Structure. � Rhizome: a few rows of grayish, tabular cork cells; a cortex made up chiefly of parenchyma containing starch, large cells containing raphides of calcium oxalate and small isolated groups of fibers and stone cells; a wood cylinder composed of slender wedges of tracheae and tracheids separated by medullary rays 1 to 3 cells in width, the cells of the latter containing starch grains; pith of large polygonal cells with prominent simple pores.

Powdered Hydrangea. � Light yellowish; irregular fragments consisting of strongly lignified tracheae with reticulate thickenings, tracheids and medullary ray cells; strongly lignified stone cells and fibers from 0.030 to 0.200 mm. in length, the walls marked with simple or branching pores; raphides of calcium oxalate numerous from 0.050 to 0.135 in length; starch grains mostly single, ellipsoidal, up to 0.010 mm. in diameter, occasionally with a prominent central cleft." N.F.

Bondurant (A. J. P., 1887, 122) isolated a characteristic glucoside, hydrangin, crystallizing in stellate clusters, melting at 235� C., and subliming without decomposition. It is decomposed by dilute acids into a resin-like body and glucose. Its aqueous solution fluoresces strongly on addition of an alkali, resembling aesculin, but distinctly different in several particulars. Bondurant also obtained a fixed oil and a volatile oil, the latter containing sulphur. Two resins seemed also to be present, together with saponin and sugar. He found no tannin, however. Y. Asahina has isolated two crystalline substances from the alcoholic extract of the flowers of H. Hortensia, the Chinese plant which is widely cultivated as an ornamental shrub in this country, hydragenol and hydrangeaic acid.

Uses. � Hydrangea is said to have been used by the Cherokee Indians. It was at one time used in medicine in the treatment of stone in the bladder and cystitis but has been largely abandoned. In overdose it is said to cause vertigo and oppression of the chest.

Off. Prep.� Fluidextractum Hydrangea, N. F.; Elixir Hydrangeas et Lithii, N. F. (q.v.) Use the site search box. Top right hand of the page.

History. The Hydrangeas are marsh or aquatic plants, and hence the name is derived from a Greek compound signifying water vessel. Four of the known species are natives of America; one, the garden Hydrangea (Hydrangea hortensis), is widely cultivated in the gardens of China and Japan. Many methods are employed in this country for imparting the blue tinge to its petals. The oak-leaved Hydrangea (H. quercifolia), a native of Florida, is also cultivated for its beauty.

The bark of H. arborescens is rough, with a tendency to peel, each layer being of a different colour, from which it has probably derived its name 'Seven Barks.' The roots are of variable length and thickness, having numerous radicles, reaching a diameter of more than half an inch. They are externally pale grey, tough, with splintery fracture; white inside, without odour, having a sweetish, rather pungent taste. When fresh, the root and stalks are very succulent, containing much water, and can easily be cut.

When dry, they are tough and resistant, so that they should be bruised or cut into short, transverse sections while fresh. The taste of the bark of the dried root resembles that of cascarilla. The stalks contain a pith which is easily removed, and they are used in some parts of the country for pipe-stems.

Constituents. The root has been found to contain two resins, gum, sugar, starch, albumen, soda, lime potassa, magnesia, sulphuric and phosphoric acids, a proto-salt of iron, and a glucoside, Hydrangin. No tannin has been found, but a fixed oil and a volatile oil have been obtained. From the alcoholic extract of the flowers of H. hortensia, two crystalline substances were isolated, Hydragenol and Hydrangeaic acid.

Medicinal Action and Uses. Diuretic, cathartic, tonic. The decoction is said to have been used with great advantage by the Cherokee Indians, and later, by the settlers, for calculous diseases. It does not cure stone in the bladder, but, as demonstrated to the medical profession by Dr. S. W. Butler, of Burlington, N.J., it removes gravelly deposits and relieves the pain consequent on their emission. As many as 120 calculi have been known to come from one person under its use. The fluid extract is principally used for earthy deposits, alkaline urine, chronic gleet, and mucous irritations of the bladder in aged persons. A concentrated syrup with sugar or honey, or a simple decoction of the root, may also be used.

In overdoses, it will cause vertigo, oppressions of the chest, etc. The leaves are said by Dr. Eoff to be tonic, silagogue, cathartic and diuretic.