Brassicaceae greens, Savoy, kohlrabi, and gai lan ("Brassica oleracea"), turnip, napa cabbage, bomdong, bok choy and rapini ("Brassica rapa"), rocket salad/arugula ("Eruca sativa"), garden cress ("Lepidium sativum"), watercress ("Nasturtium officinale") and radish ("Raphanus") and a few spices like horseradish ("Armoracia rusticana"), "Brassica", wasabi ("Eutrema japonicum"), white, Indian and black mustard ("Sinapis alba", "Brassica juncea" and "B. nigra" respectively). Vegetable oil is produced from the seeds of several species such as "Brassica napus" (rapeseed oil), perhaps providing the largest volume of vegetable oils of any species. Woad ("Isatis tinctoria") was used in the past to produce a blue textile dye (indigo), but
Vegetable oils as alternative energy prices is largely attributed to biofuel demand. Much of the fuel price at the pump is due to fuel tax. If you buy vegetable oil at the grocery store it does not have such high taxes. So at times people have bought vegetable oil at the store for their cars because it was cheaper. They did this in spite of the fact that packaging by the gallon adds to the cost and it was illegal to use in a car since no fuel tax had been paid on it. Since vegetable oil (even as biodiesel) does not contribute to greenhouse