Unfortunately, nurseries do not always correctly identify plants. It may not be their fault -- they use the name supplied by the grower. Most of what is sold as Neomarica gracilis seems to be N. northiana. I have not seen the genuine N. gracilis sold in the U.S. Similarly, Dietes grandiflora is sold variously as D. vegata or D. iridoides. The true D. iridoides is hard to come by. David E. Central Coastal California