Dunal (1837) originally described the taxon now known as Dunaliella salina (Dunal) Teodoresco, 1905, as consisting of spherical or elliptical cells, red-orange to rust coloured. Teodoresco, in his definition of the species (1905) stated that the zoospores had a green chromatophore but in aged zoospores the entire body, including chromatophore, was red. Thus, by definition, any isolate of Dunaliella which is not capable of turning redorange to rust coloured should not be considered D. salina. Several strains have been reported in the literature under the name D. salina but do not meet the aforementioned criteria. These include UTEX 200 (= Cambridge 19/3), Mil'ko's strain (Mil'ko, 1963 a, b) and Strain No. 6 used by Mironyuk (Drokova, 1970; Drokova, Popova & Tupik, 1964; Drokova & Popova, 1973, 1974; Mironyuk 1969a, b; Mironyuk & Einor, 1968).