Interactive Identification of New World Salix (Salicaceae) using Intkey

By George W. Argus

The Alaska Natural Heritage Program of the University of Alaska Anchorage is pleased to host this website in affiliation with George W. Argus, Curator Emeritus, Canadian Museum of Nature, Ottawa, Canada.


This site includes files which may be used in the interactive identification of New World Salix (willow). The Intkey program is a part of the DELTA (DEscriptive Language for TAxonomy) system invented by Michael Dallwitz in 1980 (Dallwitz, M. J. 1980. User’s Guide to the DELTA System: a general system for encoding descriptions. CSIRO Division of Entomology, Canberra, Australia).

I have been using the DELTA System for many years to manipulate Salix data in the preparation of floristic treatments (including descriptions, keys, and geography), interactive identification, and numerical taxonomic studies.

In field workshops given in Alaska, Alberta, British Columbia, California, Maine, Ontario, and Oregon I taught willow classification and biology with emphasis on interactive identification.

The purpose of this webpage is to make my Salix database widely available to anyone interested in Salix identification.

The included taxa mainly are native New World species, subspecies and varieties, but some are naturalized species and hybrids.

Each of these taxa can be scored for 232 characters including morphology and biology, geography, classification, administrative and bibliographical data, synonymy, common names, notes, and references.


To use the interactive Salix key, download the following files:

1. Salix (willows) in the New World: Guide to the Interactive Identification of Native and Naturalized New World Salix using Intkey (DELTA). (2.6 MB pdf) (Last updated April 21, 2009). This Adobe pdf file contains instructions on the use of Intkey, lists of taxa and characters, character notes, glossary, and figures illustrating Salix mormphology.

2. Intkey software:

  • DELTA.REG – Information on DELTA registration.
  • DELTA.USE – Information on the limited use of the Intkey software.
  • INTKEY5.EXE – A Windows version of Intkey.
  • INTKEY4.HLP – Intkey Help.
  • TOOLBAR.INP – Toolbar.
  • *.BMP – Toolbar icons.
  • Miscellaneous Program Files

3. Salix (Last updated Febuary 29, 2012). Data Files: Archive

  • ICHARS – Machine language character file.
  • IITEMS – Machine language coded taxon descriptions.
  • INTKEY.INI – Initialization file for the Salix database.

These files are frequently updated. Check this site regularly for the latest version.



Delta System


The author requests that if you use Salix Intkey you send him a brief message to

Please direct questions and comments regarding this page and Intkey to:

George W. Argus
R.R.3-310 Haskins Rd.
Merrickville, Ontario Canada
K0G 1N0 613-269-4605

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