An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified. The modifications can involve the length and the nature of the internodes and the phyllotaxis, as well as variations in the proportions, compressions, swellings, adnations, connations and reduction of main and secondary axes. Inflorescence can also be defined as the reproductive portion of a plant that bears a cluster of flowers in a specific pattern.
The stem holding the whole inflorescence is called a peduncle and the major axis holding the flowers or more branches within the inflorescence is called the rachis. The stalk of each single flower is called a pedicel. A flower that is not part of an inflorescence is called a solitary flower and its stalk is also referred to as a peduncle. Any flower in an inflorescence may be referred to as a floret, especially when the individual flowers are particularly small and borne in a tight cluster, such as in a pseudanthium. The fruiting stage of an inflorescence is known as an infructescence.
Inflorescences are typically of two types, they are...
1. Indeterminate inflorescence (Racemose)
2. Determinate inflorescence (Cymose)
1. Indeterminate inflorescence (Racemose)
The apical meristem of the terminal bud from which the inflorescence is initiated remains active as the inflorescence develops and all of the flowers from lateral buds, inflorescence of unrestricted growth result. These are often elongated inflorescence with a central rachis or axis. The oldest flowers or buds are those located farthest from the terminal bud or at the base or outside of the inflorescence.
ii. Determinate inflorescence (Cymose)
Soon after the inflorescence begins development the terminal bud differentiates into a flower. This terminates future growth in length and additional flowers can only develop from buds already formed or from lateral growth. It is an inflorescence of limited growth. The oldest flower is located at the end of the stem or in the center of the inflorescence.
