When is a family not a family?

Recent molecular investigations of the small-subunit rRNA gene sequences have indicated that established taxonomic hierarchies can be clearly at odds with the degree of evolutionary divergence (as inferred from molecular divergence) between supposedly equivalent taxa at every rank (i.e., species through class), both within and across biological divisions. This is particularly true between the Rhodophyta and the Phaeophyta, whose higher-order taxa appear under- and overinflated, respectively. We present two plausible alternatives that algal taxonomists might adopt in order to invoke discussion on their relative merits.