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 common or Roman chamomile, Anthemis nobilis, Linne (N.O. Compositoe), is a small creeping perennial plant with shortly ascending, leafy, flowering branches, bearing terminal white-rayed flowerheads. It is common on waste grounds in this country, and is cultivated for medicinal use both in England (Hampshire, etc.) and in Belgium, France, and Saxony. Formerly large quantities were produced near Mitcham, but at present there is but little grown in Surrey, and that little is used chiefly for distillation. The flowers have been used for centuries as a domestic medicine.
Fig. 39. - Single chamomile. A, entire; B, cut vertically, showing the solid, conical receptacle. Natural size. (Bentley and Trimen).
The inflorescence of the wild plant is a capitulum surrounded by two or three rows of overlapping bracts; the disc-florets are yellow, tubular, closely packed on an elongated conical receptacle and surrounded by a single row of ray-florets with white ligulate corollas. Such chamomile flowers, which are properly designated ' single,' are collected to some extent in Scotland, but they are not official.
Under certain circumstances the flower may become more or less double. The yellow tubular corollas of the disc-florets become more or less completely white and ligulate, and the flowerhead is converted into a hemispherical mass of white ligulate florets. These are ' double ' chamomiles, and form the bulk of the imported, cultivated flowers; intermediate forms, or semi-double flowers, in which the conversion of tubular into ligulate corollas has been only partially effected, may, however, frequently be found.
The entire flowerhead is collected and dried.
The official chamomiles are limited to the 'double' or semi-double flowerheads obtained from cultivated plants, those imported from Belgium, France, and Saxony being preferred by the drug trade on account of their handsome appearance, whilst English flowers yield more volatile oil when distilled.
The flowerheads are hemispherical in shape, 10 to 20 mm. in diameter, and white or nearly white in colour, becoming yellow or buff-coloured when kept. The involucre surrounding each flowerhead consists of two or three rows of overlapping bracts with membranous margins, and is almost entirely concealed in the drug by the reflexed outer ligulate florets. The latter are pistillate, the yellow tubular central florets (if present) being hermaphrodite. The corolla of the ligulate florets is white, rather narrow, and terminated by three teeth; towards the base it is contracted to a short tube, immediately below which is the small, nearly smooth ovary. The calyx is completely adherent to the ovary, and, there is no pappus. If the florets are all carefully plucked from the flowerhead, a number of blunt, narrow, concave, scaly bracts (paleae) with membranous wings will be found standing on a conical receptacle; on cutting a flowerhead longitudinally through the centre each floret will be seen to spring from the axil of a bract, and the conical receptacle will be found to be solid (or occasionally lacunous). When closely examined with a powerful lens, the lower part of the corolla may be seen to be sprinkled with minute, yellowish, shining oil-glands.
Chamomiles have an aromatic odour and an aromatic, intensely bitter taste.
The student should carefully strip the florets from a flowerhead, and observe
(a) The presence and shape of the paleoe; and should also cut a flowerhead longitudinally through the centre, and note
(b) The solid, elongated, conical receptacle.
He should further compare these with those of the flowers of the wild chamomile, German chamomile (Matricaria Chamomilla, Linne), and of the feverfew (Chrysanthemum Parthenium, Bernhardi), which are alluded to below. He should also soak a few ligulate florets in water, spread them out on a dark surface and examine the three-toothed apex.
Fig. 40. - Double chamomile. Natural size. (Bent-ley and Trimen).
The principal constituents of chamomile flowers are the volatile oil (0.8 to 1.0 per cent.) and the bitter principle, anthemic acid.
The volatile oil is blue when freshly distilled, but becomes greenish or brownish yellow on keeping; it consists chiefly of the esters of the isomeric acids angelic and tiglic, with butyl and amyl alcohols; it also contains an alcohol, anthemol, and a crystalline hydrocarbon, anthemene.
Fig. 41. - Chamomile (Anthemis nobilis). A, ray-floret, magnified 4 diam. B, disc -floret with bract (b), showing external glands; more highly magnified. (Luerssen).
Fig. 42. - German chamomile (Matricaria Chamomilla). A, flowerhead cut vertically. B, ray-floret, magnified. (Moeller).
Anthemic acid is an intensely bitter, crystalline glucoside easily hydrolysed with total loss of bitterness, prolonged boiling in water being sufficient to produce the reaction.
The flowers also contain a crystalline phytosterin, anthesterin, melting at 221°, wax, fatty oil, glucose, etc. They yield about 5 per cent, of ash.
Chamomile flowers possess aromatic, bitter stomachic properties; the oil is occasionally administered in pills as a carminative.
The characters given above will easily distinguish the true or Roman chamomile from the following, which somewhat resemble it:
The flower-heads are smaller, single, and have a hollow conical receptacle devoid of palese. They are sometimes sold as ' single chamomiles.'
The cultivated plant has double flowerheads, resembling those of the chamomile. The receptacle is flat; paleae may be present or absent, according to the variety; if present they are acute.