Iris. Fig. 2.—Small portion of cross-section

Fig. 2.—Small portion of cross-section of same rhizome more highly magnified, showing portions of cortex, cylinder-sheath and central cylinder.
a, intercellular space in cortex;
b, cylinder-sheath;
c, xylem of one of the bundles. in exterior portion of central cylinder. Magnification, 100 diameters.

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