Hardyana gx is also a C. Hardyana gx. However, the hybrid produced between Cattleya Hardyana gx and C. dowiana is not C. Hardyana gx, but C. Prince John gx. In summary: C. Hardyana gx = C. warscewiczii × C. dowiana C. Eleanor gx = C. Hardyana gx × C. warscewiczii C. Prince John gx = C. dowiana × C. Hardyana gx Registration of greges When the name of a grex is first established, a description is required that specifies two particular parents, where each parent is specified either as a species (or nothospecies) or as a grex. The grex name then applies to all hybrids between those two parents. There is a permitted exception if the full name of one of the parents is known but the other is known only to genus level or nothogenus level. New grex names are now established by the Royal Horticultural Society, which receives applications from orchid hybridizers. Relationship with nothospecies The concept of grex and nothospecies are similar, but not equivalent. While greges are only used within the orchid family, nothospecies are used for any plant (including orchids). Furthermore, a grex and nothospecies differ in that a grex and a nothospecies can have the same parentage, but are not equivalent because the nothospecies includes back-crosses and the grex does not. They can even have the same epithet, distinguished by typography (see botanical name for explanation of epithets), although since January 2010 it is not permitted to publish such grex names if the nothospecies name already exists. Hybrids between a grex and a species/nothospecies are named as greges, but this is not permitted if the nothospecies parent has the same parentage as the grex parent. That situation is a back-cross, and the nothospecies name is applied to the progeny. References Bibliography External links "Quarterly Supplement To The International Register And Checklist Of Orchid Hybrids (Sander’s List) January – March 2014 Registrations" Distributed with The Orchid Review 122(1306) (June 2014), The Royal Horticultural Society. Guide lines and rules for composing grex, group and cultivar names. Summary of ICNCP rules and guidelines for Grex and Cultivar epithets. Botanical nomenclature Orchid hybrids