Broccoli belongs to the large cabbage or mustard family, scientifically known as Brassicaceae. This family encompasses a wide array of vegetables, often called cruciferous vegetables, known for their distinct, pungent flavors and numerous health benefits. They share a common ancestry and a unique chemical profile.
Defining the Brassica Family
The Brassicaceae family is characterized by plants in the genus Brassica, which includes thousands of species globally. The former name, Cruciferae, meaning “cross-bearing,” comes from the defining physical trait of its flowers. These flowers typically have four petals arranged in a cross shape, a structure that distinguishes the entire family.
Members of this group are also characterized by sulfur-containing compounds called glucosinolates. These compounds are responsible for the sharp flavor profile of the vegetables. When the plant tissue is damaged, an enzyme breaks down glucosinolates into bioactive compounds like isothiocyanates.
The Many Faces of Brassica oleracea
Broccoli’s specific classification is Brassica oleracea var. italica, meaning it is a cultivated variety of the species Brassica oleracea. This single wild species, often called wild cabbage, is the genetic ancestor of a remarkable number of morphologically distinct vegetables.
Through centuries of human intervention and selective breeding, farmers exaggerated different parts of the wild plant to create these varied forms. This process, known as artificial selection, resulted in a diverse group of crops that are all derived from the same species. The core group of vegetables derived from Brassica oleracea includes broccoli, cabbage, cauliflower, kale, Brussels sprouts, and kohlrabi.
Distinguishing Common Brassicas
The significant differences in appearance among these Brassica oleracea relatives result from breeders focusing on specific plant structures.
Broccoli
Broccoli was developed by selecting for the undeveloped flowering structure, forming the dense, edible green heads we consume. This cultivation targets the immature flower buds and the supporting stalk.
Cabbage
Cabbage was bred by selecting for a tightly compressed terminal leaf bud, which forms the dense, spherical core.
Cauliflower
Cauliflower was selected for a modification of the flower cluster, resulting in its characteristic white, compacted head, known as the curd.
Brussels Sprouts, Kale, and Kohlrabi
Brussels sprouts represent a selection for the lateral buds that form along the side of the main stalk. Kale was developed by selecting for large, tender leaves, while kohlrabi was bred for a swollen stem. These contrasting focuses illustrate the extraordinary genetic plasticity within the single species, Brassica oleracea.