The International Code of Nomenclature for Cultivated Plants (ICNCP) regulates the naming of cultivars, cultivar Groups and graft-chimaeras. Examples are
Ä Clematis alpina 'Ruby' : a cultivar within a species
Ä Magnolia 'Elizabeth' : a hybrid between at least two species
Ä Rhododendron boothii Mishmiense Group: a Group name
Ä Crataegomespilus : a graft-chimaera of Crataegus and Mespilus.

Note that the ICNCP does not regulate trademarks for plants: trademarks are regulated by the law of the land involved. Nor does the ICNCP regulate the naming of plant varieties.

Orchids have a Code of their own that operates within the limits set by the ICNCP.