Mary Sue, the name honored Mrs. Katherine Wilson. She and her husband Morris Clint were the first to explore the extraordinary abundance of Zephyranthes in Mexico. Thad Howard "latinized" the name and from Katherine it was katherina and the species, katherinae. So far as I know only the tomato red and the yellow forms remain in cultivation. Fortunately it is one of those species that with its clawed tepals appearance can be quite readily identified. There were many color forms in cultivation and it would not be surprising that someone still has them. And, there are two groups of Rainlilies, one needs late summer rainfall like candida and several Habranthi or Rhodophiala bifida but you also have a lot of others, species and hybrids that demand rainfall (or copious watering) in May in your Hemisphere. They need lots of water to flower, in autumn OR in spring, depending on the part fo the world they come from.