The leaf cuticular waxes of six Salix clones (one Salix miyabeana, one Salix dasyclados, one Salix eriocephala, two Salix purpurea, and one interspecific hybrid of Salix eriocephala x interior) with different biomass productivities were characterized by gas chromatography-mass spectrometry. Total wax content ranged from 6.3 to 16.8 microg cm(-2), and two distinct patterns of wax were measured. The wax from leaves of S. dasyclados 'SV1' differed from all other clones and was dominated by fatty acids (42%), high concentrations of n-alkanes (25%) and n-alcohols (28%), with low n-aldehyde content (4%). All other clones produced cuticular wax dominated by n-alcohols (32-51%), particularly 1-hexacosanol, with fatty acids (14-37%) and n-aldehydes (19-26%) present in lower abundances. Clones of Salix grown under identical environmental conditions produce noticeably different amounts of cuticular wax. In contrast to previous studies of Salix, total wax content was independent of biomass productivity, measured as basal area, suggesting that wax production is not directly linked with woody biomass production by shrub willows under these site conditions.