Many varieties of maize are grown for dried, fully mature seed, which is eaten as a grain, but sweet corn is picked before the seeds mature fully, before its sugars convert back into starch. This is why fresh corn must be eaten fairly quickly after harvest, before it degrades and becomes starchy.
The precursor to the modern Brussels sprout were likely grown in ancient Rome, and today’s vegetable was perfected and popularized as early as the 13th century, in Belgium, which explains their common name. By the mid-16th century, they were being cultivated in the Netherlands and other parts of Europe.
Broccoli has quite a few close relatives and variations, and these are designated in botany by the use of “cultivar groups.” Kale and collards, Chinese broccoli, cauliflower, cabbage, Brussels sprouts, and kohlrabi all share the Latin name B. oleracea, but belong to different groups within that single species. Broccoli itself has several varieties: The most common you’re likely to see in grocery stores is called Calabrese in the UK, and just “broccoli” here in North America.
Many people in North America think of kohlrabi as being a distinctly European vegetable, but it is actually a staple ingredient in many international cuisines. It is has been a popular crop, for instance, in Northern India and Kashmir since the 1600s.
Archaeological evidence suggests peas were grown as food crops in Neolithic Turkey, Syria, and Jordan, and in the Nile valley in Egypt as early as 4500 BC. Dried peas remained an important foodstuff in Europe into the Middle Ages, but some time in the late 1600s eating green peas (as we do today) became a culinary fad in France and England.