It has a very irregular external form, being sometimes cylindrical, at others, tuberculated. Its taste is strongly astringent, and its odor faintly aromatic. It is equally applicable in medicine with catechu, kino, and other foreign astringents. When the tannic acid is heated with diluted sulphuric acid, insoluble tormentilla-red , a phlobaphene, but no sugar, is formed. Fused with caustic potash, it forms phloroglucin and protocatechuic acid .
Calcium oxalate is also a constituent of the root.
Action, Medical Uses, and Dosage. Alum or tannic acid may be added to this, as required. It has a sarmentose, procumbent and ascending stem 2 to 18 inches in length. Stipules ovate, hairy, deeply 2 or 3-cleft, or entire. Flowers yellow, on long, axillary, solitary pedicels.