Hints on using the key


A. R. Bean and M. J. Dallwitz


The interactive key uses the program Intkey, which runs under MS Windows. To install the latest version of Intkey, run http://delta-intkey.com/win32/intk32.exe. With a broadband connection, installation takes about 1 minute. The size of the download is about 2MB, and the size of the installed program is also about 2MB.

The program is initially in ‘Normal Mode’, which is suitable for most purposes. To extend the range of options, select ‘Advanced Mode’ from the ‘File’ menu, and read the ‘help’ for the additional toolbar buttons and menu options that then become available.

Worked examples using Intkey for identification and information retrieval are available at http://delta-intkey.com under ‘Overview of the DELTA System’.


At startup, the top-left pane is headed ‘Best Characters’. Your identification will usually be quicker and more accurate if you use characters near the top of this list. However, if you want to see the characters in their ‘natural’ order, click the button.

  1. In the top-left pane, click on a character that you feel confident you can use.
  2. The program displays a list of character states, or a box for entering values such as lengths. If there is an illustration for the character, it will be displayed automatically. Click on the state, or enter the value, that applies to your specimen, and click ‘OK’. If you aren’t sure, don’t guess a single state or value. Instead, click on more than one state, enter a range of values, or click ‘Cancel’ and try another character. To deselect a previously selected state, click on it again.
  3. The ‘Taxa Remaining’ (top-right) pane shows the taxa that match the information that you have entered. The ‘Taxa Eliminated’ (bottom-right) pane shows the taxa that do not match, with the number of mismatches in parentheses. Repeat from step 1 until ‘Identification complete’ or some other message is displayed in the top-left pane. A ‘Help’ button is also displayed; click this to obtain information on how to proceed (for example, how to confirm the identification).

If, at any stage, you think you’ve made a mistake and want to correct it, click on the appropriate character in the ‘Used Characters’ (bottom-left) pane. The program again displays the box for selecting character states or entering values, and you can change the information you previously entered. You can remove the character from the identification by clearing all the information.

Checking identifications

Tentative identifications should be checked against further information. Full descriptions, diagnostic descriptions, and illustrations are available via the (Information) button.

Another way of checking is to increase the error tolerance value and proceed with the identification.

For more information, click the ‘Help’ button that is displayed at the completion of an identification (i.e., when 1 or 0 taxa remain).

Error tolerance

If you think your tentative identification is incorrect, click the button (Set the error tolerance), enter a higher value, and continue the identification.

Geographical distribution

The ‘distribution by state’ and ‘botanical district’ characters allow you to restrict the species under consideration by specifying where your specimen was collected:

If the species was not previously recorded from that area, you can still reach a correct identification by using error tolerance.

You can also specify geographical subsets of the taxa by means of the button (Use a subset of the taxa), but with this method the restriction is not subject to error tolerance. There are subsets defined for Australian states, and for some miscellaneous smaller regions. You can also define subsets yourself from a list of the species occuring in an area. For example:

*DEFINE NAMES "Rockinover River"

Solanum abutiloides

Solanum beaugleholei

Solanum callium

Solanum defensum

You can add the definition to the Intkey initializaton file ‘intkey.ink’, or store it in a separate text file, e.g. ‘rockinover.inp’, and invoke it (in ‘Advanced Mode’) by selecting ‘File > File > Input...> rockinover.inp’.

For convenient access, there are special toolbar buttons to access predefined subsets for the eastern states.


The ‘classification’ character allows you to specify the subgenus or section to which your specimen belongs.

If you are mistaken, you can still reach a correct identification by using error tolerance.