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This study documents the comparative success of seeds and seedlings of the perennial gynodioecious-gynomonoecious weed, Silene vulgaris. in the greenhouse. The importance of experimental design is stressed by comparing two different statistical analyses ofthe data. Seeds were obtained from artificial pollinations in the field: self-fertilization of hermaphrodites, and crossfertilizations of both hermaphrodites and females. One-way analysis of variance using progeny type (selfed hermaphrodites, outcrossed hermaphrodites, and outcrossed females) as the treatment effect for each seed and seedling variable showed statistically discernable differences among progeny from different cross types. The significance of this type of ANOV A resulted from a reduced error term and positively-biased F ratios. A factorial design showed no significant differences due to type of progeny in seed mass, days to germination, leaf number, area, or biomass at six weeks of age. There were, however, significant differences among seeds attributable to maternal parent for all seed and seedling variables. A higher proportion of seeds from outcrossed individuals germinated compared to that from self-fertilization. When the data were analyzed to include and partition all sources of variation, differences among offspring appeared during germination, rather than during later development. Seed mass, cross type, and sex of maternal parent all significantly affected the likelihood of germination; however, they had decreasing predictive power, respectively. Inbreeding depression in Silene vulgaris may help maintain gynodioecy; however, the pleiotropic effects of both nuclear and cytoplasmic genes for sex expression also may affect fitness and the maintenance of females. THE TERM "gynodioecious" was used by Darwin (1877) for Thymus serpyllum to describe the occurrence offema1es and hermaphrodites within the same population of a plant species. Since that time, many hypotheses have attempted to explain the occurrence of two dif-I

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