Since carbonized seed species differ in buoyancy characteristics, and since certain conditions may cause carbonized seeds to become nonbuoyant, the use of both buoyant and nonbuoyant modern carbonized seed species as a recovery standard is suggested in order to provide a more representative measure of flotation device effectiveness. Recovery standards utilizing modern carbonized seeds should be viewed as probable, rather than absolute, determinations of flotation device recovery efficiency because the effectiveness of flotation systems can be significantly altered by subtle changes in technique.