OK, I looked up eucallis and sanguineus in the 1984 booklet, "A Review of the Southern African Species of Cyrtanthus" by Reid and Dyer. The flower I have is sanguineus.
Sanguineus: larger flower, petals recurved, single bloom in umbel.
Eucallis: smaller flower, not recurved, up to 6 flowers in the umbel.
So perhaps I now have a second clone of sanguineus and can try to produce seeds of this species in the future. Meanwhile, does anyone know where I can get seeds or a bulb of eucallis?
Jim