Fig. 1.

Comparative view of leaf morphology of (A, C) Cattleya walkeriana and (B, D, E) Oncidium ‘Aloha’. Light micrographs, transverse (A–D) and longitudinal (E) sections. (A, B) General view of transverse sections from the middle region of leaves showing the succulent morphology of Cattleya leaf (A) and the non-succulent constitution of Oncidium leaf (B). (C, D) Transverse sections from the leaf blade showing the epidermis of Cattleya covered by thicker cuticle on both surfaces (C) and the aerenchyma (arrow) between vascular bundles in Oncidium leaf (D), with detail of the aerenchyma near the pseudobulb (arrow) in a longitudinal section at the leaf base (E).