It is often confused with a spike when the pedicels are small and inconspicuous. Heads are a diagnostic feature of the sunflower family (Asteraceae), examples of which are daisies, chrysanthemums, and sunflowers.Ī panicle has a branched floral axis (rachis), which may re-branch prior to bearing flower pedicels (described some times as a compound raceme).Ī raceme has pedicellate flowers borne on an elongate rachis. Examples include hydrangea and hawthorn.Ī head, or capitulum, is a tight cluster of sessile flowers (flowers with no pedicel) borne on a flattened or short stemtip (receptacle). The pedicels of flowers are attached along the length of the peduncle. This inflorescence is typical of trees such as oaks, hickories, and birches.Ī corymb is a flat-or rounded-top inflorescence. The flowers are typically unisexual and are hidden by bracts.
Dissection may reveal the presence of minute, and possibly branched, pedicels. Any vascular plant taxonomy text will provide a more comprehensive list.Ī catkin (also known as an ament) is a spikelike inflorescence. The following descriptions of inflorescence types represent most of the basic types. This type of inflorescence is said to be determinate and is best represented by a cyme (defined below). If the apical meristem quickly matures into a flower, it can no longer grow in length, and the inflorescence exhibits a limited growth pattern. Araceme (defined below) is a typical indeterminate inflorescence. If the growing tip of the stem (apical meristem) continues to grow and produce new flowers as it elongates, the inflorescence is said to be indeterminate. The form of an inflorescence, however, is determined largely by two patterns of development. Parameters used to classify basic inflorescence types includeīecause the inflorescence type of a given species may result from evolutionary reduction, classification schemes are typically artificial and do not reflect evolutionary significance. A rachis is the main branch or axis within a complex inflorescence. Apeduncle is a stalk of a solitary flower or of an inflorescence. A pedicel is a stalk supporting a single flower of an inflorescence.
#Cyme flowers series
Abracteole is a bract that is much smaller in size.Īn involucre is a series of bracts or bracteoles subtending a flower or inflorescence. Abract is a small or modified leaf immediately beneath a flower or inflorescence. An axillary bud occurs in the angles between a stem and a leaf petiole. The following terms, some of which already have been introduced, are features or structures that are used to classify inflorescences. In spite of these confusing elements, most common inflorescence patterns can easily be recognized. This type of inflorescence is associated with daisies and asters (Asteraceae) and is often mistaken for a single flower by those unfamiliar with flower and inflorescence structure. If clusters of many reduced flowers are borne on very short stems, the resulting aggregation may superficially resemble a single flower. Clusters of flowers issuing from such spurs may resemble inflorescence types, although the flowers are solitary.įlowers may be complete, possessing all four sets of floral appendages, or they may be reduced to as little as one set of reproductive structures (stamen or pistils). The latter pattern is observed in many fruit tree species, such as apples and pears, where the fruit is supported by short, modified branches called spurs. They may grow much more slowly than branches that support only vegetative structures. Sometimes woody branches that support flowers are modified. The determination of whether subtending leaflike structures are leaves or bracts may establish a flower as solitary or as part of an inflorescence. If a second, considerably smaller set is present, its component parts are termed bracteoles. If leaves subtending the flower are much smaller or distinctly different from regular leaves, they are referred to as bracts. Leaves that immediately subtended the reproductive structures became the sterile parts of the flower (petals and sepals) and are typically more leaflike as distance from the apex increases. These reproductive structures became the pistils and stamen of the flower. It generally is accepted that the flower arose as a modified stem tip that bore male and female reproductive structures at its apex. An examination of the evolutionary development of the flower and the inflorescence provides some insight into the problem. It is not always easy to distinguish between solitary flowers and an inflorescence.
Most schemes that define inflorescence types separate solitary flowers from flower clusters and stipulate that an inflorescence is a cluster of two or more flowers. The term "inflorescence" refers to the arrangement of flowers on a floral axis.