O. arbutifolius n=16 ref Stoutamine & Beaman 1960; Beaman et al. 1962

O. glanduliferus n=16 ref Beaman et al. 1962; Turner et al. 1962

O. oaxacanus n=16 ref King et al. 1976

References

Beaman, J. J., D. C. D. Dejong, and W. P. Stoutamire. 1962. Chromosome studies in the alpine and subalpine floras of Mexico and Guatemala. American Journal of Botany 49: 41-50.

King, R. M., D. W. Kyhos, A. M. Powell, P. H. Raven, and H. Robinson. 1976. Chromosome numbers in Compositae. XIII. Eupatorieae. Annals of the Missouri Botanical Garden 63: 862-888.

Stoutamire, W. P. and J. J. Beaman. 1960. Chromosome studies of Mexican alpine plants. Brittonia 12: 226-229.

Sundberg, S., C. P. Cowan, and B. L. Turner. 1986. Chromosome counts of Latin American Compositae. American Journal of Botany 73: 33-38.

Turner, B. L., A. M. Powell, and R. M. King. 1962. Chromosome numbers in the Compositae VI. Additional Mexican and Guatemalan Species. Rhodora 64: 251-271.

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.