THE EPIDERMIS AND PERIDERM 63 
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, bella- 
donna, 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 in- 
dicated 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, com- 
posed 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 out- 
line, 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. 
