The composition and distribution of freshwater Cyanobacteria and algae in Makkah area of Saudi Arabia were investigated. The total number of recorded species was 107, 37 Cyanobacteria, 34 Bacillariophyta, 29 Chlorophyta, 6 Euglenophyta and one species Pyrrohophycophyta.
The most common genera were Oscillatoria (14 spp.), Spirogyra (8 spp.), Navicula (7 spp.), Nitzschia (7 spp.), Gloeocapsa and Euglena (each with 4 spp.). On the other hand, the most widely distributed species in the investigated area were Merismopedia elegans, Oscillatoria Amphibia and O. Tenuis.
Al-Taif locality was characterized by having large number of Cyanobacterial and Algael species (64 spp.).
Among the dominant algae in Makkah area, the greeen alga Oedogonium gracilis was chemically investigated. The pharmacopoeial constants, phytochemically screening and total amino acids were detected. O. gracilis was characterized by having high amount of ash and protein. 17 amino acids were identified and determined. The prefominant amino acids were glutamic acid, alanine, aspartic acid and leucine.