Vou. IV. ANN ARBOR, OCTOBER, 1884. No. 10. 
WHOLE No. 27. 
Original Communications, 
THE MICROSCOPIC STRUCTURE OF HYDRASTIS 
CANADENSIS. 
BY LOUISA REED STOWELL. 
YDRASTIS CANADENSIS, or Golden Seal, is perhaps the 
most important of American drugs. It is indigenous to 
Canada and the eastern part of the United States. 
The rhizome is from one to two inches long, and about a 
quarter of an inch thick. The cork upon the outside is com- 
posed of from four to eight rows of thin-walled, tabular cells, 
of a dark brown color, with broken and irregular walls; the 
outer edge of the cells frequently being darker than the inner. 
The green layer of the bark is composed of from twelve to 
fifteen rows of oval, clear white, thin-walled cells of parenchy- 
ma, loaded with starch grains, chlorophyl bodies, oi], and: pro- 
toplasm. The corners of these cells are thickened, leaving 
many little open spaces between the cells. The liber layer of 
the bark is very similar to the green layer, only that the cells 
are more compressed, fitting into each other so closely as to 
leave no intercellular spaces. 
