How do oranges, lemons, and grapefruit differ from other berries?

Oranges, lemons, and grapefruit are botanically classified as a specialized type of berry known as a hesperidium.12

While they share the fundamental characteristics of berries—being simple, fleshy fruits derived from a single ovary—they differ from other berries in the following ways:

• Leathery Rind: Unlike many common berries that have a thin or soft skin, citrus fruits possess a distinct, leathery rind studded with oil glands.12
• Internal Structure: The interior of a hesperidium is divided into segments that are packed with tiny, juice-filled vesicles.1

In contrast, other berries typically have a more uniform fleshy interior where the middle and inner layers of the fruit wall are not as distinctly specialized as the juice-filled segments found in citrus. Because of these unique structural adaptations, citrus fruits are categorized separately from other fleshy berries within botanical classification systems.23