Clade accumulation curves. Clade accumulation curves for A) T. villosus and B) S. mucronata obtained by 1000 resamples. For each clade level, the observed number of clades is indicated by a horizontal line. The average number of sampled clades per site sampled is represented by a solid curve, the respective upper and lower 95% confidence limits by hatched lines. Saturation as indicated by the convergence of the confidence lines on the observed values is reached for both species on the 3-step level.