The manual provides information about the features of seaweed and lichens, which should be studied during the summer practice of students. The ecology and significance of these organisms in nature and for humans, the methodology for conducting excursions, studying objects in the laboratory, the difficulties that may arise in their determination are considered. Keys are given to determine the main genera of the studied objects, as well as a key to determine the species of lichens in the absence of sexual reproduction organs. Dictionaries of algological and lichenological terms and a brief dictionary of general terms are presented. For students and university professors.