This section is from the book "A Text Book Of Materia Medica, Being An Account Of The More Important Crude Drugs Of Vegetable And Animal Origin", by Henry G. Greenish. Also available from Amazon: A Text Book of Materia Medica : Being an Account of the More Important Crude Drugs of Vegetable and Animal Origin.
The red or Provins rose, Rosa gallica, Linne (N.O. Rosaceoe), is probably indigenous to southern Europe, but has been cultivated as a garden plant in numerous varieties everywhere. For medicinal use the red rose is grown in England (Oxfordshire, Derbyshire, &c), in the south of France, near Hamburg, etc.
The drug is collected by plucking the whole of the unexpanded petals from the calyx. The little masses of petals are then either used fresh for the preparation of the confection, or dried, in which state they are officially employed for making the infusion; in the latter case they are often gently sifted to remove the stamens. The petals of the red rose are obovate in outline, velvety, and of a deep purplish red colour, with a paler claw.
When collected as described they remain united in small conical masses of a deep purplish red colour, paler towards the base; these, however, are often broken up into the separate petals for convenience in use. They possess a delicate rose-like aroma and slightly astringent taste.
Red-rose petals contain a trace of volatile oil, gallic and possibly quercitannic acids. The colour is due to the glucoside cyanin (microcrystalline, dark brown powder, 2 per cent.) which is probably combined with an acid; when present as a potassium salt (as in cornflowers) cyanin produces a dark blue colour. The crystalline yellow substance obtained by Naylor and Chappel (1904) was probably a decomposition product of cyanin.
Red-rose petals should have attached a portion of the paler base of the petal. Artificially coloured petals, may be recognised by their uniform dark reddish colour.
The petals are slightly astringent; they are chiefly used medicinally, in the form of acid infusion, as an agreeable astringent vehicle or as a colouring agent.
Rosa centifolia, Linne, largely cultivated as a garden plant, has pale red or pink petals formerly official for the production of rose water.
Rosa damascena, Linne, largely cultivated in European Turkey, Bulgaria, the south of France, etc, yields otto of rose and is the rose from which rose water is officially. prepared.