A pome is a fleshy fruit that develops primarily from structures outside the flower’s ovary. This unique development process distinguishes it from many other common fruit types, where the edible portion is derived solely from the ripened ovary wall. The term originates from the Latin word pōmum, meaning “fruit” or “apple.” Pomes are characterized by a central core containing the seeds and an expansive, surrounding layer of edible tissue that forms from the lower parts of the flower.
Defining the Pome’s Structure
The anatomy of a pome is defined by its distinct internal components, which form a layered structure. The outermost part, the skin, is the exocarp, which covers the thick, fleshy layer that is consumed. This fleshy portion does not originate from the ovary, but rather from the receptacle and the hypanthium, which is a cup-like structure formed by the fused bases of the sepals, petals, and stamens.
Beneath the edible flesh lies the central core, which contains the true fruit parts derived from the flower’s ovary. This core is composed of several carpels, the female reproductive organs of the flower, which are fused together. Each carpel is lined by a tough, parchment-like material called the endocarp, which creates the protective chambers that give the core its characteristic texture. The seeds, often called pips, are housed securely within these leathery or sometimes stony endocarp chambers.
The shriveled remnants of the sepals and stamens are often visible at the end of the fruit opposite the stem attachment, a telltale sign of their unique floral origin. This presence indicates that the ovary was situated below the other flower parts, a position botanists often describe as an inferior ovary.
The Rosaceae Family and Key Pome Fruits
Nearly all fruits classified as pomes originate from the diverse plant family Rosaceae, commonly known as the rose family. Within this large family, the pome-producing plants belong to the Malinae subtribe, which was traditionally known as the Maloideae subfamily. This taxonomic group is distinguished by a particular floral structure that leads to the development of this specific fruit type.
The best-known examples of pomes are the apple (Malus) and the pear (Pyrus), which are cultivated globally and are the archetypal representations of this fruit category. The quince (Cydonia) is another historically important pome, recognized for its hard, fragrant fruit that is often used in preserves and jellies.
Beyond the commercially familiar types, several lesser-known fruits also share the pome classification:
- Hawthorn (Crataegus), which produces small, berry-like fruits.
- Loquat (Eriobotrya japonica), a subtropical fruit that is small, sweet, and yellowish-orange.
- Medlar (Mespilus germanica).
- Various species of serviceberry (Amelanchier).
Pome Development: Accessory vs. True Fruit
The defining characteristic of the pome is the biological mechanism by which its fleshy part forms, leading to its classification as an accessory fruit. A true fruit is defined strictly as the ripened ovary wall of a flower, which is not the case for the majority of a pome’s volume. Accessory fruits, in contrast, incorporate tissue from other flower parts besides just the ovary.
In the development of a pome, the fleshy, edible part is primarily derived from the enlarged hypanthium and receptacle. The hypanthium is a floral cup that surrounds the ovary, and as the fruit matures, this structure expands significantly to become the bulk of the fruit. This process contrasts with fruits like a cherry or plum, where the entire fleshy portion develops solely from the ovary wall.
The ovary itself develops into the central core, which is the actual true fruit portion of the pome. This true fruit is the papery or leathery structure that encloses the seeds. When consuming a pome, a person is eating primarily the swollen floral base, with the true botanical fruit confined to the less-palatable core. The inclusion of non-ovary tissue in the mature structure provides the pome its unique developmental distinction.