The author of the paper provides an overview of the scientific activity and main works of the scientist Petru Tarhon. Born on the same day as Mihai Eminescu, i.e. on the 15th of January 1930, he is one of the few witnesses alive of the Great Romania epoch. During his lifetime, Petru Tarhon manifested himself as a valuable expert in the field of natural sciences. He created two arboreta (in Tiraspol and Chisinau), published didactical editions and monographs, as well as educated dozens of specialists in the field of biology. His autobiographical works contain valuable historical information for a time-span of about ninety years, focusing on university and academic life in the Republic of Moldova.