Graham Rice
Sun, 08 Apr 2007 04:22:54 PDT
Well summarised, John. Excellent. If only nurseriesd wouldn't say 
things like: "We don't like groups, so we just call them all 
cultivars instead."

The full notes on plants names from the RHS PlantFinder can be found here:

Meanwhile, back in the garden...

22F and a little overnight snow here in PA, my various A. italicum 
forms which had started to produce new leaves in 60F a week or two 
back are flat on the ground and frozen solid. Not good.

Graham Rice

>Quite a few mesages have flown through cyberspace since this question was
>asked, but it needs an answer.
>Are you using your "horticultural group system" like a grex in the
>>  orchid world?
>>  What would the naming convention be if we were to follow this suggestion?
>>  Carlo
>It's probably easiest to copy out the notes in the RHS Plant Finder that
>define a group and a grex:
>Within orchids, hybrids of the same parentage, regardless of how alike they
>are, are given a grex name. Individuals can be selected, given cultivar
>names and propagated vegetatively. For example Pleione Versailles gx
>'Bucklebury', where Versailles is the grex name and 'Bucklebury' a selected
>     This is a collective name for a group of cultivars within a genus with
>similar characteristics. The word Group is always included and, where cited
>with a cultivar name, it is enclosed in brackets, for example Actaea simplex
>(Atropurpurea Group) 'Brunette', where 'Brunette' is a distinct cultivar in
>a group of purple-leaved cultivars.
>     Another example of a Group is Rhododendron polycladum Scintillans Group.
>In this case R. scintillans was a species that is now botanically 'sunk'
>within R. polycladum, but it is still recognised horticulturally as a Group.
>     Group names are also used for swarms of hybrids with the same parentage,
>for example Rhododendron Polar Bear Group. these were formerly treated as
>grex names, a term now used only for orchids. A single clone from the Group
>may be given the same cultivar name, for example, Rhododendron 'Polar Bear'.
>In the case of Arum italicum with strongly white-veined leaves, which have
>been variously known as 'Marmoratum' (= marbled) or 'Pictum' (= painted),
>there is clearly a vast number of seedlings that bear this characteristic.
>They can't all be one cultivar, but they certainly share the defining
>character of white veins and as such the Group concept is ideal. Since
>'Pictum' is an undesirable name because of the existence of the species Arum
>pictum, Marmoratum is the preferred epithet and Marmoratum Group would
>therefore be most appropriate. Within the Arum italicum Marmoratum Group are
>numerous selected cultivars (some of dubious value, mind you!) e.g. 'Winter
>Beauty', 'White Winter' and these would be written Arum italicum (Marmoratum
>Group) 'White Winter'. Seedlings from the clone 'White Winter' would then
>just blend back into the Group, unless one were sufficiently distinct to
>warrant a cultivar name.
>My reservation about the Group concept is that in (let's call them)
>unparticular hands it could be used to make something seem better than it
>is, and can conceal a multitude of inferior plants. For example, the Actaea
>(formerly Cimicifuga) 'Brunette' example, the seedlings can be only just
>brown over green, but still count as Atropurpurea Group. The wise gardener
>will always go for a named selection anyway, but the less experienced might
>be seduced into getting something inferior that bears an important-sounding
>name - 'full of sound and fury, signifying nothing.'
>As always, careful definition of the Group, or cultivar's characteristics is
>very important.
>John Grimshaw
>Dr John M. Grimshaw
>Sycamore Cottage
>Nr Cheltenham
>Gloucestershire GL53 9NP
>Tel. 01242 870567
>Easter Monday 9 April, Arboretum Weekend 15-16 September
>Gates open 1pm, last entry 4 pm
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