Terminology of inflorescence diversity has often been used in a confusing way in the literature, partly because it was based on uncritical and outdated definitions. In particular, the terms cyme, thyrse, and panicle have been misused. Although a more critical classification worked out by several authors is available, it is unfortunately not in general use because most of the relevant publications are written in German. In addition, some terms have not been used in the same way by morphologists and developmental geneticists. The present review attempts to remedy the situation with a simple outline of a classification based on: (i) different branching patterns; (ii) differential elongation of axes of different orders; and (iii) repetition of basic ramification patterns in different ways. Racemose and cymose branching are two extreme patterns; the former with limitation of axial orders to two, the second with limitation of lateral axes of each order to two. In a branching system, a sequence of racemose → cymose and, within the cyme, of dichasial → monochasial is common, but the reverse sequence generally does not occur. Systematic and evolutionary aspects of inflorescences are briefly discussed. Branching patterns are often stable in larger clades. Inflorescences of mutants studied in developmental genetic studies are mainly altered in flower or branch numbers or relative branch length, but not in branching patterns. This is also a contribution towards the goal of a unified terminology for the different fields of biology dealing with inflorescences. Key words branching patterns, cymose, inflorescence, panicle, racemose, reproductive shoot, thyrse.Whereas flowers have been in center of interest in many branches of plant science, including morphological, developmental, functional, biological, ecological, and evolutionary aspects, inflorescences have received much less attention. Except for the studies by W. Troll and collaborators (e.g. Troll & Weber, 1953, 1955Troll, 1957Troll, , 1964Troll, , 1969Weberling, 1965Weberling, , 1989aTroll & Weberling, 1989;Weberling & Troll, 1998), no broad critical comparative morphological studies on inflorescences were undertaken in the past century. Because Troll's works were published in German, they did not get proper attention at a world scale. The most recent, but now rather dated, general treatments of morphological inflorescence classification by an author writing in English were provided by Rickett (1944Rickett ( , 1955. He used the presence or absence of terminal flowers, branching patterns, relative branch length, and the sequence of flower opening in an inflorescence as important criteria for a basic inflorescence classification. However, branching patterns and sequence of flower opening involve two very different realms of development; the first deals with initial stages of branching, the second with
