My contact information is incorrect and I haven't been able tpdate it. Apios Americana is not the same as dioscorea. See www.groundnutgardens.com re: information on Apios. I bought Cinnamon Vine, Chinese mountain yam, from www.raintreenursery.com. Eric Toensmeier, in his Perennial Vegetables, states that most D. Japonica in the us is mislabeled and not true Jinenjyo at all. Would be interesting to see if you find a source.