It’s All Mustard
Today, we connotatively view mustard as a yellow condiment we might slather on sandwiches.
It’s easy to forget that delicious spread comes from the seeds of plants known as mustards. In the grand genealogical tree, mustard plants fall into the Brassicaceae family. This demarcation not only includes mustards but also cabbages and crucifers.
That latter designation covers what we know as the cruciferous vegetables, from the Latin Cruciferae, which means “cross-bearing.” The flowers of these veggies, such as broccoli, cauliflower, Brussels sprouts, kale, and collard greens, feature four petals that form the shape of a cross.
So, though these distinct examples might seem significantly different, especially from mustard, you might easily surmise they are related since they belong to the same family. You would simultaneously be right and more right than you realize.
Some scientists call Brassica oleracea the “dog of plants.”
Why is this organism, alternately named wild mustard or wild cabbage, likened to canines? To unbury our lede, broccoli, cauliflower, cabbage, collard greens, kale, and Brussels sprouts are not just in the same family, all these well-known foods are the same species!
Just like our furry friends, who can range wildly in size, color, and shape, all these mustards and cabbages are the same species. Their variances also rose for the exact reason that different types of dogs appear dissimilar: humans.
The story begins approximately three millennia ago, in southern and western Europe. The plant pictured above, today’s star – wild cabbage/wild mustard – grew naturally along the coasts of burgeoning civilizations. Someone discovered the plant was edible, so humans started to consume the greens.
People in the Mediterranean began to fancy the leafy portions of B. oleracea. They harvested the individuals with the biggest leaves and collected their seeds. Over time, these populations artificially selected versions of the plants that flaunted large tracts of leaf. Eventually, by the fifth century BCE, this selection led to kale. Today’s hip superfood is the oldest of the bunch and the first cultivar of Brassica oleracea.
We can compare a cultivar to a breed. A cultivar is a type of plant that humans shape, though they remain members of the same species. If you want dogs with floppy ears, you can breed two dogs with floppy ears to produce (usually) another dog with floppy ears. Do it over and over again and you might have a distinctly shaped pupper. Yet, this floppy-eared dog can still procreate with other dogs. At its broadest definition, a species is a group that can produce virile offspring with each other. Kale and wild cabbage can still produce new plants, even though kale now looks completely different to the original variation of the plant.
Sometime around the first century AD, humans started to select tightly bunched leaves, referred to as terminal buds in the business. This spurred the phenotype we know as plain cabbage. Germans opted to move in another direction, favoring kale with fatter stems. The result was kohlrabi, otherwise known as turnip cabbage. Not until the 15th and 16th centuries did humans decide they enjoyed immature buds, which conjured broccoli and cauliflower (scientists are not quite sure which one came first; the current thought leans toward broccoli). By the 18th century, growers had pushed the lateral bud, assembling Brussels sprouts in the process.
These variations, with diverse tastes, consistencies, and appearances, are all the same species. Like some sort of philosophical koan, they are all unique and all the same. Brocolli is and isn’t collard greens. A cabbage is a cauliflower is a broccolini. And not.
It’s probably easier to just say they’re all mustard.
Further Reading and Exploration
Kale, Brussels sprouts, cauliflower, and cabbage are all varieties of a single magical plant species – Vox
These 6 common vegetables are actually all the same plant – Business Insider
Kale, Cauliflower, and Brussels Sprouts Are the Same Species – SciShow
The extraordinary diversity of Brassica oleracea – The Botanist in the Kitchen
Genotyping-by-sequencing of Brassica oleracea vegetables reveals unique phylogenetic patterns, population structure and domestication footprints – National Library of Medicine