nomenclature precedence

[Una Smith]

Colin Smith wrote:

>In a recent paper author X states that author Y (published in 1821)
>failed to give a clear definition of a taxon (plant).  Author X
>therefore re-names this taxon
[...]

What is a "clear definition"?  If author Y gave *any* description,
then the 1821 name would seem to be valid.

        Una Smith               una.smith at yale.edu

        Department of Ecology and Evolutionary Biology
        Yale University
        New Haven, CT  06520-8106