Of all major taxonomic groups, land plants stand out due to their staggering genome size diversity, ranging ca. 2400-fold. Polyploidy has a direct impact on genome size and—even in the absence of hybridization—it also enhances genetic diversity and genomic dynamism; these can provide new opportunities for gene neofunctionalization and subfunctionalization. Together, these processes have generally been considered as facilitators of adaptation to environmental change and subsequent speciation.