Nigritella dulnigiana is a red Nigritella that occurs sporadically in the Eastern Alps. A larger occurrence can be found on the west side of the Trenchtling in the 'Wildfeld' above Präbichl. Nigritella dulnigiana is a strong Nigritella with an elongated flower head. The form of its labellum is similar to that of Nigritella hygrophila which has dark red ("black") flowers. In the same biotope in the Western part of the Trenchtling also the delicate Nigritella sulzeri with its small, roundish, red flower head is occurring. Both have been described by FOELSCHE in Ber. Arbeitskrs. Heim. Orchid. 40 (2): 101 - 152 (2023, publ. 2024).