Surely the way you measure an attribute depends on what you are going to use the measurements for, ultimately that's a question of precision. If there is a possibility that there will be a variety of uses (reuse) for the data, then an indictation of the degree of precision of the measurement would be highly desirable.

Source and precision stuff is surely important, but it is quite possible to end up with major bloat and more meta than meaningful data. This may not be a problem but there is certainly a practical limit as to how far we can or should go in this direction.

Isn't it also important to distinguish whether the description refers to an actual leaf (ie. that leaf there, on that specimen is ovate) or whether you are making a generalisation about a taxon (ie leaves ovate to obovate)?

Most certainly. I must admit I thought we were talking about taxon descriptive data, but therie is probalby no reason at all why the same principles and data structure/definitions can not be used forthe structures/features themselves.

A taxon cannot have a leaf shape, only leaves can, and an actual leaf does

not

usually vary in shape except through time.

Conversely, only a taxon can have, or not have, ovate leaves. Is this a generalization or a fact? (and does it matter?)

<my_taxon_description> <specimen> <leaf shape="ovate" length_mm="10"/> <leaf shape="ovate" length_mm="8"/> <leaf shape="obovate" length_mm="25"/> </specimen> <specimen> <leaf shape="ovate" length_mm="5"/> <leaf shape="obovate" length_mm="31"/> </specimen> </my_taxon_description>

Conceptually I like this reperesentation - it is what we all do and may or may not write down. But as you say, maybe people want to know this, maybe they don't...

jim

__________________________________________________________________________ Jim Croft ~ jrc@anbg.gov.au ~ http://www.anbg.gov.au/people/croft.jim.html ph 02-6246-5500 ~ fx 02-6246-5248 ~ GPO Box 1600 Canberra ACT 2601