It is definitely Neomarica, not Dietes grandiflora. The two are not synonymous. As someone pointed out in the other thread, Neomarica is South American, Dietes South African.
Neomarica, the walking Iris, bends the flower stalks (which, incidentally, look similar to the leaves) back to soil level, and roots, forming new plants (hence the name 'walking'). Dietes does not do that.
For what it's worth.