Table II. Quantifying the artifacts of the approach of Price et al. (2014)

Errors include the use of low-magnification 5× images with veins not discernible, inclusion of and veins in images, and the errors arising from four artifacts in the LEAFGUI algorithms, all of which lead to inaccurate estimation of leaf VLA and the illusion of a dependency of VLA on image magnification. For each artifact, the effect on VLA was determined for the one image per leaf per species at each of three magnifications measured by Price et al. (2014). The total LEAFGUI error was determined by adding the missing vein length due to the thresholding artifact and the neglected vein length artifact and subtracting the vein length due to the false vein artifact and the zigzag line artifact. Effects are presented in absolute terms (mm mm−2) and as percentages of total VLA as determined by Price et al. (2014). Error percentages greater than 5% are in boldface. na, Images sufficiently magnified for veins to be discerned.

SpeciesError from Using Low-Magnification Images with Nondiscernible VeinsPercentage of the Image Area Occupied by and Veins; Effect on VLAErrors Arising as Artifacts of LEAFGUI Algorithms
ThresholdingNeglected Vein LengthFalse Vein LengthZigzag LineTotal LEAFGUI Error
B. victoriae
 5×−0.23 (−3.89%)3.0%; +0.32 (+5.4%)−0.28 (−4.9%)−0.077 (−1.3%)0+0.17 (+3.0%)−0.19 (−3.2%)
 20×na3.6%; +0.42 (+6.3%)+0.12 (+1.8%)−0.078 (−1.1%)+0.061 (+0.90%)+0.36 (+5.4%)+0.47 (+6.9%)
 60×na0−0.017 (−0.21%)−0.053 (−0.67%)+0.81 (+10%)+1.1 (+14%)+1.8 (+23%)
H. comptoniana
 5×−0.41 (−6.2%)2.6%; −0.019 (−0.35%)−0.12 (−2.4%)−0.13 (−2.5%)0+0.084 (+1.6%)−0.18 (−3.3%)
 20×na0−0.50 (−7.8%)−0.20 (−3.1%)+0.20 (+3.1%)+0.29 (+4.4%)−0.22 (−3.3%)
 60×na0−0.15 (−2.0%)−0.11 (−1.5%)+0.53 (+7.2%)+0.65 (+8.8%)+0.92 (+12%)
P. alba
 5×−1.6 (−23%)3.4%; −0.018 (−0.38%)+0.64 (+13%)−0.13 (−2.6%)0+0.18 (+3.8%)+0.69 (+14%)
 20×na0−0.41 (−6.3%)−0.11 (−1.7%)+0.083 (+1.3%)+0.54 (+8.4%)+0.11 (+1.7%)
 60×na0−0.027 (−0.34%)−0.022 (−0.27%)+0.27 (+3.3%)+0.83 (+10%)+1.0 (+13%)
P. moluccanum
 5×−0.84 (−13%)0.56%; +0.044 (+1.0%)−1.1 (−25%)−0.20 (−4.7%)0+0.055 (+1.3%)−1.25 (−29%)
 20×na0−0.94 (−18%)−0.083 (−1.6%)+0.13 (+2.4%)+0.32 (+6.0%)−0.58 (−11%)
 60×na0−0.47 (−7.2%)−0.099 (−1.5%)+0.19 (+2.9%)+0.64 (+9.9%)+0.27 (+4.1%)
W. floribunda
 5×−4.2 (−37%)7.3%; −0.21 (−3.3%)−2.6 (−40%)−0.049 (−0.76%)0+0.12 (+1.9%)−2.5 (−38%)
 20×na0−0.85 (−7.7%)−0.22 (−2.0%)+0.15 (+1.4%)+0.88 (+8.0%)−0.039 (−0.35%)
 60×na0−0.47 (−4.0%)−0.15 (−1.2%)+0.28 (+2.4%)+0.97 (+8.2%)+0.62 (+5.3%)