Corymb

Corymb is a term used in botany to describe a type of flower cluster (inflorescence) where the lower flowers have longer stalks (pedicels) than the upper ones, making the top of the inflorescence more or less flat, or slightly convex. This arrangement allows flowers at different levels to reach a similar height, presenting a visually appealing display that is advantageous for attracting pollinators. Corymbs can be found in various plant families, including the Rosaceae (Rose family), Apiaceae (Carrot family), and Brassicaceae (Mustard family).

Characteristics

In a corymb, the pedicels of the lower flowers are elongated so that all flowers approximately reach the same level. This contrasts with a raceme, where the flowers are arranged along the central stem without such adjustment in pedicel length, resulting in a more elongated shape. Corymbs can be simple or compound. In a simple corymb, each flower is directly attached to the main axis. In contrast, in a compound corymb, there are secondary axes (branches) on which the flowers are borne.

Types of Corymbs

• Simple Corymb: A single axis where flowers are attached at different points along it, with lower flowers having longer pedicels.
• Compound Corymb: Consists of several branches, each forming a simple corymb, leading to a broader and more complex structure.

Examples

Some common examples of plants with corymb inflorescences include:

• Yarrow (Achillea millefolium)
• Hawthorn (Crataegus)
• Elderberry (Sambucus)

Ecological Significance

The corymb structure is particularly effective in attracting pollinators. By presenting flowers at a uniform height, plants can more easily catch the attention of pollinating insects and birds. Additionally, the flat or slightly convex top of a corymb provides a convenient landing platform for pollinators, facilitating pollination.

See Also

• Inflorescence
• Raceme
• Umbel
• Spike (botany)