Amaryllidaceae, having common name(s) associated with the genus; Milk Lily, Orinoco Lily, Milk and Wine Lily.
ADDED IN 2019! I'm not certain I have the correct name, but I won this variety in a raffle, donated by Dave Lehmiller. It performs very well for me here in Zone 6. Ht. 30-36 inches. Hardy in zones 6, 7, 8, 9, 10.