# Some thoughts about nomenclature



## Error (Apr 16, 2004)

Beware: I am about to idly nitpick something that probably functions just fine as-is.

I have been thinking recently about the way we (planted aquarists) name and catalog our plants. The current method is much as follows:

_Genus species_ var. _variety_ 'Cultivar/color/location/miscellaneous descriptor'

The first three items (genus species variety) are fine. The cultivar/color/location/etc., however, I find muddled and misused. Perhaps some examples would help me explain what I mean:

_Ludwigia inclinata_ var. _verticillata_ 'Pantanal'
and
_Rotala mexicana_ 'Araguaia'

should _really_ be

_Ludwigia inclinata_ var. _verticillata_ from Pantanal
and
_Rotala mexicana_ from Araguaia

'Pantanal' and 'Araguaia' are the regions where these plants are from, not the name of a man-made cultivar or color, and shouldn't follow the Latin in single quotes. Alternatively, the following are correct:

_Rotala_ 'Colorata'
_Hygrophila polysperma_ 'Sunset'
and
_Cryptocoryne cordata_ 'Rosanervig'

...because they are ACTUAL cultivars and thus should have their cultivar names in single quotes after their genus and species epithets.

I guess what I'm getting at here is that a plant's collection location shouldn't become its cultivar name. And stuff like:

_Rotala macranda_ 'Green Narrow Leaf'

if NOT man-made, feels better to me as:

_Rotala macranda_ (Green Narrow Leaf)

I'm just thinking aloud and hoping to spark a discussion here, so don't take me too seriously. Feel free to add your thoughts. Accuracy is important, but no information is really lost as a result of the system we have already. But perhaps it could be better...particularly for a detail-oriented person like myself.


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## Jeffww (May 25, 2010)

I think it's because single species can show a very wide range of variation between regions. Rotala mexicana "of" Goias looks a lot different from Rotala mexicana "of" araguia. Thus you can call them "varieties".


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## Michael (Jul 20, 2010)

Jeffww said:


> I think it's because single species can show a very wide range of variation between regions. Rotala mexicana "of" Goias looks a lot different from Rotala mexicana "of" araguia. Thus you can call them "varieties".


A regional or geographic variation is indeed a "variety", sometimes called a race or subspecies. This corresponds to the third word (trinomial) in a scientific name. But a variety is NOT a cultivar. Cultivars are variations which occur in horticulture, not nature, and are designated with single quotation marks and a normal typeface, not italics.

I think Error's point is that we confuse variety, subspecies, cultivar, and geographic origin, and that we should be more careful and precise.


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## Cavan Allen (Jul 22, 2004)

Error said:


> _Ludwigia inclinata_ var. _verticillata_ 'Pantanal'
> and
> _Rotala mexicana_ 'Araguaia'
> 
> ...


I think that's correct, really. That does indeed differentiate naturally-occurring plants from real cultivars. But the 'colorata' is not a cultivar, as far as I can tell. It's probably naturally occurring but lacks any really useful location data in the trade name. What of plants like that? Obviously, names like that are placeholders until a species name can be pinned down, but it's all we have for now. If we only had names like 'Araguaia' with which to contend, it would be a simpler matter. If a simple means of distinguishing those could be found, I'd be all for it. The parenthesis don't really work for me.


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## Cavan Allen (Jul 22, 2004)

Michael said:


> A regional or geographic variation is indeed a "variety", sometimes called a race or subspecies.


In botanical terms, subspecies is stronger - or outranks - variety. A subspecies is more like a weak species. People often use variety loosely to describe cultivars and so on, but it's really not the same as when it's used botanically.


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## Michael (Jul 20, 2010)

Cavan Allen said:


> In botanical terms, subspecies is stronger - or outranks - variety. A subspecies is more like a weak species. People often use variety loosely to describe cultivars and so on, but it's really not the same as when it's used botanically.


Agreed.


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## Error (Apr 16, 2004)

Cavan Allen said:


> Obviously, names like that are placeholders until a species name can be pinned down, but it's all we have for now.


This is true. But the examples I gave for Lud. Pantanal and Rotala Araguaia are pretty concrete. Much of that can be nixed wholesale if we are serious about it.

But that's the problem--the system (whether 'correct' or not) seems to function just fine and adequately distinguishes one plant from another. Why change it?

In theory, plants 100 feet apart could be different genetically even though we'd still say they were the same 'species'.

Lots of arbitrary lines drawn in taxonomy.


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