Investigation on the genus Epilobium in Lithuania during two periods is analysed. The first period starts from the beginning of botanical investigations in Lithuania till 1971; the second – from 1972 to 2009. The 4th volume of the monograph “Lietuvos TSR flora” [Flora of the Lithuanian SSR] published in 1971 completes the first period. The summarized data on the Epilobium genus is presented in the mentioned publication (Natkevičaitė-Ivanauskienė, 1971). The duration of the period and amount of the collected data are not proportional. The special investigations of the genus are efficient: the quantity and quality of information collected during several years of special research of the Epilobium genus exceeds the data of several decades of general flora and vegetation investigations. Separate species of the Epilobium genus are not equally examined recently. Detailed data in various aspects based on abundant material are published only about E. ciliatum. The amount of data about E. tetragonum is rather considerable but is not summarized yet. In spite of abundant total amount of the data on the Epilobium genus, the information about several species is still insufficient. There is some uncertainty about the occurrence of E. obscurum and survival of E. collinum in Lithuania. The monograph “Lietuvos TSR flora” is still a genuine and the only information source about the major part of the species from the Epilobium genus (E. hirsutum, E. montanum, E. palustre, E. parviflorum, E. roseum) in Lithuania. But despite this fact, the last 40 years period after publishing the mentioned monograph distinguishes by the appearance of new research directions.
Keywords: Lithuania, flora, investigations, Epilobium, distribution, habitats, communities.