Plate 15. Microscopic structure of the rhizome of Coptis trifolia.

A, cross section of the rhizome; B, longitudinal section of the rhizome.
A—Drawn with the 2/3-in. objective and the "A" eye-piece.
B—Drawn with the 2/3-in. objective and the "C" eye-piece.

LETTER REFERENCES TO PLATE XV AND FIGS. 54, 56, 59, 60, 61, AND 62.—
a, epidermis; b, parenchyma; c, endodermis; d, phloëm; e, liber fibre; f, pitted cells; g, medullary rays; h, wood prosenchyma; i, reticulated cells of parenchyma; k, pith parenchyma; l, spiral vessels; m, resin; n, cells filled with yellow coloring-matter; o, oil-bearing parenchyma; p, palisade tissue; r, cuticle; s, starch or starch-bearing parenchyma; t, root-hairs; v, chlorophyll-bodies; w, stomates. This image is from Coptis in the Drugs and Medicines of North America.