Spiraea.—Many if not all of the species of this genus contain a colorless volatile oil, very similar to the oil of gaultheria, but composed mainly of salicylic aldehyde, with only smaller amounts of methyl salicylate. The species which have been submitted to actual analysis are the Spiraea Ulmaria L. (Filipendula Ulmaria (L.) Maxim.), commonly known as Queen of the Meadow, or Meadow-sweet—a European plant which has been introduced into this country; also the European species S. lobata Jacq. and the species S. Filipendula L. (Filipendula vulgaris Moench.), which grows in Southern Europe and Northern Africa. A yellow, crystalline powder of a bitter taste, insoluble in water, slightly so in alcohol, readily soluble in ether, and having an acid reaction. Spiraeaic acid (now recognized as salicylic acid) (J. Pr. Chem., xix) was separated from the flowers of S. Ulmaria by Lowig and Weidmann, and has been found by Rochebrune in the flowers of S. Filipendula L.
The roots of probably most of the species contain tannic acid, gallic acid, and when fresh some of the volatile oils. (A. J. P., 1887.) The root of Spiraea tomentosa L. (Hardhack, Steeplebush, or Whitecap), was formerly recognized in the U. S. Pharmacopoeia. It is an indigenous shrub growing in low grounds from New Brunswick and Nova Scotia to the mountains of Georgia and westward. The stems and lower surfaces of the ovate-lanceolate, serrate leaves are whitish and tomentose. The rose-colored flowers are disposed in terminal, compound, crowded spikes or racemes.
The flowers of Spiraea, possess to a very feeble extent the medicinal virtues of salicylic acid, and have been used as diuretic and tonic in the form of decoction. The roots are astringent, and have been used in the treatment of diarrhea in doses of from five to twenty grains (0.32-1.3 Gm.) of the aqueous extract repeated pro re nata.
The Dispensatory of the United States of America, 1918, was edited by Joseph P. Remington, Horatio C. Wood and others.