names and numbers

Curtis Clark jcclark at CSUPOMONA.EDU
Sun Oct 21 18:29:52 CDT 2001

At 12:47 PM 10/21/01, Jim Croft wrote:
>The determination assertion (specimen identification) is obviously quite
>a different beast to a taxon assertion (taxon circumscription or
>concept), although the latter can be thought of as the totality of the

I'm just starting to get my head around all this, so I can't vouch that
this will make sense:

A circumscription that is the sum of all the determinations (by a single
individual, of course) is bottom-up, and can only be extended by the
original determiner--If I have a freshly collected California poppy at
hand, there is no way to know if the late W. L. Jepson would have
determined it as Eschscholzia californica.

A circumscription based on a description is top-down: the description can
be applied to specimens that its author never saw. But those applications
each have their own determiner.

The former circumscription would be easy to implement (AFAIK all specimen
databases that record every determination of a specimen could do it), and
more objective. But its lack of extensibility would be a problem, one that
might be solved to some extent by a hierarchy of circumscription ("Jepson
determined it, I believe it, that settles it, and I've made these
additional determinations as well, so mine are a superset of his").

I don't see any clear way to implement the latter type of circumscription.
It's easy enough to record descriptions, but applying them is problematic
in any circumstance, database or otherwise.

Curtis Clark        
Biological Sciences Department             Voice: (909) 869-4062
California State Polytechnic University      FAX: (909) 869-4078
Pomona CA 91768-4032  USA                  jcclark at

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