Taxonomic rules for varietal names?
 

I know the rules for orchid species & hybrids, but I am not sure whether any rules apply to varietal names?

Phalaenopsis violacea, variety sumatrana (or Sumatrana?)

Being a species, both names are in italics, with the species name all lower case.

• Should varietal name be in italics or not?
• Should varietal name be capitalized (ever, or only if it refers to a geographical name)?

Good questions... would love to see definitive answers because one sees all sorts of variations on the theme. Another I would like to add to the list of questions... when does one correctly use "variety" (var.) and when is "forma" (fma. or f.) more appropriate. My understanding is that forma is the better term for color forms (eg. alba, coerulea, flava, etc) but then, are there situations where the color forms are significant, geographically or otherwise, where Var. might be preferred?

My understanding is that color forms should be 'forma'. The problem is, that many color forms were published as varieties long before the current understanding took hold.

That's what I thought... not changing tags, trying to use the correct terminology when writing about plant or for display.

Kim, my understanding is that when it comes to species, everything is italicized and lower case except cultivars.

Phalaenopsis violacea v. sumatrana 'The Best'

Rules for validly published varieties and forms are part of International Code of Nomenclature for algae, fungi, and plants, just as for genera and species. For a validly published variety the proper format would be Phalaenospsis violacea var. sumatrana with everything italic except var. If this combination has been validly published it is more recent than any of the usual websites can verify. If it has not been validly published then that format should not be used and an informal notation like Phalaenopsis violacea (from Sumatra) would be preferable.

Form (forma, f.) should be used for minor variations within a population - like the few white flowered plants among the usual pinks, often where both white and pink flowered forms are normal variation you might find among sibling plants. Variety (varietas, var.) should be a regional variant, a distinct population, with one or more distinct characteristics across all or most of the population. There may be cases that could be viewed either way.

Use of var. and f. have changed over time. Which is currently correct in any particular case depends on which was most recently validly published and generally accepted. They often get corrected to current standard when a review or revision of a group is published, but unless the correction has been formally published the original stands.

@ PaphMadMan,

That is clear and concise, but it also reveals that there is no easy way to decide whether a varietal name is valid, and whether it should be written one way or the other.

I tried to look up Paphiopedilum insigne in Orchids Plus, since this species is reported to have more than 100 varieties.

Under species name, I got a listing of 72 publications, but no indication of what varities (if any) are mentioned in each.

When I tried to add some known varieties (sanderae & sanderianum), I got no results. When I tried to add a clonal name (Harefield Hall), I got no results.

When I went back to the Awards search function, I got results for Harefield Hall, but not for the varietal names, unless spelled exactly as entered into the data base. Some are v., others var. and still others hort. var.

The word "variety" for plants is used differently by taxonomists and growers. Growers use it for "anything different that can sell" and tend not to have firm rules for naming varieties.

Many individual nurseries will give varietal names to stock they have propagated for years. As an example, a now-closed family-owned nursery near me for years sold rooted cuttings of the fig Conadria, taken from the large plant in the front yard of the owner, who lived next door. This is a green fig that does very well in high heat. I bought one from Mr. Baker himself in 1986. He declined in mental ability, and his daughters ran the nursery. One day I was there and I saw plants of "Baker fig" being sold. I asked what that was. An employee told me they were cuttings from THAT tree over there, and they'd forgotten the real name. I knew what it was, and told them Mr. Baker had told me that over 30 years ago, but they didn't believe me. So now there are Conadria figs being grown in Phoenix, there are Baker figs being grown in Phoenix, and many people claim to be able to tell the difference.

A lot of plants from the very same population and very same locality, but differing in minor characteristics, like flower color or petal splash, were given different varietal names in the past. Taxonomists mostly ignore these nowadays. To a taxonomist normal population variation is no reason for separation into different taxa. They seem not to be using "variety" any longer. Previous valid publications of a variety would still be valid, but you would have to compare your plant to the original description to see whether it matches the description.

As an example, Engelmann named Peniocereus greggii for a cactus from Texas into Mexico, and Peniocereus greggii variety transmontanus for the plants growing in Arizona and Sonora. I don't know how many pressed specimens of each he examined. The separation was based on minor differences in petal length. The plants are so variable this difference is within the normal variation of any population. If somebody gave you a Peniocereus greggii flower you would never be able to tell whether it is greggii v greggii or greggii v transmontanus unless you measured the petals. People nowadays only put on the variety name if they know were the plant originated, which is seldom, since almost all sold are grown from seed produced from plants in cultivation. And I might point out our Arizona var. transmontanus, grown in cultivation, winds up having petals the length of var. greggii from Texas.

A wild population of a species that is not in breeding contact with the rest of the wild species individuals, and has somewhat different characteristics, might be called a subspecies. But many taxonomists will say the difference needs to be substantial to merit even this.

There is no doubt that the majority of 'varieties' are grower assigned names, which should have been clonal names.

On the other hand, there are some valid and recognized varieties; a couple of good examples are:

Vanda tricolor (white with yellow and brown overlay and pink lip), vs variety suavis (white with maroon spots & pink lip).

Vanda lamellata (yellow/green with a few splashes of light brown), vs variety boxallii (creamy white with clearly defined brown markings)

For flavums, albas & semi-albas, forma should be used.

When writing a scientific paper, due research is required. When writing a newsletter (currently my job), that level of research goes beyond the ability & time available for the newsletter editor.

A source like: Home — The Plant List or https://wcsp.science.kew.org/ will let you enter a genus and species like Paphiopedilum insigne, and bring up a list that includes essentially all of the validly published varieties and forms except the very recent, with publication details available if you click each link. They are listed as synonyms, but that doesn't mean they aren't accepted, just confirms that they are considered to be that species. You can see by publication date which are more recent, but it says nothing about how accepted each publication was. They are good examples of correct format and spelling though.