Fig. 2 Correlations between floral volume and (a) daily nectar sugar mass in 46 flowering species, and (b) pollen volume in 33 flowering species; with (c) a diagram of floral volume measurements using the volume of an elliptic cylinder (\(\mathrm{V}\mathrm{\ }\mathrm{=}\mathrm{\ }\mathrm{\pi}\mathrm{\text{abh}}\)). Black lines in (a) and (b) represent linear model estimates of nectar mass or pollen volume by floral volume; shaded areas are 95% confidence intervals. Note logarithmic axes.