The paper describes the process of expansion of the poetic beginning to the prose of writers whose works represent the key trends of the epoch of the end of the 19th - beginning of the 20th centuries, showing the interest in syncretic phenomena, expressed particularly in the verse and prose interaction. The analysis of the creative work of V. Korolenko, A. Bely, M. Tsvetaeva made it possible to present the peculiarities of Russian prose of the 19th-20th centuries manifested in the combination of poetic and prose elements within the boundaries of one text. A consistent consideration is given to the phenomena arising from the active interaction of prose and verse, such as metered prose, verse, the non-classical visual appearance of prose, the rhythm of prose, and the prosimetry. The analysis of the works of writers with different aesthetic attitudes and key positions revealed a common vector of artistic search associated with the interaction of verse and prose. Vladimir Korolenko's prose featured elements of verse as an ornamental beginning, emphasizing the melodiousness, musicality of the writer's prose, folklore basis of his subjects, proximity to the romantic settings. Andrei Bely's work proved to be a breakthrough, a bright literary experiment, in which the fusion of poetic and prose narrative reached its absoluteness. Marina Tsvetaeva's prose combined essay and lyrical elements, creating new genre samples.