Solitary plants do as well as clumped ones in Silene uniflora (Caryophyllaceae)

Many studies have been done on seed production as a function of population density in wild plants. Most of them show a higher seed-set per flower of densely growing plants. In this study, in a gynodioecious Silene uniflora (Caryophyllaceae) population on the Baltic island of Öland, high plant density did not increase fruit-set or seed-set. Instead, the total number of seeds set was slightly higher for widely scattered plants as a result of a somewhat lower number of ovules per flower in densely growing plants. Individuals had nothing to gain by growing close together, because there was no reproductive parameter which could compensate for the low ovule number per flower of closely growing plants. Plant size determined the total seed production of individuals, but did not correlate with any of the fitness components studied per flower basis. The different gender morphs showed the same pattern, which is discussed as a comparison with pollen limitation in self-compatible and self-incompatible plants.