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.