Probable Base Number for Genus x = 10
B. condolleana 2n=ca 30 I ref Sundberg et al. 1986
B. organensis n=10 ref Coleman 1970 (reported as Eupatorium organense)
References
Coleman, J. R. 1968. Chromosome numbers in some Brazilian Compositae. Rhodora 70: 228-240.
Coleman, J. R. 1970. Additional chromosome numbers in some Brazilian Compositae. Rhodora 72: 94-99.
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.
Sundberg, S., C. P. Cowan, and B. L. Turner. 1986. Chromosome counts of Latin American Compositae. American Journal of Botany 73: 33-38.