Gynobasic style is the characteristic feature of which family :

Question

Accepted Answer

The correct option is 1: Lamiaceae

A gynobasic style is a specialized morphological feature used in plant taxonomy, and it is a key diagnostic characteristic for the **Lamiaceae** family, commonly known as the mint family. The term 'gynobasic' describes a style that appears to rise directly from the base of the ovary, specifically from the center of four deeply separated, or lobed, carpels that rest upon a basal disc or thalamus. The ovary in Lamiaceae is superior and profoundly four-lobed, leading to a developmental condition where the style insertion is significantly lower than the true apex of the carpels. This unique attachment between the four lobes creates the distinct gynobasic appearance. This particular structure is evolutionarily significant because it directly dictates the final fruit form, which in Lamiaceae is typically a schizocarp that splits neatly into four separate, one-seeded nutlets or mericarps upon maturity.

The incorrect option is 2: Fabaceae

The Fabaceae family, or the legume family, is characterized by a fundamentally different gynoecium structure. The flower typically contains a simple pistil, which is derived from a single carpel. This unicarpellary ovary features marginal placentation, where the ovules are attached along the inner seam. Unlike the deeply lobed structure of Lamiaceae, the style in Fabaceae arises directly from the apex, or top, of the simple ovary. This is referred to as a **terminal** style. The characteristic fruit of this family is a legume or a pod, which dehisces (splits open) along two sutures, which is structurally incompatible with the four nutlets resulting from a gynobasic style.

The incorrect option is 3: Apiaceae

The Apiaceae family, which includes parsley, carrots, and celery, is identified by its unique schizocarpic fruit and its floral anatomy, which does not include a gynobasic style. Apiaceous plants typically have an inferior, bicarpellary ovary (composed of two fused carpels). The apex of this ovary features a pair of free styles. Critically, these styles sit atop a distinct, thickened, nectar-secreting structure called the **stylopodium**. This arrangement is entirely different from the style arising from the center of four basal lobes. The fruit splits into two dry, one-seeded mericarps, often bearing ribs, confirming its non-gynobasic origin.

The incorrect option is 4: Asteraceae

The Asteraceae family, the largest family of flowering plants which includes sunflowers and daisies, is defined by its characteristic head-like inflorescence (capitulum) and inferior ovary. In Asteraceae, the gynoecium is typically bicarpellary with a single basal ovule. The style arises from the top of the ovary and is therefore **terminal**, not gynobasic. The style often branches at the tip, forming two stigmatic surfaces, which are sometimes called style arms. The fruit is a single-seeded achene, which is often topped by a pappus. These features, particularly the inferior ovary and terminal style, completely rule out the presence of a gynobasic style as a characteristic feature of this family.