Calamus Aromaticus, Sweet Flag, or Sweet Rush: A genus of the monogynia order, belonging to the hexandra clas of plants; and ranking in the second natural order, Piperae. The characters are: The calyx is a cylindric simple spadix covered with florets; there is no spathe, nor perianthium. The corolla is composed of five obtuse, concave, loose petals. The filaments consist of five thickish filaments, somewhat longer than the corolla; the antherae are thickish and didymous. The pistillum has a gibbous oblong germen the length of the filaments; no stylus; the stigma a prominent point. The pericarpium is a short triangular, obtuse, three-celled capsule, attenuated at both ends. The seeds are numerous, and of an oblong egg-shape.

There is but one species, the acorus calamus. It grows naturally in shallow standing waters, and is found wild in some parts of Britain. It grows plentifully in rivulets and marshy places about Norwich and other parts of this island, in the canals of Holland, in Switzerland, and in other countries of Europe. The flags have been usually supplied from the Levant with dried roots, which do not appear to be superior to those of our own growth. The leaves are sometimes two feet long, narrow, compressed, smooth, and of a bright green, terminating in a point; the root is pretty long, of a whitish, reddish, and partly greenish colour. Among the leaves there arises a single one, thicker and more robust than the rest, furrowed on the surface, and of a paler green. On this grow frequently two spikes of flowers, by many writers called juli. These are of a brown colour, having a chequered surface. The root of this plant has a very agreeable flavour, which is greatly improved by drying. It is reckoned carminative and stomachic, having a warm, pungent, bitterish taste; so is frequently used as an ingredient in bitters. It has been complained of, however, as communicating a nauseous flavour to those bitters in which it was infused; and Neumann observes, that its agreeable flavour, as well as its distinguishing taste, reside entirely in a volatile essential oil; the residuum after distillation having a nauseous flavour, not at all resembling that of the calamus. It is an ingredient in the mithridate and theriacs of the London pharmacopoeia; and in the aromatic and stomachic tinctures, and compound arum powder, of the Edinburgh. The fresh root candied is said to be employed at Constantinople as a preservative against epidemic diseases. The leaves of this plant have a sweet fragrant smell, more agreeable, though weaker, than that of the roots. Neither horses, cows, goats, sheep, nor swine, will eat the herb, or its roots.

Culture. The acorus being a perennial plant, may be transplanted into a garden, where it will thrive very well if the ground is moist; but never flowers unless it grows in water. It loves an open situation, and will not thrive well under the shade of trees. The flowers appear the latter end of June, and continue till August.

in the materia medica, a name sometimes given to the great galangal. See KEMPERIA.

in natural history, blue coral. The true sort is very scarce; some, however, is fished on the coasts of Africa, particularly from Rio del Re to the river of the Camarones. This coral is part of the merchandise which the Dutch trade for with the Camarones; that of the kingdom of Benin is also very much esteemed. It grows in form of a tree on a rocky bottom.