Fig. 1. Morphology of the orthotropic main stem of 5‐year‐old W. nobilis plants from which the leaf axils were excised. A, Leader apex (Position 1) showing the typical deposition of resin that occurs when an apex is not elongating. The white exudate (arrowed) is resin from where leaf axils had been excised. Stem diameter 2 cm. B, Midway between the apex and base (Position 5). Note the periderm formation on the leaf bases, while the tips are still green. The white square (arrowed) is where an axil had been excised. Stem diameter 3·2 cm. C, Base of plant (Position 10) with remains of the leaves arrowed. Stem diameter 4·5 cm.