Many people wonder whether a cashew is botanically a nut or a fruit. While commonly referred to as a nut, its true botanical identity is more complex than its everyday classification suggests. Understanding the precise botanical definitions of nuts and fruits helps to clarify the cashew’s place in the plant kingdom.
Botanical Classifications
Botanically, a fruit is the mature ovary of a flowering plant that contains seeds. Fruits are the primary means by which flowering plants disperse their seeds. They can be fleshy, like berries and drupes, or dry, such as nuts and grains.
A true nut, in botanical terms, is a specific type of dry fruit characterized by a hard, woody pericarp (fruit wall) that encloses a single seed and does not open at maturity. Examples of true nuts include acorns, chestnuts, and hazelnuts.
A drupe, also known as a stone fruit, is a fleshy fruit where an outer skin and a fleshy middle layer surround a hardened inner layer, or pit, which encloses a single seed. Peaches, cherries, olives, and mangoes are common examples of drupes.
A seed is the reproductive structure of a plant, containing an embryo and stored nutrients within a protective outer coat. Seeds develop from fertilized ovules and are crucial for the plant’s life cycle, enabling germination and growth into new plants.
The Cashew’s True Botanical Identity
The cashew (Anacardium occidentale) presents an interesting case that challenges common perceptions. The part typically consumed, often called the “cashew nut,” is botanically the seed. This seed is enclosed within a kidney-shaped structure that develops from the cashew flower.
This kidney-shaped structure is the true fruit of the cashew tree, classified as a drupe. The edible cashew kernel is the seed found inside this drupaceous fruit. The shell surrounding this seed contains a caustic resin, which is why cashews are always sold shelled after processing.
The large, fleshy, pear-shaped structure to which the true cashew fruit is attached is known as the cashew apple. Botanically, the cashew apple is not a true fruit developing from the ovary, but rather an “accessory fruit” or “pseudofruit.” It develops from the enlarged pedicel and receptacle of the cashew flower.
Why Cashews Are Misclassified
The common misclassification of cashews stems from the difference between botanical definitions and culinary usage. In everyday language, the term “nut” broadly refers to any edible kernel enclosed within a hard shell, regardless of its botanical origin. This culinary classification prioritizes texture and usage over strict biological criteria.
Many items commonly called “nuts” in the kitchen, such as almonds, walnuts, and pistachios, are also not botanically true nuts; they are seeds from drupes, similar to cashews. Peanuts, for instance, are legumes, belonging to the pea family. This discrepancy highlights how culinary terms often group foods based on shared characteristics like taste, texture, and application in cooking.
Therefore, while a cashew is treated as a nut in the culinary world, its botanical identity is that of a seed from a drupe, which is the true fruit of the cashew tree. The larger, colorful cashew apple is an accessory fruit. This distinction underscores the nuanced nature of botanical classification compared to common linguistic conventions.