Composition and structure of epiphytic algae on two aquatic macrophyta speciese distribution on the Euphrates (Al-Abassia) River, Iraq

The present work included study of epiphytic algae on two species of aquatic plants (Potomogeton crispus and Eusine indica) of the Al – Abasia / Euphrates river in middle region of Iraq from March 2012 to February 2013. The investigation region encompassed four Location along 28 Km of the river course the study was recorded 152 species of epiphytic algae on both host plants species and comprised of Bacillariophyta (70%), chlorophyta (22%) and cyanophyta (8%) Total number of epiphytic algae was ranged between 117.03 x103was individual / g as low value on shoot of E. indica and 12801.12 x103individuals /gm as high value on leave of P.crispus. Some species were recorded as dominance during most of the study period on both host plant species, such as Osillatoria sp.; Scendesmus sp.; Cyclotella comta; Nitzshia sp.; Melosera italic and Navicula easpidata. The results showed high species richness and low diversity of epiphytic algae according to Shannon index in all study sites.