I disagree with Murray Fletcher's view that any couplet having "not as above" is a poor couplet. Some (many, most?) taxa are polythetic entities or are especially variable in individual characters - a simple way to isolate them in a key (rather than following them through all possible leads) is to specify the combination of characters that allows identification. As long as no other taxon in the key has that precise combination of features, then the couplet works, and that's one key to a good key.

Richard J. Jensen | E-MAIL: rjensen at saintmarys.edu Dept. of Biology | TELEPHONE: 219-284-4674 Saint Mary's College | FAX: 219-284-4716 Notre Dame, IN 46556 |