Carpels

Carpels are the female reproductive units of flowering plants (angiosperms). A flower may have one or more carpels, and together they form the gynoecium, the innermost reproductive whorl. Each carpel typically consists of stigma, style, and ovary. The stigma is the receptive surface for pollen, the style elevates the stigma, and the ovary contains ovules, which are attached to the placenta or to the ovary wall depending on the species.

After fertilization, the ovules develop into seeds and the carpel wall commonly becomes the pericarp, contributing to the fruit’s structure. The pattern of carpels can be syncarpous, meaning they are fused into a single, compound ovary, or apocarpous, meaning the carpels remain distinct. The chambers within the ovary are called locules, often produced by the fusion of carpels. A single carpel yields a simple gynoecium, while multiple carpels can form various configurations around the floral axis.

Carpel development begins from carpel primordia on the floral meristem and typically involves the fusion of leaf-like structures that enclose the ovules. The arrangement and number of carpels are important diagnostic features in plant taxonomy and are used to distinguish genera and species in many angiosperm groups.

Evolutionarily, carpels are thought to have arisen from leaf-like structures that folded and fused to enclose ovules, a transition associated with efficient protection of seeds and directed dispersal in flowering plants.