Carex nigra with its very large distribution area is very variable and generates local forms. According to the Flora Europaea this goes up to, for example, dwarf Carex bigelowii-like forms in some peripheral areas of the species. The depicted, somewhat untypical Carex nigra grows in large numbers on the edge of a pond between Sölk-Pass and Hornfeldspitze in the Wölzer Tauern (Central Austria) on crystalline substrate. Their spikes are significantly slimmer than those of typical Carex nigra.