Anatomy. Leaf (fig. 2).—The upper and the lower epidermis consist of large more or less squarish cells with thin walls. There is a thick cuticle on both surfaces. Stomates are found on both faces of the leaf. The guard-cells are level with the upper surface of the epidermal walls, but are below the cuticle. The guard-cells have thickened walls, and the stoma is protected by the guard-cell ridges. The chlorenchyma is rather feebly differentiated. The palisade tissue consists of 4–5 rows of oval cells with very slightly thickened cell-walls, and containing a small number of large chloroplasts. The 2 outer layers of palisadic tissue are compact, but the inner ones are not so closely arranged. There is also palisade tissue on the lower surface of the leaf. Here it is only 1–2 rows of cells. The spongy tissue consists of rather irregular loosely arranged cells, so that there are large intercellular air-spaces. These cells also contain large chloroplasts. Fig. 2.—Hymenanthera dentata var. alpina. Transverse section of lamina of leaf (× 230). a, thick cuticle; b, palisade parenchyma; c, bundle-sheath; d, xylem; e, phloem; f, guard-cell ridge. The vascular bundle is of the usual dicotyledonous type; the amount of lignified tissue in the xylem is small. Surrounding the bundle is a sheath of large thin-walled cells, which are practically devoid of chloroplasts. Stem (fig. 3).—The cork forms a wide band, and consists of fairly large cells with thickened walls. Then comes the phellogen of thin-walled rectangular cells. The cortex forms a layer of tissue 12–14 cells deep; its cells are oval and have thickened walls. There are numerous intercellular air-spaces, most of which are, however, small. Drops of oil are found in the cortical cells. The pericycle fibres form small isolated groups. The cells are small and have very thick walls, so that the cell-cavities are almost obliterated.