cyme

A cyme is a type of inflorescence in flowering plants distinguished by its determinate growth pattern, where the terminal flower blooms first and the main axis ends growth. After the terminal flower forms, subsequent flowers develop from lateral, short axes or branchlets, producing a succession of blooms from the ends of those side branches. Because the oldest flower is at the apex, cymes are considered determinate, in contrast with racemes and other indeterminate inflorescences.

Cymes are commonly classified into two main forms: monochasial and dichasial. Monochasial cymes have a single side branch that produces all subsequent flowers. The pattern can be helicoid, where the lateral axis continues in a helical sequence, or scorpioid, where the development curves into a tail-like coil; the scorpioid cyme is characteristic of many members of the Boraginaceae. Dichasial cymes feature two opposite lateral branches arising from the main axis, each terminating in a flower; further flowers may develop to produce a forked, two-armed pattern.

In practice, cymes are found across diverse dicotyledonous groups and can vary considerably in size and density, from compact heads to more elongated clusters. They are often discussed in relation to other inflorescence types, with the key distinction being determinate growth in cymes versus indeterminate growth in racemes and related forms.

Examples of cymose patterns are noted in several plant lineages, including the characteristic scorpioid cymes of Boraginaceae, illustrating the diversity and recognizability of this inflorescence type.