Cabbage is a common, inexpensive vegetable found on dinner tables across the globe. As a member of the diverse Brassica genus, it is grouped with other leafy greens and cruciferous vegetables. The confusion often stems from its distinct, tightly packed structure, which looks unlike the simple leaves of lettuce or the stems of celery.
Cabbage’s Botanical Classification
The edible portion of a cabbage plant is botanically classified as a large vegetative bud, also known as a terminal bud. This dense structure is not a single, giant leaf but rather a cluster of many modified leaves. These leaves are tightly overlapped and pressed together, which gives the cabbage head its characteristic firmness and weight. The plant itself is a cultivar of the species Brassica oleracea, specifically the Capitata Group. This species is a biennial, meaning it typically completes its life cycle over two years, though it is cultivated as an annual crop for its head in the first year. The head is essentially the plant’s attempt to store food and protect the growing point, or meristem, within the leaves.
The Unique Formation of the Cabbage Head
The formation of the dense cabbage head is a result of selective breeding that altered the plant’s natural growth pattern. In a non-heading plant, the stem would elongate between the leaves, allowing them to spread out in a loose rosette. In cabbage, however, the central stem, which forms the small core at the base, remains extremely short, preventing the leaves from separating. As new leaves develop, they are forced to grow inward and overlap tightly, a process known as “cupping.” The outermost leaves, often called wrapper leaves, are exposed to sunlight and are typically greener, while the inner leaves remain blanched and pale due to light exclusion.
Cabbage’s Relation to Other Edible Plant Parts
The Brassica oleracea species has been selectively bred to exaggerate different parts of the plant, resulting in a wide array of vegetables. Cabbage’s identity as a terminal bud is clarified when compared to these relatives:
- Kale and collard greens were bred for their large, loose, edible leaves, representing a form closest to the wild ancestor.
- Brussels sprouts are axillary buds that form along the side of the main stem, not the terminal bud.
- Broccoli and cauliflower were bred for their edible flower structures. Broccoli is consumed as immature flower heads and stems, while cauliflower is an undeveloped cluster of flower buds.
- Kohlrabi is a modified stem, which is the swollen, turnip-like globe above the soil line.