The history of broccoli is pretty neat. It's earliest ancestor was originally from the Mediterranean region, and clutivated by the Greeks at about 650 B.C. and looked more like leafy cabbage than broccoli. It was later cultivated in various forms, near coastal regions, exposing the plants to salt spray. This caused it to develope a thick waxy layer, that is still shown in the plant today. The broccoli plant, that we know today, didn't originate until the middle of the 1500's where it consists of a large, tasty, cluster of flower buds (which will blossom yellow if not harvested early enough).
Economic Botany: Plants in our world, 3rd ed. Simpson and Ogorzaly
McGraw Hill Publishing, 2001.
Seeing as how John switched hosts, and is in the process of redoing the site, I have been given webspace, yet again, for the never ending crusade to educate the world about plants. As I just got it today, I am still working things out here, so I'll start out with a pretty easy, but still interesting, fact about plant usage.
On this planet, there are about 300,000 species of edible plant species, and historically, only 2,500 species have been consumed fairly regularly. Of these 2,500 species, only 150 of them are eaten in the modern world. This selection of plants has thinned even more, as people started to further alter certain plant species to become more palatable, to about 20 species of agricultural importance (this includes corn, rice, wheat, soybeans, and apples, just to name a few).
Unless otherwise stated, all of these plant facts will be obtained from :
Economic Botany: Plants in our world, 3rd ed. Simpson and Ogorzaly
McGraw Hill Publishing, 2001.