EVOLUTIONARY TRENDS AND CLADISTIC MULTISTATE CHARACTERS

The concept of evolutionary trends is contrasted to the cladistic treatment of multistate characters. It is shown that relatively simple levels of variation demand exploration relative to any resulting classification. This is illustrated by Erdtman's mistaken taxonomic conclusions, which subdivided Labiatae into two subfamilies using pollen variation. An example is provided from Acanthaceae pollen, illustrating that outgroup comparison and character congruence can reduce the number of possible taxonomic conclusions for a multistate character from nine to one.