Madeira Vine (Anredera cordifolia), 川七 or 藤三七.
Far more valued in the past than the present, the plant has quite a history. Anredera cordifolia is native to the dryer areas of South America; not only are the underground roots (actually rhizomes) edible but the evergreen leaves as well. Leaves and tender stems are eaten raw, boiled, stir-fried with sesame oil and ginger, or in soups. 
 
Madeira vine leaves can be cooked like spinach and are highly nutritious
Madeira vine roots (rizomes) can be baked like potato
Madeira vine bubils (the aerial seed-ish things) are used extensively in Chinese medicine as an anti inflammatory, anti ulcer and liver protectant.