The numbers of characters in interactive keys. Two case studies Rogier de Kok 2006

Ideas about numbers of characters Watson & Dallwitz The Families of Flowering Plants . As many characters as possible Bruce Maslin Key to the Australian Acacia Keep number of characters to a minimum

Watson & Dallwitz

The Families of Flowering Plants .

As many characters as possible

Bruce Maslin

Key to the Australian Acacia

Keep number of characters to a minimum

Many collaborators from all over Australia 1436 taxa 59 characters including distribution characters

Many collaborators from all over Australia

1436 taxa

59 characters

including distribution characters

Families of the Flora Malesiana area Families of Thailand & Indo-China Collaborators mainly from Kew & Leiden 344 taxa 64 characters

Families of the Flora Malesiana area

Families of Thailand & Indo-China

Collaborators mainly from Kew & Leiden

344 taxa

64 characters

Case studies Pea Key Morphology very similar Very few characters are inappropriate for parts of the matrix Species are a small target Few combinations of characters Family key Morphology not very similar Very few characters are inappropriate for parts of the matrix Families are a big target Many combinations of characters

Pea Key

Morphology very similar

Very few characters are inappropriate for parts of the matrix

Species are a small target

Few combinations of characters

Family key

Morphology not very similar

Very few characters are inappropriate for parts of the matrix

Families are a big target

Many combinations of characters

How many characters ? Number of characters in a data set mainly determine the length of the coding time Number of taxa in a data set is much less important in determining the length of the coding time Relationship between the morphological characters space and the theoretical possible number of characters combinations.

Number of characters in a data set mainly determine the length of the coding time

Number of taxa in a data set is much less important in determining the length of the coding time

Relationship between the morphological characters space and the theoretical possible number of characters combinations.

Hypothetical relationship between number of characters and possible combinations (blue) Hypothetical relationship between number of characters and possible combinations in real life (purple)

Making interactive keys Interactive keys are not very good a keying out taxa, but are very good at excluding possibilities Make target as small as possible Use other identification tools in combination with interactive keys

Interactive keys are not very good a keying out taxa, but are very good at excluding possibilities

Make target as small as possible

Use other identification tools in combination with interactive keys