Character coding and inapplicable data

inapplicable character states occur when character complexes are absent or reduced in some of the taxa. Several approaches have been proposed for repr esenting such states in a character matrix so that the inapplicable conditi on has no effect on the placement of taxa and/or the applicable states are independent and not redundant. Here we examine each of these approaches and demonstrate that all have shortcomings. Coding inapplicables as "?" (reduc tive coding), although flawed, is currently the best way to analyze data se ts that contain inapplicable character states. (C) 1999 The Willi Hennig So ciety.