References
Chambers, H., and J. Hamer. 1992. More about picky Pycnanthemums; can taxonomy be practical after all? Tipularia 7: 19-24. Google Scholar
Chambers, H., and J. Hamer. 1992. More about picky Pycnanthemums; can taxonomy be practical after all? Tipularia 7: 19-24. Google Scholar