Probable Base Number for Genus x = 12
M. mexicana 2n=24 + 4-8 Bs ref Watanabe et al. 2007
References
Robinson, H., A. M. Powell, G. D. Carr, R. M. King, and J. F. Weedin. 1989. Chromosome numbers
in Compositae, XVI: Eupatorieae II. Annals of the Missouri Botanical Garden 76: 1004-1011.
BLT 1997, Turner, B. L. 1997. The Comps of Mexico. Eupatorieae. Phytologia Memoirs Vol. 11.
Watanabe, K., T. Yahara, G. Hashimoto, Y. Nagatani, A. Soejima, T. Kawahara, and M. Nakazawa. 2007.
Chromosome numbers and karyotypes in Asteraceae. Annals of the Missouri Botanical Garden 94: 643-654.