Chromosome numbers of some North American Salix

Chromosome numbers are reported for 19 species of North AmericanSalix, one natural hybrid, and one introduced species. The following 17 species are here examined cytologically for the first time:Salix amygdaloides Anderss.,S. arbusculoides Anderss.,S. brachycarpa Nutt.,S. Candida Willd.,S. discolor Muhl.,S. exigua Nutt.,S. kumilis Marsh.,S. interior Rowlee,S. lutea Nutt.,S. maccalliana Rowlee,S. monticola Rydb.,S. myrtillifolia Anderss.,S. pellita Anderss.,S. petiolaris J. E. Sm,S. scouleriana Barr.,S. silicicola Raup, andS. subcoerulea Piper. Of the 19 native North American species 11 are diploid, four are tetraploid, one is triploid, one hexaploid, one dodecaploid, and one exhibits more than one ploidal level.