“…Limited data have been obtained from the physical or genetic maps of the unicellular strains Synechococcus PCC 6301 (Tomioka et al, 1981), Synechococcus PCC 7002 (Chen & Widger, 1993) and Synechocystis PCC 6803 (Kaneko et al, 1996). Further information is available from the sequences of the 16S rRNA-23S rRNA ITS domain in members of several cyanobacterial genera that include the unicellular Synechococcus PCC 6301 (Tomioka & Sugiura, 1984), Synechocystis PCC 6803 (Kaneko et al, 1996) and 47 strains of the genus Microcystis (Otsuka et al, 1999), the filamentous (non-heterocystous) Arthrospira PCC 7345 (Nelissen et al, 1994), Spirulina PCC 6313 (Nelissen et al, 1994) and Trichodesmium NIBB 1067 , the heterocystous Nodularia BCNOD 9427 (Hayes & Barker, 1997) and a strain of uncertain generic identity, ' Mastigocladus HTF ' strain PCC 7518 (G. Van der Auwera & A. Wilmotte, personal communication). In addition, the sequence of the ITS of the photosynthetic cyanelle of Cyanophora paradoxa has been determined (Janssen et al, 1987).…”