Although the factors shaping plant species richness patterns across the islands of the central Aegean are well known, the processes driving the assembly of these island communities remain unclear. To shed light on these processes, we identified biogeographical modules within the phytogeographical area of the Cyclades and tested for nestedness across the islands.The Cyclades, Greece.We used a network approach to detect island biogeographical roles and modules, based on a large and detailed database of the Greek endemic plant taxa of the Cyclades, and we tested for nestedness in the island–species matrices.The Cyclades were significantly modular and divided into five biogeographical modules. Three of the modules were significantly nested and two displayed all four possible biogeographical roles (connectors, module hubs, network hubs, peripherals). Most of the …