Probable Base Number for Genus x = 9
P. pluriseta n=9 ref King et al. 1976
References
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.
BLT 1997, Turner, B. L. 1997. The Comps of Mexico. Eupatorieae. Phytologia Memoirs Vol. 11.