Iris. Fig. 5.—Portion of cross-section of root

Fig. 5.—Portion of cross-section of root of Iris versicolor, magnified 100 diameters.
a, epidermis;
b, cell of cortical parenchyma;
c, large duct in vasal-bundle;
d, endodermal cell;
e, pericambium cell;
f, small ducts at exterior end of xylem ray.

This image is from Structure of Iris. in the American Journal of Pharmacy, 1895.