Article

The simple flowers of the Umbelliferae, organized in a characteristic inflorescence, appear unspecialized for pollination by a large variety of insect taxa. However, isolating mechanisms exist and protandry is widespread. Dichogamy is often related to petal size, the conspicuousness of the umbel, the presence and number of functionally male flowers, and pollen-grain size. This complex character syndrome is related to the breeding system and to the degree of inbreeding or outbreeding. Although the flowers show few features useful for the taxonomist, a wide array of valuable structures occur in the fruits. Many of these appear to have evolved for mericarp dispersal, both by wind and by animals. Heterocarpic taxa exist in several species, where spiny mericarps appear to serve for the spreading of the species, while non-spiny, tuberculate ones maintain the existing population.