Prunus. Fig. 11.—Cross section of stem bark of Prunus Pennsylvanica.

Fig. 11.—Cross-section of the stem bark of Prunus Pennsylvanica magnified about 75 diameters.
a, cork in layers, represented as separating from the middle bark,
b; c, irregular or tortuous sclerenchyma fibres;
d, medullary ray;
g, fissure between medullary ray and bast;
h, compressed sieve tissue;
i, young bast tissues near cambium;
k, cambium zone;
l, a duct in the wood.

This image is from Structure of our Cherry Barks in the September issue of the American Journal of Pharmacy, 1895.