• Crocus etruscus
• fruit set
• monomorphism
• seed set
• self-incompatibility

Crocus etruscus Parl. (Iridaceae) is a plant species endemic to southern Tuscany, where it grows mainly at the edge of Sub-Mediterranean deciduous forests. The species is included in the National and Global IUCN Red List with the status NT; it is also included in Annex IVb of the Habitats Directive and Annex I of the Bern Convention.
Self-incompatibility is widespread in the genus Crocus. The aims of this work are a) verify the presence or the degree of self-incompatibility in Crocus etruscus related to the variability of the stylus' length in relation with the position of the anthers; b) quantify the relationship between the mutual position of the sexual organs and reproductive fitness, through the analysis of the effect of different systems of pollination and the degree of spatial separation between sexual organs. The fitness is quantified considering the amount of fruits and seeds, and the mass of seeds produced.
The study on the species was carried out in situ, in the population of Sassetta (Castagneto Carducci, Livorno). I carried out various kind of hand pollination experiments on single individuals: selfing, spontaneous and forced, of long-styled and short-styled flowers, and all possible cross combinations; then I sampled the variability in the length of the stylus in randomly chosen individuals. On all fruits and seeds produced I calculated fruit set and seed set, and I measured the mass of seeds obtained from the different treatments, to relate with the fitness resulting from various types of pollination. Statistical analyses were performed using logistic regression, ANOVA, other statistical tests and indices such as the Self-Compatibility Index, the Selfing Rate and the Self-Incompatibility Index.
Regarding the flower morphology, the main feature is the position of the stigma, which varies seamlessly from higher to lower than the anthers, for this reason this characteristic can be defined stigma height "monomorphism"; the shorter the distance stigma-anthers, the greater the number of seeds produced. Cross-pollination between Short and Long morphs does not lead to significant differences in the amount of fruits and seeds produced. Separation between stigma and anthers results in limiting as much as possible self-pollination; the species is partially self-incompatible. The reproduction by apomixis is not possible.