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. 2014 Apr 15;113(7):1155–1173. doi: 10.1093/aob/mcu045

Fig. 7.

Fig. 7.

Oncidium heteranthum var. album: habit and LM. (A) Habit of paniculate inflorescence with branches bearing numerous sterile flowers and few terminal, fertile flowers. (B) Tuberculate callus of fertile flower with projections. Note the tabula infrastigmatica (arrow), which is located on the column. (C) Section of callus projection with overlying glabrous epidermis containing numerous stomata. Idioblasts containing raphides occur in the ground parenchyma. Small quantities of starch, mainly in the sub-epidermal parenchyma, stain with the PAS reaction. (D) Trichomes and papillae occur between the callus projections, whereas idioblasts and occasional starch grains occur in the ground parenchyma. (E) Section of tuberculate callus stained with MB/AII showing vascular bundles that supply the ground parenchyma. None of these vascular elements supplies the sub-epidermis. (F) Callus trichomes stain red with Sudan III, indicating the presence of lipid. Idioblasts with raphides, as well as vascular bundles occur in the ground parenchyma. (G) Small lipid droplets (arrows) occur in the trichomatous and atrichomatous epidermal cells, as well as the sub-epidermal cells. (H) Lipid droplets are also visible within glabrous epidermal cells (arrows). Scale bars = 1 cm, 3 mm, 100 μm, 100 μm, 100 μm, 500 μm, 50 μm, 50 μm, respectively. R, idioblasts with raphides; Vb, vascular bundle.