Armed with more robust phylogenetic hypotheses, it has been possible to examine with more precision the evolution of chromosomes within Melampodium. Analyses have revealed that the base number of the genus is x = 11 (the same number observed in the related genera Acanthospermum and Lecocarpus), other base numbers (x = 9, 10, 11, 12, 14) originating via descending or ascending dysploidy. Of particular interest are the origins of the tetraploid and hexaploid species in Sect. Melampodium Ser. Sericea. For instance, the diploid species M. linearilobum, with very small chromosomes, has been involved with the origin of the allotetraploid M. nayaritense and the allohexaploids M. sericeum and M. pringlei. Evidence of these origins has come from phylogenetic analyses and molecular cytogenetic methods using in situ DNA hybridization, including both mapping of rRNA genes via FISH (fluorescent in situ hybridization) and “chromosome painting” (genomic in situ hybridization; GISH), plus genome size measurements.