The synecology of endemic relict species <i>Ramonda serbica</i> (Gesneriaceae)

The article presents the results of a study of the plant communities of <i>Ramonda serbica</i>, primarily intended to increase knowledge of their species and syntaxonomic diversity. The dataset included 204 vegetation plots (relevés) of the two Balkan Ramondas (<i>R. serbica</i> and <i>R. nathaliae</i>), 174 digitised from published literature sources and 30 new ones from field sampling of <i>R. serbica</i> in Montenegro and North Macedonia. Nineteen associations and subassociations of <i>R. serbica</i> were identified, using hierarchical cluster analysis (the Sørensen index as a distance measure and the Flexible Beta method, ß −0.25). Three associations (<i>Micromerio julianae-Ramondetum serbicae</i>, <i>Hylocomio splendentis-Ramondetum serbicae</i>, <i>Neckero pumillae-Ramondetum serbicae</i>), three subassociations (<i>Micromerio julianae-Ramondetum serbicae</i> subass. <i>allosoretosum persicae</i>, <i>Ceterachi officinarum-Ramondetum serbicae</i> subass. <i>festucetosum dalmaticae</i> and subass. <i>hylotelephietosum maximi</i>) and one alliance <i>Exsertotheco crispae-Ramondion serbicae</i> are described as new. Both hierarchical cluster analysis and non-metric multidimensional scaling ordination support the distinction of 3 chorological/ecological groups of <i>R. serbica</i> communities: Adriatic-Ionian (xerophilous), Moesian (xero and mesophilous communities) and Illyrian-Scardo-Pindic (hygromesophilous). Communities of the Adriatic-Ionian cluster belongs to alliances <i>Edraianthion</i>, <i>Centaureo cuspidatae-Portenschagillion ramosissimae</i> and <i>Campanulion versicoloris</i>, of the Moesian one to <i>Edraiantho graminifolii-Erysimion comati</i>, and the Illyrian-Scardo-Pindic one to novel alliance <i>Exsertotheco crispae-Ramondion serbicae</i>.