Reproductive biology of Santolina ligustica Arrigoni

Understanding the breeding system, the reproductive success and long‐term demographic patterns of endemic species is fundamental to improve strategies for their conservation. Santolina ligustica Arrigoni (Asteraceae) is an endemic perennial shrub limited to a few localities in Eastern Liguria (NW Italy), and it grows on ophiolitic substratum. The species is considered “Near Threatened” (NT)according to Red List of the Italian Flora. In this study, we investigated the reproductive biology of S.ligustica and assessed its reproductive success. More specifically, we: (a) evaluated the type and the frequency of pollinators; (b) quantified the effort and reproductive success of the plants by tests on capitula (open‐pollinated and bagged) and (c) evaluated the seeds’ germination performance. A total of 46 different taxa of insects were observed. The most abundant visitors were mainly Coleoptera (77%) and Hymenoptera (19%), suggesting a generalist pollination system. In the open‐pollinated capitula, the 7.87 % (SD 11.93) of the florets produced well‐formed cypselae, while the bagged capitula did not produce fruits. These results suggest that the plant is auto incompatible and the pollinators activity is crucial. Despite the high visitation rate observed, S. ligustica showed a low fruit‐set per each capitulum. Seeds of S.ligustica can germinate over a wide range of conditions immediately after harvesting, suggesting that seeds are nondormant. Maximum germination occurs between 15 °C and 22 °C, temperatures that are in line with germination occur in early autumn, after the summer in Mediterranean environment characterized by dry conditions.