Nomenclature rules

[shakkai]

I wanted to know if parentage of a named cross is commutative?

For example, I have a seedling that is labelled Masd. (veitchiana x cucullata) - is this then Bocking Hybrid reg. 1899 (cucullata x veitchiana)?

Also I wondered about varieties of species and how/if that effects names. Another example, I have a seedling Paph. (primulinum x armeniacum var. markii (album)) - is this in fact Gold Dollar (primulinum x armeniacum)?

Thanks very much for clarifications!

[Ray]

The hybrid is considered to be the same no matter which way the cross is made. I'm not sure that should be that way, as mitochondrial DNA in the capsule carrying parent can play a larger role in the outcome. (That's why it's nice to make reciprocal crosses, so you can see the difference.)

Varieties also play no role in the hybrid name, but sometimes a variety is later reclassified as its own species, in which case its hybrids would get their own names.

By the way: The cross is Paph Golddollar (one word), and according to the RHS, it's Paph. armeniacum forma Markii, not variety. (I have absolutely no idea what the difference is.)

[littlefrog]

Yes, for registration purposes it does not matter which is pod and which is pollen. If you remake the cross in the reverse order, the name still holds.

For most practical purposes, a variety or form of a species does not matter for purposes of registration. It may matter a lot for the outcome, but that isn't taken into account. This can make for problems later, if a variety is promoted to species status, for example.

[littlefrog]

Jinx Ray, you owe me a coke... *grin*

[shakkai]

Thanks, Ray and Rob! I suppose things get complicated enough without differentiating pod vs. pollen parents as well!

Ray, you've peaked my interest now, and I am going to go and try to find out what constitutes a <i>forma</i> vs. a variety. Thanks also for the correction on the name Golddollar. I can now safely go and label these with the correct hybrid names!

[shakkai]

I checked the International Code of Botanical Nomenclature
(although the Vienna Code appears not to be online yet, so this is from the St. Louis Code) but this didn't seem to clarify the difference:

CHAPTER I. TAXA AND THEIR RANKS

Article 4

4.1. The secondary ranks of taxa in descending sequence are tribe (tribus) between family and genus, section (sectio) and series (series) between genus and species, and variety (varietas) and form (forma) below species.

So, I found this paper (though I didn't pony up the $12 for the full article - just read the summary!) which states:

"Subspecies and varieties usually defined as requiring some integrity - geographic, ecologic, and/or phylogenetic - beyond the morphological. Despite some attempts to differentiate between subspecies and variety, they are largely equivalent in practice. European taxonomists tend to favor subspecies, whereas their counterparts in the United States usually employ variety. Formae usually are defined as lacking any extramorphological integrity."

-- Current practice in the use of subspecies, variety, and forma in the classification of wild plants, Clement W. Hamilton & Sarah H. Reichard, August 1992


So, it appears that if the range is distinct, or the environment is quite specific - i.e - completely hypothetical - only red flowers in the dry area, only yellow flowers in the wet area - then each is a variety of that species. But if red and yellow are present in the same place, in the same environment, then you have a yellow form and a red form... At least, this is how I interpret it!