Single-access Key - Presentation Styles

Presentation Styles

Single-access keys may be presented in different styles. The two most frequently encountered styles are the

• Nested style in which all couplets immediately follow their lead, at the expense of separating the leads within a couplet.
  • The most frequent subtype of nested keys are called "indented key", where indentation increases with each level. With a large key this can lead to much whitespace in print, and consequently little remaining room for lead text and illustrations. Although "indented key" is sometimes used as a synonym for nested key, the indentation itself is not an essential feature of a nested key. (Examples of non-hyperlinked, indented nested keys may be found at www.env.gov.bc.ca)

• Linked style: The leads within a couplet immediately follow each other, making polytomous keys easy to achieve. At the end of each lead some form of pointer (a numbering system, hyperlinks, etc.) create the connection to the couplets that follow this lead.

The nested style gives an excellent overview over the structure of the key. With a short key and moderate indentation it can be easy to follow and even backtrace an erroneous identification path. The nested style is problematic with polytomous keys, where each key must be scanned to the end to verify that no further leads exist within a couplet. It also does not easily support reticulation (which requires a link method similar to the one used in the linked style).