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
Bok Tower Gardens only. To make an appointment, the Bok Tower librarian should be contacted. The Chao Research Center Archives was formed in 2008, after a generous donation made by the Ting Tsung and Wei Fong Chao Foundation. With this donation, space was made available on the second floor of the Singing Tower to accommodate a growing need for delicate archival documents. The Chao Research Center Archives stores the official archives of Bok Tower Gardens along with other significant collections. These significant collections include the Nellie Lee Bok Collection, American Foundation Collection, and Edward Bok Newspaper Scrapbook Collection. The Nellie Lee Bok Collection