Confusing Moore's horsetail (Equisetum × moorei Newman) with rough horsetail (Equisetum hyemale L.) is a known problem in many countries. In our paper, we review some of the features used for their identification concerning their usability. We examined Equisetum hyemale stands in the Nyírség reported in the literature and E. hyemale specimens of the Herbarium of the University of Debrecen that were collected in the Nyírség. We found that most of these stands and herbarium specimens are actually E. × moorei. The occurrence of E. hyemale was only confirmed in Bátorliget. We also report several new occurrences of Equisetum × moorei in the Nyírség. To better separate the two taxa, we recommend micromorphological examination of the surface of the shoots, which can be performed in the field, as well as observing the height of the leaf-sheath.