Worldwide there are 400-450 willow species, of which 90 are indigenous in Europe. In Finland there are, as currently understood, 20 species, 6 subspecies and 2 varieties, totalling 28 taxa. In addition, 47 hybrids, including 6 intermediate taxa within species, are listed. Very rare ones, triple hybrids and dubious records are excluded. Diversity is the highest in the northern boreal zone with 19 taxa, next is the middle boreal zone with 16. In the oroarctic belt there are 11 taxa, and in both the hemi- and southern boreal zones there are 10. The latter two share all taxa.

Skvortsovia: 5(3): 11 – 32 (published on line 15 November 2019)