Your excellent photos of blooms are of S. trifaciata 'Laurentii', the yellow edged variety. Yes, it is true many varieties revert to species rather than type, when doing leaf cuttings. Many varieties will revert when done this way. The best part is finding true-to-form varieties that reproduce consistantly. A fine resource for reading is "The Sansevieria Trifasciata Varieties, a presentation of all cultivated varieties" by Juan Chahinian.

This will give you a good basis for which varieties breed true, and remain stable. Which are sports and show up occasionally, and which are truely non-reliable.

Good luck in your search. We have several remarkable growers here who own more varieties than I have ever hoped to have heard of. Please see BirdsNestSoups first posts on the photo gallery to see a True Collection of Sansevieria.

For those who want the yellow border to remain when propagating, always stick with an offset with a piece of the underground stem and root attached. Beautiful specimen!