Fern family (Thelypteridaceae)
Longlived fern with long, creeping rhizomes, from which there arise, singly, straight-standing delicate leaves of length 30-80 cm. Leaf-stalk as long as blade, latter being lanceolate in shape, compound, with pinnatifid leaflets. 2nd-order sections elongate, with blunt ends and entire margins. Sori are round, producing spores in Jul.-Sep. Grows on moist to wet, fertile or moderately fertile soils. Occurs in alder-currant forest, or the form with bog-mosses, while dominant in marshy birch forest, if rarely met with in ash-alder riparian forest. Also present on wet peaty meadows and in fens.
Descriptions devised by the team at the Independent Department of Forest Botany, Warsaw University of Life Sciences, i.e. L. Witkowska-Żuk, K. Marciszewska, W. Ciurzycki, A. Obidziński and P. Zaniewski.