Joe, one easy way to distinguish the two is season of bloom: Zephyranthes atamasco blooms in March-April; Z. candida blooms in late summer. At least that's what they do here in Maryland. The flowers of Z. atamasco are typically much bigger than those of Z. candida, too. Jim McKenney Montgomery County, Maryland, USA, USDA zone 7, where I'm busy trying to photograph as much of the colchicum collection as possible.