The question of whether beets are part of the Brassica group is a common one, largely because both are widely consumed root and leaf vegetables with a similar presence in the produce section. The definitive botanical answer is that beets are not brassicas. This distinction reflects fundamental differences in their evolutionary history, physical structure, and internal biochemistry.
The Definitive Answer: Botanical Classification of Beets
Beets, scientifically known as Beta vulgaris, belong to the genus Beta and the plant family Amaranthaceae. This places them in a distinct botanical grouping from the Brassica family. The Amaranthaceae family is diverse, encompassing many other well-known edible plants, including spinach and quinoa.
The cultivated forms of Beta vulgaris are varied, including the familiar garden beet (or beetroot), the leafy vegetable chard, the fodder beet known as mangel-wurzel, and the sugar beet. All these forms share a common ancestry in the wild sea beet (Beta vulgaris subsp. maritima), which grows along the coasts of Europe and the Mediterranean.
Understanding the Brassicaceae Family
The Brassica group belongs to the Brassicaceae family, which is commonly referred to as the mustard family or the cruciferous family. Well-known examples that are true brassicas include broccoli, cauliflower, cabbage, kale, Brussels sprouts, and mustard greens.
The common name “cruciferous” comes from the Latin word crux, meaning cross, referring to the distinctive shape of their flowers. This four-petaled arrangement is a defining physical characteristic that sets them apart. These plants are also grouped together because they share similar growing requirements and are susceptible to a common set of insect pests and diseases.
Key Differences That Separate the Groups
The separation of beets and brassicas is rooted in two significant biological distinctions: flower morphology and chemical composition. The flowers of Brassicaceae plants possess four free petals arranged in a distinct cross shape, a feature absent in the beet family. In contrast, the flowers of Beta vulgaris are small, typically green, and often inconspicuous, growing in clusters on a tall, branched stem in the plant’s second year.
The most fundamental difference lies in their chemical markers, which influence their flavor and color. Brassicas are characterized by sulfur-containing compounds called glucosinolates, which are responsible for the pungent, slightly bitter flavor in vegetables like horseradish and mustard. When the plant tissue is damaged, these compounds break down into spicy isothiocyanates, a chemical defense mechanism.
Beets and other Amaranthaceae plants, however, produce nitrogen-containing pigments called betalains. These water-soluble compounds create the deep red-violet color in garden beets (betacyanins) and the yellow-orange hues in certain varieties (betaxanthins). Plants that produce betalains do not produce the common red and blue pigments known as anthocyanins, which are found in almost all other flowering plants. This unique chemical pathway confirms beets are botanically separate from the brassicas.