FW: L. or L. emend. Thellung? And the citation of authorities

[Mary Barkworth]

A question came up on GrainGenes about the authorities for Triticum. In
the course of my answer (which was basically the statement in the preface
to the new botanical code there is frequently no point in citing
authorities), I made a comment about the necessity of explaining how the
material used was identified and of making voucher specimens. David
Matthews questioned, quite reasonably, my statement about voucher
specimens. His question - and my reply -follows. If others wish to comment
- the addresses for the two groups involved are
grains at greengenes.cit.cornell.edu and graintax at greengenes.cit.cornell.edu
________________________________________
Dave Matthews raised a good point:


You mean for every paper that's been published on Chinese Spring there
should be a herbarium specimen deposited, to verify that it's T. aestivum?
Doesn't seem feasible, or useful.  If not, what situations do justify
archiving a voucher specimen?
_______________________________________
My reply:

I agree, depositing a voucher for each paper on Chinese Spring would be
rather absurd. Besides, can one tell a Chinese Spring cultivar purely on
the basis of morphology?

When are vouchers really needed?

The kind of paper that comes to mind are those about species for which the
original accession was collected from native populations, particularly
species whose taxonomy is controversial or whose identification is
difficult.  But if there are a series of papers from the same institution
all based on the same accession, the same specimen can serve as the
voucher for all of them - but its location should be cited in the paper.
Why make different specimens for work at different institutions? Because
identifications should be checked at the start of any series of studies.
There are errors and, despite the best efforts of those responsible, I
suspect they can be introduced.  The other reason is that I think it
important to be aware of the organism with which one is working - as an
organism.

As a taxonomist, I firmly believe that a voucher specimen should be made
at the time seed is collected, even though it is time consuming. Then
after the seed is first grown out. This is particularly important if the
original collections were made where two or three species were growing
together. If the accession is then subjected to selection and eventually
released as a cultivar, there should be a voucher specimen made of the
cultivar - which should be accompanied by whatever is required to
establish the cultivar as distinct.

Do genebanks routinely make herbarium specimens for all their accessions?
This would be helpful, but I would still recommend making a voucher
specimen for the first of a series of studies undertaken at some other
institution, checking its identity, and then depositing it in a nearby
herbarium that is listed in index Herbariorium as willing to make loans.

I should state my bias here. I am a taxonomist who is preparing an account
of the grasses of North America. I am told that several species have been
made available as forage and restoration species, but if I inquire about
specimens either to check identifications or prepare descriptions, all too
often it appears that none have been made. Yes, it takes time to make
herbarium specimens - but they do ensure that others can verify the
accuracy of the identifications or, if there is a taxonomic change such as
realization that what has been considered one species really is 2-3
different species, then the results of a paper can be re-evaluated.
Without the voucher specimen, all one knows is that one of the species has
the properties described - or that, on average, the group of species have
them.

I hope that this provides more realistic guidelines. I am also posting it
to a taxonomists listserver.