Hello JB. Some of my tall sans from years ago. Had them well over 40 years and never got more than 4 ft. I think the ones Gene mentions are some of the other spices. Your first picture looks like Sansevieria trifasciata Laurentii with the yellow marigins. The next is Sansevieria trifasciata with out the yellow marigins. The next two is Sansevieria trifasciata 'hahnii Siebert'. Notice the faint yellow striping in the center leaf. Which differs from plain hahnii. I love the trifasciata which I have very many. The futuras grow only about 12 to 15 inches tall and many leaves which is wider. Pictures below.
First my regular hahnii;
Second my Hahnii Siebert;
My most loved hahnii Lucille Polen (form of Golden Hahnii) with two pups, one all yellow;
Some of my Futuras;
This one is 'Moonshine' with green molting which I love. I also have the all silver ones.
Got several tall varieties as well.
