Ruderalis is another strain porkchop, but really rare and im not really sure why it isnt as promonent as the other two,but krush is just a strain.and the other i've never heard of,but if he's heard them they must be out there.btw strain means one of the named plant with specific genetics(i.e white rhino,white russian,purple haze) indica stavita and Ruderalis are familys that the certain strains are grouped in based on genetics