evolutionary relationships, while different chromosome numbers may suggest distant relationships through reproductive isolation. Chromosome counts have been studied extensively in North America; all Solidago species have a base chromosome number of x=9, but the following ploidy levels have been observed: 2x, 3x, 4x, 6x, 8x, 10x, 12x, and 14x. Though negligible differences in karyotype among Solidago and related genera were found, Solidago taxa with multiple cytotypes are more common than those with one. Although chromosome count is a useful metric for differentiating among Solidago taxa, it may be problematic due to the frequent variation in ploidy levels. Cytogeographic patterns in the Solidago gigantea complex, with tetraploids occurring in eastern North America and hexaploids in Oregon and Washington, were observed. Cytogeographic patterns are also observed in the Solidago canadensis complex: hexaploids within S. canadensis have been observed east of the Great Plains and are treated as Solidago altissima, and diploids and tetraploids occurring in the Great Plains are treated as Solidago gilvocanescens. The taxonomic status of Solidago ptarmicoides created an extensive debate due to frequency hybridization of S. ptarmicoides with members of the Ptarmicoidei section of Solidago. It was asserted that S. ptarmicoides should be united with Solidago rather than the genus Aster due to external morphological features such as similar pappus length as well as the same chromosome base (x=9). Information about chromosome number is still a crucial part of current understanding and phylogenies of Solidago. Use and cultivation Young goldenrod leaves are edible. Traditionally, Native Americans use the seeds of some species for food. Herbal teas are sometimes made with goldenrod. Goldenrod often is inaccurately said to cause hay fever in humans. The pollen causing this allergic reaction is produced mainly by ragweed (Ambrosia sp.), blooming at the same time as the goldenrod and pollinated by wind. Goldenrod pollen is too heavy and sticky to be blown far from the flowers, and is pollinated mainly by insects. Frequent handling of goldenrod and other flowers, however, can cause allergic reactions, sometimes irritating enough to force florists to change occupation. Goldenrods are attractive sources of nectar for bees, flies, wasps, and butterflies. Honey from goldenrods often is dark and strong because of admixtures of other nectars. However, when honey flow is strong, a light (often water-clear), spicy-tasting monofloral honey is produced. While the bees are ripening the honey produced from goldenrods, it has a rank odour and taste; the finished honey