Naming of Plants
The naming of plants is a complex issue. Many books are written about it, taxonomists continually revise names as more information come to light, breeders continually develop new varieties, and marketing organisations need names that appeal to consumers.
All living things are placed in a hierarchical classification which tries to group them together by how closely related they are to each other.
For our purposes, we need consider only groupings at the family level down.
Family: groups together related genera (singular genus). Thus the family Scrophulareaceae contains the genera Antirrhinum, Linaria, Mimulus, amongst others.
Genus: groups together related species. The genus Antirrhinum contains the species Antirrhinum majus, Antirhinum glutinosum, many others.
Species: a species is normally defined as a group of plants that will breed with each other but which normally will not cross breed with other groups. There are exceptions to this, with many (particularly vegetatively propagated) varieties being the result of cross breeding that would not take place in nature without some assistance.
Variety: a group of plants with closely defined properties, distinct from other varieties, uniform in their appearance and stable across generations of propagation.
In the case particularly of bedding plants, varieties may also be grouped together in series so that different colours can be grown together with the plants otherwise having similar growth habit and performance.
For our purposes, we will not go beyond these levels in our catalogue, although we do try and group together plants that can be used in combination in various ways, and by how they might be used.
For those interested in understanding the full complexity of horticultural nomenclature, follow this link - http://www.hortax.org.uk/ .