A physical map of the E. gracilis chloroplast genome was constructed, based on cleavage sites of E. gracilis chloroplast DNA treated with bacterial restriction endonucleases. Covalently closed, circular chloroplast DNA is cleaved by restriction endonuclease SalI [Streptomyces albus] into 3 fragments and by restriction endonuclease BamHI [Bacillus amylolique faciens] into 6 fragments. These 9 cleavage sites were ordered by fragment MW analysis, double digestions, partial digestions and digestion studies of isolated DNA fragments. A fragment pattern of the products of EcoRI [Escherichia coli] restriction endonuclease digestion of Euglena chloroplast DNA is described. One of these fragments was located on the cleavage site map.