Broccoli is a member of the mustard family, descended from the wild cabbages. Broccoli's name comes from the Italian "brocco," meaning "sprout" or "shoot," which comes from the Latin, "brachium," meaning "arm" or "branch." Leaves are eaten as much as flowers. It is native to the Mediterranean and was originally eaten for its stems, and later bred to have large, delicious flowers. Cauliflower was a development of broccoli during this period of improvement.

In Elizabethan England, the term "cabbage" applied only to the compact heart or head of the cabbage plant, and the entire plant was known as cabbage-cole or colewort. The English, upon first being introduced to broccoli by the Italians sometime around 1700 AD, called it Italian asparagus and did not recognize it as being the same Genus as cabbage. In England, "broccoli" now refers to "cauliflower."

The Italians also brought broccoli to North America (by 1806), but broccoli did not become popular in America until the 1920's due to the successful marketing of the D'Arrigo Brothers Company (which farmed broccoli). By the 1930's it was a staple vegetable of the American diet. Demand for broccoli lagged behind cauliflower until after the Second World War, when Americans, returning from Europe and the European broccolis, demanded the vegetable at home.

There are two major types of broccoli: those which are grown for heads of flowers, and those which are grown for heads of flowers and their leaves. It was out of the first type that cauliflower was bred: the broccoli flower was made larger and white. Cauliflower was very popular in Greece, but did not become popular in the rest of Europe until Louis XIV favored the vegetable. Cauliflower was introduced into England at the same time as broccoli by the Italians and the French, and by 1633 was known widely as Cole Florie (cabbage flower) or Coliflorie or Cyprus Coleworts: the name of cauliflower comes from the French term, "cabbage flower" (choufleur). This sounded too much like "shoe flower" in English to be marketable, and "Cauliflower" was adopted instead. Cauliflowers were introduced to North America at the same time as broccoli.

There are dozens of types of both broccolis and cauliflowers with variations in color (from purple to orange) and size. By far the most popular varieties of broccoli are the green flowered, and the most popular cauliflowers are the white headed varieties.