Probable Base Number for Genus x = 12
M. flaccidum n=12 ref cf BLT 1997
M. nummulariifolium 2n=24; 2n=36 ref Sundberg et al. 1986; Strother & Panero 2001; Watanabe et al. 2007
References
BLT 1997, Turner, B. L. 1997. The Comps of Mexico. Eupatorieae. Phytologia Memoirs Vol. 11.
Strother, J. L. and J. L. Panero. 2001. Chromosome studies: Mexican Compositae. American Journal of Botany 88: 499-502.
Sundberg, S., C. P. Cowan, and B. L. Turner. 1986. Chromosome counts of Latin American Compositae. American Journal of Botany 73: 33-38.
Watanabe, K., R. M. King, T. Yahara, M. Ito, J. Yokoyama, T. Suzuki, and D. J. Crawford. 1995. Chromosomal cytology and evolution in
Eupatorieae (Asteraceae). Annals of the Missouri Botanical Garden 82: 581-592.