When the main axis of the inflorescence extends continuously and flowers are present laterally on the floral axis, the inflorescence is said to be racemose. Flowers are arranged in an acropetal arrangement.
Cymose: The main axis of the inflorescence does not grow continuously in the cymose kind of inflorescence. On the main axis, a flower is present at the end of the main axis. The blooms are borne in a basipetal (or bottom-up) fashion. Growing along the main axis is restricted.
Cymose inflorescences are classified into four categories:
Helicoid: Lateral branches develop on the same side, resulting in the formation of a helix, as in Begonia and Heliotropium are examples of such plants.
Peduncle is reduced to a circular disc in this form of arrangement, and the capitulum is shaped like a star. The older blooms appear in the centre of the disc, while the younger flowers appear on the periphery of the disc. Centrifugal arrangement is the term used to describe this. For example, Acacia and Mimosa
This is due to the fact that the main axis’ growth is restricted, and the lateral axis likewise terminates in a flower, which also limits the main axis’ growth. Flowers are present in the basipetal succession, which means that the older flowers are found terminally and the younger flowers are found at the base of the plant. It is called a centrifugal arrangement because the older flowers are arranged in the centre of the arrangement and the younger flowers are arranged on the periphery.