Massoumeh Farasat - Marine Pharmaceutical Science Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
Seyed mohammad Bagher Nabavi - Department of Marine Biology, Khorramshahr University of Science and Technology, Khorramshahr ,Iran
Ramazan Ali Khavari-Nejad - Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
Foroogh Namjoyan - Marine Pharmaceutical Science Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran

In many countries, algae have a high economic significance and are used in food, medicine and cosmetic industries. The sea lettuces comprise the genus Ulva, a group of edible green algae that is widely distributed along the coasts of the world's oceans. Due to the fundamental similarities between different species of this genus, it is very difficult to identify different species from each other. In this study, the morphological and anatomical characteristics of ۶ species (U. clathrata, U. intestinalis, U. prolifera, U. flexuosa, U. linza and U. compressa) collected from nine coastal areas of Bushehr province are investigated. Morphological and anatomical examinations were done with the aid of stereomicroscope and light microscope. Characteristics that examined and compared were: the color and shape of the thalli, width and height of the thallus, form of the branches, cell shape, length and width of the cells, arrangement of the cells in the thalli, shape and position of chloroplasts and the number of pyrenoids in each chloroplast. Then, the results were compared with the those of the previous researchers' descriptions

Persian Gulf”, “Green seaweeds”, “Ulva spp”.