Flowering phenology and female reproductive success in Silene acutifolia Link ex Rohrb

We investigated flowering phenology and female reproductive success in two populations of Silene acutifolia in northwest Spain, over one year (population A) or two consecutive years (population B). Flowering phenology was similar in the two populations and two years. However, significant interannual and interindividual variation was detected in flowering start date, flowering finish date, flowering duration, relative flowering intensity, flowering synchrony index, and median flowering date (the date on which half a plant's flowers had opened). The between-year differences may be partly attributable to the fact that the first year was markedly warmer than the second year. The order in which individual plants started flowering was highly consistent between years, which may reflect genetic control and/or microhabitat heterogeneity. Multiple regressions with fruit set or seed set as the response variables indicated that none of the phenology descriptors, or number of flowers, were significant predictors of female reproductive success.