Distributions of pairwise sequence divergence values demonstrating episodes of retrotransposon proliferation in sublineage E'. The x axis represents sequence divergence; y axis represents the frequency of values. (a) Helianthus annuus; (b) Helianthus petiolaris; (c) Helianthus anomalus; (d) Helianthus deserticola; (e) Helianthus paradoxus. Below each distribution is a siZer  map indicating the strength of support for features (peaks) in the distribution. At a given binwidth, features are detected as significant increases in the slope (indicated by blue) followed by significant decreases in the slope (indicated by red). Purple indicates that the confidence interval for the derivative contains zero. Gray indicates insufficient data for analyses.