The Sitsa flora was first described by M. D. Zalessky in 1929. He investigated the collection sampled by M. A. Pavlov, I. A. Klock, and A. V. Martynov from the Malaya Sitsa River basin in the Partizansk region. Of the forms he described, only Pecopteris anthriscifolia Goeppert had been known earlier. The other species (Pecopteris maritime Zalessky, Callipteris sahnii Zalessky, C. orientalis Zalessky, C. congermana Zalessky, Thinnfeldia pavlovi Zalessky, Odontopteris ussuriensis Zalessky, Scapanophyllum sitzense Zalessky, Ctenis renaulti Zalessky) were described as being new species. There were also some species (Annularia schurowskii Schmalhausen, Phyllotheca cf. deliquescens Eichwald, and Noeggerathiopsis aegualis Goeppert) that were reported only in text. Those data suggested a late Permian age for the Sitsa flora. At the same time, Zalessky found some forms in his collection “that foretold the beginning of Mesozoic time” (Zalessky, 1929a, p. 124).
Later, Zalessky (1929b, 1930) described four other species (Synopteris demetriana Zalessky, Sitzia kloki Zalessky, Sitzopteris superba Zalessky, and Rhipidopsis elegans Zalessky). He concluded that the presence of Pecopteris anthriscifolia Goeppert in the Sitsa flora made it comparable with the late Permian floras of Pechora (Pechora Formation) and Kuznetsk (Kolchuginskian Formation).
When late Permian plant fossils were found in other localities of South Primorye, the question arose as to the position of the Sitsa Suite in the Upper Permian section of the region (the type of the suite is located in the type region of the Sitsa flora).