A nomenclatural standard is the specimen or image that forms the definitive reference to interpret the name of a cultivar. As the RHS Herbarium specialises in plants of garden value, more especially cultivars, there is an active programme of acquiring standard specimens.
Currently, the RHS Herbarium has nearly 5,000 nomenclatural standards.
What is a nomenclatural standard?
Above is an example of the standard portfolio for Agapanthus 'Angela'. In this example the nomenclature standard takes the form of a herbarium specimen. A description is attached to the specimen, which includes the colour of the floral features using the RHS Colour Chart. Part of the standard portfolio includes a photographic transparency showing the habit, form and colour, details frequently lost in pressing.
The first place of publication is a vital piece of information for interpreting the cultivar. Such a standard portfolio provides a vital resource for botanists and researchers.
Type specimens provide a permanent reference point to determine the correct application of scientific plant names. Under the rules laid out by the International Code of Botanical Nomenclature each name at the rank of species or below must have a type specimen attached to it. The RHS Herbarium also has a number of type specimens.