Manihot esculenta, Manihot utilissima.
Tuber skin and thick brown woody appearance or dark brown inside which meat is white.
Your oil consumption is highly toxic and even fatal because of its content so that cyanogenic to consume should be cooked for a long time. The flour is obtained by grinding the tuber is called tapioca. It is used very extensively in Latin American cuisine (boiled or fried like potatoes, ground into flour for dessert even sweeter with honey).