Vitekorchis excavata: habit and LM. (A, B) Flower prior to (A) and following treatment with Sudan III (B) showing distinctly stained, lipid-rich callus region (arrow). (C) Section of callus showing glabrous, abaxial and papillose, adaxial epidermis. Note that the callus projection lacks papillae. (D) Epidermal papillae contain intravacuolar anthocyanins, whereas large idioblasts occurring in the ground parenchyma contain raphides. (E) Plastids in parietal cytoplasm following staining with MB/AII. (F) Surface and intracellular lipids stained with Sudan III. These compounds occur in both epidermal papillae and sub-epidermal cells. (G, H) Starch grains present in glabrous epidermal cells, papillae and parenchyma cells stain with the PAS reaction. Note the weak staining of large idioblasts and vascular bundles near the abaxial epidermis (H). Scale bars = 1 cm, 1 cm, 500 μm, 50 μm, 20 μm, 50 μm, 100 μm, 100 μm, respectively. R, idioblasts with raphides; Vb, vascular bundle.