The abandonment of agricultural use of drained fen peatlands contributes to intensified moorshing process and, consequently, faster of wetlands areas degradation. Peat mineralization causes the eutrophication of the habitat which, along with changing humidity, enables the presence of so-called non peat-forming plants. Among the seeds and fruit present in the top layer of degraded marshy soils, there may also be carpological material originating from non peat-forming plants. 12 soil profiles from selected post-marsh meadows in western Poland were the subject of this study. The studies found seeds and fruit of 69 plant species in moorsh layers, 42 of which were peat-forming species but as many as 27 were non peat-forming plants. Of the latter the most common were, among others, Juncus effusus and Juncus conglomeratus, Urtica dioica, which were characterized by the highest quantitativeness of fruit and seeds. Among the recorded non peat-forming species almost 50% belonged to Molinio-Arrhenatheretea class, which means they were species connected with semi-natural and anthropogenic meadows occurring on mineral or organic-mineral soils but also characteristic of muck emerging from degraded fen peatlands. Peat-forming species belonged to Phragmitetea and Scheuchzerio-Caricetea nigrae classes. Studies showed that the set of fruit and seeds of non peat-forming plants found in the upper layers of peat deposit was not dependent on the thickness or type of peat from which the moorsh originated, nor was it dependent on geographical location.