New Records of Nostocalean Cyanobacteria from Rice Fields in the Golestan Province in North-East of Iran

The algal flora of five stations from paddy-fields of Golestan Province was investigated between October 2006 and September 2007. Eight filamentous heterocystous Nostocacean are recorded here for the first time from paddy fields of iran: Cylindrospermum licheniforme, Cylindrospermum stangnale, Cylindrospermopsis raciborskii, Calothrix ghosei, Gloeotrichia longiarticulata, Aulosira implexa var. crassa, Tolypothrix conglutionata var colorata, Scytonema multiramosum. Cylindrospermum stagnale, Aulosira implexa, Scytonema multiramosum, Tolypothrix conglutionata were dominant species in all stations and seasons, but Gloeotrichia longiarticulata and Cylindrospermopsis raciborskii were observed mainly during the spring and summer. Morphological characteristics of these species are described in detail and information about their ecological distribution is given.