Probable Base Number for Genus x = 10
I. microcephala n=10 ref Keil & Stuessy 1981
I. oppositifolia n=10 ref King et al. 1976; Keil & Stuessy 1981; Robinson et al. 1989
References
Keil, D. J. and T. F. Stuessy. 1981. Systematics of Isocarpha (Compositae: Eupatorieae). Systematic
Botany 6: 258-287
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.
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.
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.