Box plot of biomass yields for upland and lowland cultivars of switchgrass. Bold horizontal lines indicate the median for each cultivar. Boxes represent the interquartile range (IQR, or middle 50%) of the yield values for each cultivar. Vertical whiskers extend to the furthest values up to 1.5 IQR. Additional points are shown as outliers. Box widths are proportional to the number of observations for each cultivar. Cultivars are grouped by ecotype, with gray horizontal lines indicating the median yield across cultivars within each ecotype.