The Elder: Paired Leaves That Bend to Catch the Dew
Crossed leaf-pairs on the upright stem, and why the lower branch stops crossing
Illustrated by drawn elder branches in the right margin, Leonardo describes how the elder sets its leaves two by two in crossed pairs. When the stem rises straight toward the sky this order never fails, the larger leaves on the thicker part of the stem and the smaller toward the top. On the lower branch, however, the leaves that would cross as on the upper branch are constrained by the general law that leaves must turn their faces to the sky to take the night dew, so their placements bend and no longer cross.
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Crossed leaf-pairs of the elder, and where crossing fails
The elder sets its leaves two by two, each pair crossing the one above; on an upright stem this order never fails, larger leaves below and smaller toward the top. On the lower branch, though, the leaves must turn their faces to the sky to catch the night dew, so instead of crossing they bend out of that arrangement.