Herbarium
About nomenclatural standards
The identification of cultivated plants needs a different approach to that required for wild plants. There are usually floras and monographs for wild species and a herbarium specimen can nearly always be found somewhere. For the horticultural taxonomist however, the plant in question could have originated in any country so finding the right flora is a often matter of experience and instinct. However the plant may have been selected simply because it was different to all the others growing in the area in size, colour or habit and the difficulties are compounded by deliberate or accidental hybridization.
The type system is established for species so a comparable system is needed for cultivated plants. The nomenclatural standard for a cultivar is the designated herbarium specimen, or illustration if more appropriate, showing the characters which distinguish that plant from others in cultivation.
The value of a nomenclatural standard is increased considerably if it is augmented with additional information about the plant, such as detailed descriptions, colour references, origin or parentage, original publications and any other material which confirms the identity of that plant. It is also useful if the whereabouts of the living plant from which the nomenclatural standard was prepared, is noted together with dates. All this information constitutes the Standard Portfolio for the plant and is in accordance with Principle 3 of the International Code of Nomenclature for Cultivated Plants 1995 which states:
"The selection, preservation and publication of designations of nomenclatural standards is important in stabilizing the application of cultivar and group names. Particular cultivar names are attached to nomenclatural standards to make clear the precise application of the name and to help avoid duplication of such names. Although not a requirement for the establishment of a name, the designation of such standards is strongly to be encouraged."
Nomenclatural standards and the Royal Horticultural Society's Herbarium
In 1999, an assessment of specimens, photographs and paintings in the RHS Herbarium was initiated, to identify possible nomenclatural standard specimens.
Decisions, sometimes difficult, had to be made as to whether each specimen and illustration could be designated retrospectively as a nomenclatural standard. RHS records, international registers and monographs were studied and whenever possible, in cases of doubt, exhibitors or raisers were contacted. Having determined that a specimen or illustration could validly be designated a nomenclatural standard, it was filed and the details entered onto the RHS Horticultural Database. Additional facts, illustrations, useful references were also recorded. The results may be found by searching the RHS Standards database.
It is now proposed to encourage raisers of new cultivars to provide photographs and fresh material from which descriptions and herbarium specimens may be prepared. These will be stored in the RHS Herbarium, and by searching from this site, it will be possible to determine where the herbarium material and records may be consulted.
Other institutions maintain herbarium collections, some of which contain nomenclatural standards and the future aim is to create links so that the search for nomenclatural standard may be widened. Details of nomenclatural standards from one or two other institutions are already available on this website.
Why are nomenclatural standards important?
To name a new cultivar (a cultivated variety), a brief catalogue description is all that is required. This may be as simple as "flowers blue" which is not helpful. There are thousands of shades of blue and everyone has a different idea of how sky blue differs from powder blue. A more helpful catalogue may state that the plant is taller than 'Susan's Surprise' (an older well-known plant) but what happens if 'Susan's Surprise' is no longer in cultivation? Even if it is still to be found in gardens, how can one be sure that the existing plant of that name has not sported or is not a somewhat similar seedling?
These are questions frequently asked by gardeners and nurserymen. Is a newly discovered plant really new or simply a rediscovery of an existing plant thought to be lost? It is easy to understand why plants come to have several different names and how confusion can arise.
This problem has been addressed for some groups of plants by individual specialist societies producing checklists and the relevant International Registration Authorities who publish cultivar registers. However, for many plants it takes much research to find a suitable description of a cultivar and often the results are inconclusive.
If herbarium specimens, photographs and detailed descriptions of all newly raised or introduced cultivars are deposited in a herbarium, accessible to all, the problems for future gardeners, nurserymen and botanists will be eased.
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