The small, yellow specks embedded in the outer surface of a strawberry are frequently mistaken for seeds, but they are actually tiny, individual fruits called achenes. This common confusion stems from the strawberry’s unique botanical structure, which places the true reproductive part on the exterior of the sweet, fleshy portion we consume. Understanding the precise dimensions and identity of these achenes helps to clarify the complex biology of this popular fruit.
The Precise Measurement
The achene of a strawberry is remarkably small compared to the fruit we eat. A typical, fully developed achene measures approximately 1.5 to 2.5 millimeters in length and 1 to 1.5 millimeters in width, creating a teardrop or ovoid shape.
To visualize this size, an achene is comparable to a grain of sand or a poppy seed, though slightly more elongated. Achenes collectively make up only about one percent of the strawberry’s total fresh weight. An average medium-sized strawberry contains between 150 and 300 achenes on its surface.
Botanical Identity of the Strawberry Achene
The structures commonly called seeds are botanically defined as achenes, which are the strawberry plant’s true fruits. An achene is a type of dry, single-seeded fruit where the single seed is tightly encased by the hardened ovary wall. This structure is similar to the hull of a sunflower seed, which also protects the true seed inside.
The red, juicy part of the strawberry that is usually eaten is technically not the fruit, but rather the enlarged receptacle, which is the swollen part of the flower stem. This botanical distinction classifies the strawberry as an “accessory fruit” or “pseudocarp.” The achenes are scattered across the exterior of this fleshy receptacle, a structure unique among common fruits.
Achene Function and Propagation
Each achene contains the genetic material necessary to grow a new strawberry plant through sexual reproduction. The plant also uses a second, more common method of multiplication: specialized horizontal stems called runners, which are a form of asexual propagation. Growing new plants from achenes is reserved for breeding programs or cultivating new varieties, as it allows for genetic mixing.
For an achene to germinate, it requires cold stratification to break its dormancy. This chilling period simulates winter conditions, involving temperatures between 34 and 40 degrees Fahrenheit for two to four weeks. Once this requirement is met, the achenes can be sown on the surface of soil, as they also need light to begin germination. This method is often slower and yields plants that are not genetically identical to the parent, unlike the clones produced by runners.