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
Fat choy Fat choy Fat choy (; "Nostoc flagelliforme") is a terrestrial cyanobacterium (a type of photosynthetic bacteria) that is used as a vegetable in Chinese cuisine. When dried, the product has the appearance of black hair. For that reason, its name in Chinese means "hair vegetable." When soaked, fat choy has a soft texture which is like very fine vermicelli. Fat choy grows on the ground in the Gobi Desert and the Qinghai Plateau. Over-harvesting on the Mongolian steppes has furthered erosion and desertification in those areas. The Chinese government has limited its harvesting, which has caused its price to increase.