Uncovering the habitat and morphological variation of the narrow endemic Centaurea pangaea (Asteraceae): Implications for conservation

• Centaurea pangaea is one of the rarest and little-known endemic plant species of the Genus in Greece. • Significant morphological variation among subpopulations suggests local environmental factors, such as altitude. • The rarity of Centaurea pangaea may be attributed to the absence of dispersal traits, seed predation, and its limited competitive ability. Centaurea pangaea (Asteraceae) is among the Greek endemic species of the genus with a particularly restricted distribution, occurring only on Mt. Pangeon (NE Greece) where it is found in a limited number of microsites. Through extensive field surveys, we confirmed its presence at three microsites, documenting a total of 108 mature individuals. We analyzed morphological traits of individuals sampled in two subpopulations, which revealed significant morphological variability, especially in traits like capitula width and leaf dimensions, likely driven by local environmental differences such as altitude. The absence of a pappus thus remains a stable and reliable diagnostic character distinguishing C. pangaea from C. parilica . Its limited dispersal ability – due to the absence of a pappus and elaiosomes – combined to the heavy predation of its achenes by Larinus weevils and its potentially low competitive ability, seem to play a crucial role in colonizing otherwise suitable habitats. The present study highlights the need for continued monitoring combined with targeted conservation actions to ensure the future survival of this poorly known yet ecologically and taxonomically significant endemic species