The turnip, a common root vegetable, belongs to the genus Brassica and is categorized within the Brassicaceae family of flowering plants. This classification places the turnip alongside many other familiar vegetables consumed globally, all sharing distinct biological markers that define their family lineage.
What Defines the Brassicaceae Family
The plant family Brassicaceae is widely known by its common name, the mustard family, or by its older, equally accepted name, Cruciferae. The name Cruciferae, which means “cross-bearing,” refers directly to the distinctive structure of the flowers shared by these plants. Each flower has four petals arranged in the shape of a cross, a defining visual characteristic of the family.
These plants, which are predominantly herbaceous, also share a specific chemical profile that contributes to their flavor. They contain sulfur-containing compounds called glucosinolates, which are responsible for the pungent, sometimes peppery, taste found in many mustard family vegetables. The presence of these compounds is a reliable biochemical marker for plants within the Brassicaceae family. This large family encompasses approximately 338 genera and over 3,700 species, found mainly in temperate regions worldwide.
Turnips and Their Common Botanical Relatives
The turnip belongs to the genus Brassica, which contains many of the world’s most significant agricultural food crops. The diversity within this genus is remarkable, as different varieties have been selectively bred to emphasize various parts of the plant. Many familiar vegetables, including cabbage, kale, broccoli, and cauliflower, are actually different cultivated forms of the single species Brassica oleracea.
These relatives are grouped by the parts of the plant developed for consumption:
- Heading varieties like cabbage.
- Flowering varieties like broccoli and cauliflower.
- Leafy varieties like kale and collard greens.
Other prominent members of the mustard family that are not Brassica oleracea include radish (Raphanus sativus) and horseradish (Armoracia rusticana).
Specific Classification of the Turnip
The turnip itself has the specific scientific name Brassica rapa. More precisely, the common turnip is classified as Brassica rapa subspecies rapa, which refers to the variety grown for its rounded, fleshy taproot. This swollen root is the primary edible component, but the plant’s leafy tops are also commonly consumed as turnip greens.
The species Brassica rapa is highly diverse and includes several other distinct cultivated forms besides the turnip. For instance, Chinese cabbage, bok choy, and rapini, also known as broccoli rabe, are all varieties within the same Brassica rapa species. This highlights that classification often groups plants that look visually different but share a recent common ancestor.