The character of the outer wall of the epidermal cells differs greatly in different plants. In most cases the wall is smooth; senna is an example of such leaves. In certain other leaves the wall is rough, the roughness being in the form of striations. In some cases the striations occur in a regular manner; belladonna leaf is typical of such leaves. In other instances the wall is striated in an irregular manner as shown in chirata epidermis. Very often an epidermis is rough, but the roughness is not due to striations. In these cases the epidermis is unevenly thickened, the thin places appearing as slight depressions, the thick places as slight elevations. Boldus has a rough, but not a striated surface. =Surface deposits= are not of common occurrence in medicinal plants; waxy deposits occur on the stem of sumac, on a species of raspberry, on the fruit of bayberry, etc. Resinous deposits occur on the leaves and stems of grindelia species, and on yerba santa. In certain leaves there are two or three layers of cells beneath the epidermis that are similar in structure to the epidermal cells. These are called hypodermal cells, and they function in the same way as the epidermal cells. Hypodermal cells are very likely to occur on the margin of the leaf. Uva-ursi leaf has a structure typical of leaves with hypodermal marginal cells. Uva-ursi, like other leaves with hypodermal cells has a greater number of hypodermal cells at the leaf margin than at any other part of the leaf surface. The cutinized walls of epidermal cells are stained red with saffranin. TESTA EPIDERMIS =Testa epidermal cells= form the epidermal layers of such seeds as lobelia, henbane, capsicum, paprika, larkspur, belladonna, scopola, etc. In surface view the end walls are thick and wavy in outline; frequently the line of union--middle lamella--of two cells is indicated by a dark or light line, while in others the wall between two cells appears as a single wall. The walls are porous or non-porous, and the color of the wall varies from yellow to brown, to colorless. These cells always occur in masses, composed partially of entire and partially of broken fragments. In lobelia seed (Plate 4, Fig. 2) the line of union of adjacent cell walls appears as a dark line. The walls are wavy in outline, of a yellowish-red color and not porous. In henbane seed (Plate 4, Fig. 3) the line of union between the cells is scarcely visible; the walls are decidedly wavy, more so than in lobelia, and no pits are visible. In capsicum seed (Plate 4, Fig. 1) the cells are very wavy and decidedly porous, the line of union between the cell walls being marked with irregular spaces and lines. In belladonna seed (Plate 5, Fig. 1) the walls between two adjacent cells are non-striated and non-porous, and extremely irregular in outline. [Illustration: PLATE 4 TESTA EPIDERMAL CELLS