, 1966) placed Hallasia Rosen vinge in synonomy with Zygnemopsis and thus Zygnemaceae includes 15 genera only.