This interactive Salix key was developed by Dr. George W. Argus [Curator Emeritus, Canadian Museum of Nature, Ottawa, Canada]. It includes primarily native New World species, subspecies and varieties, but some naturalized species and hybrids are also included. There are 232 characters available to score and identify a Salix taxon. The key is very useful as it enables identification of willow species based on plant material even when catkins are not available.
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).
Dr. Argus has 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.
To use the interactive Salix key, download the following files:
These files are frequently updated. Check this site regularly for the latest version.