Figure 1
From: The arrangement of lateral veins along the midvein of leaves is not related to leaf phyllotaxis
Arrangement of lateral secondary veins along the midvein. Leaves of Ulmus are shown as examples. In the panel (a), dopposite is the distance between the first lateral vein (1) and the next lateral vein (2) on the opposite side of the central vein, and dsame is the distance between the first lateral vein (1) and the next lateral vein (3) on the same side of the central vein. For each lateral vein, the ratio (r) is calculated as dopposite divided by dsame. (a) r ≈ 0.5 indicates that a lateral vein on one side of a leaf lamina originated from approximately halfway between the two points of origin of the lateral veins on the opposite side. (b) r ≈ 0 or r ≈ 1 indicates that a lateral vein on one side of a leaf lamina originated at approximately the same point as the other lateral vein on the opposite side. (c) We also observed a few cases in which two successive lateral veins were on the same side of a leaf lamina. This irregular pattern is expressed as r > 1. (Photographs by Kohei Koyama).
