Biogeographical insights into the spore ecology of Selaginella MARGARONISOFIA 2018 Simple plants can provide novel insights into fundamental ecological processes that might be hidden in more complex plants. I used the world-wide geographic distributions of species of Selaginella, a primitive vascular plant, to show that species-coexistence is affected by competition among spores for regeneration sites, and to test whether colonization of distant islands is more difficult for species with unisexual spores than for species with bisexual spores.