ICBN nomenclature of Hieracium

[John McNeill]

Dear Dr Tyler:

I have not checked the extent to which the name Hieracium caesium is in use, but it would appear from what you write ("more commonly it has been used in a wide sense including both 'taxon X' and other more or less similar micro-species) that there may be a fairly wide literature using the name -- despite its application in an apomictic group.

Assuming this and the following facts:

1) the name is currently in use in different countries in different senses;

2) the only known specimen that seems likely to be part of the original material is hard to identify, but is certainly not referable to the taxon to which the name is applied is Sweden -- ? and anywhere else?

then, the most obvious option would seem to be to propose that H. vulgatum var. caesium be rejected under Art. 56.1.

In addition to the information provided in the posting, the formal proposal would require information on current usage, world-wide, of H. caesium, and the nomenclatural implications of the name no longer being available for use for any taxon.  (Cf. Guidelines in Taxon 50: 339-342. 2001 -- also at http://www.botanik.univie.ac.at/iapt/taxon/...  )

As Sennikov has noted, the fact that H. caesium is currently in use in different senses in different countries is the main reason why a conservation proposal would be unlikely to be successful.  But, provided you can demonstrate that "disadvantageous nomenclatural change" would arise unless the name is rejected, then the rejection route is a possibility.

To maximise the chances of success, a joint proposal with other users of the name, certainly Sennikov, but also, perhaps, someone from a country in which the name is used in the different sense to which you refer, would be a good strategy. 

[You could, of course, do as others have suggested and argue that the specimen in the Thunberg collection is not original material, and, if Sennikov does not beat you to it -- under Art. 9.8, a Sennikov lectotypification would, at worst, have priority as a neotypification --, select another specimen that fits current Swedish usage as a neotype.  But then the current situation of the name being used in one sense in Sweden and another elsewhere persists.]

Hope this helps.

John McNeill
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John McNeill, Director Emeritus, Royal Ontario Museum;
    Honorary Associate ,Royal Botanic Garden, Edinburgh
Mailing address:  Royal Botanic Garden, Edinburgh, EH3 5LR, Scotland, U.K.
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