Peduncle

When you cut flowers for a bouquet, you are generally cutting the peduncle. Peduncles are simply flowering stems, but they may surprise you. 

Johnny-jump-up

Artichoke bud and peduncle (Jamain) CC BY-SA 3.0

Peduncles and inflorescences

When clusters of flowers grow together, it is called an inflorescence. An inflorescence is also supported by a peduncle, but the stems within the cluster, supporting the florets, are called pedicels, or strigs. For example, clusters of grapes grow on a peduncle, while the individual grapes hang from pedicels.

Peduncles can occur in plants without stems, they may continue to grow indefinitely, and some peduncles grow underground.

The peduncle of a simple flower is easy to recognize. It is the classic stem you hold, cut, or put into a vase to admire. Its job is to support the flower. An artichoke stem is a peduncle, and for the same reason.

Agave peduncle (JonRichfield) CC BY-SA 3.0

Peduncles as scapes

The leafless flowering stems of bulbs, onions, and garlic are called scapes. Scapes are a type of peduncle made up of a single internode. Internodes are the spaces along a stem between leaf nodes.

Onions preparing to flower

Accrescent peduncles

While many plants are hardwired to stop growing once they reach a certain size, other plants, such as the mighty redwoods, continue growing throughout their lifetime. In other cases, certain parts of a plant will continue to grow larger. These plants are called accrescent. In some cases, only the peduncle is accrescent, and then only until the flower reaches maturity

Echeveria elegans in bloom

Acaulescent peduncles

Some plants don’t have stems. Those plants are said to be acaulescent. Many acaulescent plants, such as succulents, still put out flowers on long stem-like structures. Those structures are peduncles.

Peduncles as pegs

In most cases, the peduncle grows upward, toward sunlight. In other, more rare cases, the peduncle, or peg, pushes its way underground to produce its fruit out of sight. This method is called geocarpy. Peanuts are an example of geocarpy.

Peanut pegs penetrating the ground (Alain Busser) CC BY-SA 1.0

Now you know.