Species names are internationally recognised and follow rules first described by Linnaeus and updated continually ever since 1753. The "International Code of Botanical Nomenclature" applies to the naming of species. Species are recorded by the International Plant Names Index and by the International Organisation for Plant Information while China has done work on their species. These all differ! The American Rose Society is responsible to the World Federation of Rose Societies for the registration of rose cultivar names only.

Species names at first glance appear simple. This is not so. Every species has a certain amount of variability as in any human family. This has meant that some species have been described by a number of people. One species had been described twice with different names by the same person! Experts are still arguing about which is the earliest written description for some species and therefore the correct name. The incorrect names are referred to as synonyms. There is also the case where a name is very well established, incorrect and miss-spelled. This is Rosa luciae which is well-known as R. wichuraiana and now corrected to R. wichurana. The solution for this rose is to use R. luciae as the botanic name and R. wichurana in the horticultural world.

Roses also interbreed very easily which makes species distinction difficult. In the wild some species are distinct because they flower at different times and therefore cannot cross pollinate. Sub-species are referred to as varieties or var., have less variation than the species and are written R. species var. name. Named selections are written as R. species 'Name' and are always cloned. Species crosses are usually written as Rosa species1 x Rosa species2. Either the species are listed alphabetically, or, where the female parent is known this is listed first. These two conventions can cause confusion as it is not often clear which convention an author used. These species crosses are a little awkward as there is no agreement as to how a species cross should be handled unlike genera crosses where a new name is created by combining parts of both genera names. I am not sure how the Rosa x Hulthemia are being handled as the only references that I have seen treated them as if they were named rose hybrids. Some species crosses have been given names as if they were typical hybrid roses i.e. 'Cantabrigiensis' which is known to be a species cross found in the Cambridge Botanic Garden

In this article Rosa and R. have been used interchangeably but Rosa should be used to avoid miss-understanding when other plants are mentioned and roses are not the prime subject.