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Leaf Thickness by Exposure and Species
by Bob Harms
B. trifoliolata leaflet lamina X-cut.
Lamina Thickness
Measurements of lamina thickness, in the chart below, show:
- A clear effect of sun/shade exposure, especially with B. trifoliolata
- No difference for terminal vs. lateral leaflets
- Hybrids as a class show considerable overlap with B. trifoliolata and B. swaseyi, without matching these at sun & shade extremes
Lamina thickness (mm.), terminal and paired leaflets measured separately.
Midrib Prominence
The relative prominence of the midrib vein might well have influenced impressionistic judgments as to leaf thickness. Thickness measurements were made at the midrib and then at the lamina 1 mm to its left and right (averaged). The lamina thickness was subtracted from the midrib thickness as an index of relative midrib prominence. The results showed no significant difference among our species. (For an illustration of how the midrib/lamina measurements were made.)
Midrib thickness less lamina thickness at 1 mm to the side.