inflorescence

The arrangement of more than one flower on the stem, together with any associated structures, such as bracts. Development is triggered by changes in light duration or temperature, and is probably controlled by hormones. The vegetative growth of the plant may cease with production of the inflorescence, or may continue afterwards; this is of significance in some crop plants where yield, ripening, and harvesting techniques are important. The type of inflorescence is often significant as a diagnostic character in recognizing plant families. Basic types are distinguished by the different branching patterns and by the positions of the oldest and youngest flowers. In cymose inflorescences, the meristem of the main axis differentiates into a flower with new growth coming from a lateral branch (monochasia) or branches (dichasia) which in turn are terminated by a flower. In racemose [rasimohz] inflorescences, the main axis continues to grow, flowers being formed below the tip.

An inflorescence is a group or cluster of flowers on a branch of a plant. In botany, the term refers to the way individual flowers are arranged on the axis (floral stem). An inflorescence is said to be indeterminate if the number of flowers on an axis may increase after the first flower opens, even while others are opening, and determinate if the number of flowers on an axis cannot increase after the first flower opens. In indeterminate inflorescences, the most proximal flowers (ie. in the case of determinate flower clusters, the most distal flowers (ie. Following is a list of terms used to describe inflorescences with links to examples:

A corymb is a racemose (see raceme) inflorescence that is flat-topped or convex because the outer pedicels are progressively longer than the inner ones (see also umbel). A head is a dense, indeterminate inflorescence of sessile or subsessile flowers crowded on a compound receptacle; A panicle is a branched, indeterminate inflorescence with pedicellate (having short floral stalks) flowers on the secondary branches. A raceme is an unbranched, indeterminate inflorescence with pedicellate (having short floral stalks) flowers along the axis. A spadix is a stalk with flowers densely arranged around it, enclosed or accompanied by a spathe. A spike is an unbranched, indeterminate inflorescence with sessile flowers arranged along the axis.

In some plants, especially those in family Proteaceae, the inflorescence may be a complex structure consisting of many smaller inflorescences. For example, Banksia flowers occur in pairs, which are then clustered together to form a dense head.

In some plants, the structure that holds the flowers together persists until fruit is formed, resulting in a fruiting structure in which individual fruit are embedded.