4.2. The club-like organ development
In Apiaceae, the black structures appeared as various shapes and colors in center of umbel or umbellets. It evolved many times independently in lineages of this family (Baczyński et al. 2022). The functional role of these organs studied mainly in Da. carota (e.g., Eisikowitch, 1980; Westmoreland and Muntan 1996, Lamborn and Ollerton 2000). The developmental studies in Artedia squamata L., Da. carota, Echinophora trichophylla Sm., Tordylium aegyptiacum (L.) Poir., T. cappadocicum Boiss., showed that the dark structures are not homologous to each other. In Da. carota , it initiated from a central flowers or umbellets whereas in the rest ones initiated from a naked umbel meristem (Claßen-Bockhoff et al. 2023, unpubl.). InDi. persica , the club-like organ initiates from outgrowth of a naked umbel meristem which is not homologous with an umbellet or a single flower. There is a correlation between bulging the umbel center and extant of umbellet fractionation. The center of the umbel remains naked for long time. It starts to bulge when flowers of the inner ones are initiating the floral organs.