SZELĄG Z. <em>Hieracium umbellonigritum</em> (Asteraceae), a new hybridogenous species from the Sudetes in Poland. Phytotaxa [Internet]. 2023 Mar. 28 [cited 2025 Mar. 25];589(3):289-92. Available from: https://phytotaxa.mapress.com/pt/article/view/phytotaxa.589.3.8