en Biology & physiology Biology & physiology پژوهشي Orginal research papers <i><span lang="TR" style="font-size:10.0pt"><span calibri="" style="font-family:"><span style="color:black">Caulerpa racemosa</span></span></span></i><span lang="TR" style="font-size:10.0pt"><span calibri="" style="font-family:"><span style="color:black"> is edible marine green algae of the Caulerpaceae family. <i>C. racemosa</i> is consumed as a sea vegetable in many countries, especially Southeast Asian countries. In recent years, molecular studies caused some changes in the taxonomic positions of the members of the genus <i>Caulerpa</i>. It is necessary to accurately identify species of this genus based on modern molecular studies due to the consumption of some species and also the toxic effect of some other species of this genus. Some species of <i>Caulerpa</i> have already been reported from the southern coasts of Iran based on preliminary morphological studies. The purpose of this study was to collect and accurately identify the species of the genus <i>Caulerpa</i> in the coastal waters of the Persian Gulf and the Gulf of Oman in the southern coastlines of Iran. This study was based on the combination of molecular and morphological characteristics studies of the collected samples of this genus in this area. In the current article, the results obtained about the <i>Caulerpa racemosa</i> are presented. Samples of the genus were collected from different coastal areas of the Persian Gulf and seashores of Oman Gulf along the geographical borders of Iran and transported to the laboratory in cool conditions. After cleaning and washing, some of the cleaned samples were dried in silica gel and used for DNA extraction and thereof PCR process based on <i>tuf</i>A gene. In addition, herbarium samples required for morphological studies were prepared and deposited in the herbarium of Agriculture and Natural Resources Research and Education Center of Hormozgan province. The results of this study relatively solve the confusion in <i>Caulerpa racemosa- peltata</i> complexity for Iranian members of the complex. In addition to morphological features, the current molecular investigation also helped to accurately identification of the members of this complex in the Iranian seashores of the Persian Gulf and Gulf of Oman. As a </span></span></span><span lang="TR" style="font-size:10.0pt"><span calibri="" style="font-family:"><span style="color:black">highlighted conclusion,</span></span></span><span lang="TR" style="font-size:10.0pt"><span calibri="" style="font-family:"><span style="color:black"> the current research on <i>Caulerpa</i> species from the Iranian seashores of the Persian Gulf and Gulf of Oman resulted in resolving two species including<b> </b><i>Caulerpa sertulariodes </i>(S. G. Gmelin) Howe forma <i>farlowii </i>(Weber-Van Bosse) B&oslash;rgesen, which was resolved as</span></span></span><i><span lang="TR" style="font-size:10.0pt"><span calibri="" style="font-family:"><span style="color:black"> Caulerpa selago</span></span></span></i><span lang="TR" style="font-size:10.0pt"><span calibri="" style="font-family:"><span style="color:black"> (Turner) C. Agardh </span></span></span><span lang="TR" style="font-size:10.0pt"><span calibri="" style="font-family:"><span style="color:black">(Salehi Balashahri <i>et al</i>., 2021) and</span></span></span><i><span lang="TR" style="font-size:10.0pt"><span calibri="" style="font-family:"><span style="color:black"> Caulerpa racemosa </span></span></span></i><span lang="TR" style="font-size:10.0pt"><span calibri="" style="font-family:"><span style="color:black">var.<i> macrophysa</i></span></span></span><span lang="TR" style="font-size:10.0pt"><span calibri="" style="font-family:"><span style="color:black"> also resolved as<i> Caulerpa racemosa </i>(Forssk&aring;l) J. Agardh.</span></span></span> Seaweed, Caulerpceae, Gulf of Oman, Persian Gulf, tufA gene, Green algae 713 725 http://jifro.ir/browse.php?a_code=A-10-4658-1&slc_lang=en&sid=1 M. Salehi Balashahri m.salehibalash@gmail.com 100319475328460052588 100319475328460052588 No Islamic Azad University, Science and Research Branch, Tehran, Iran M.M. Dehshiri dehshiri2005@gmail.com 100319475328460052589 100319475328460052589 No Department of Biology, Borujerd Branch, Islamic Azad University, Borujerd, Iran J. Sohrabipour sohrabipour2@gmail.com 100319475328460052590 100319475328460052590 Yes Agriculture and Natural Resources Research and Education center of Hormozgan, Agriculture Research, Education and Extension Organization (AREEO), Iran I. Mehregan iraj@daad-alumni.de 100319475328460052591 100319475328460052591 No Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran