The distribution of this rather local aquatic plant, which is known only from its modern occurrence, is N. Temperate Europe (except Greece), N. Asia, eastward to the Himalayas, N. America. In Great Britain it grows in N. Somerset only in the Peninsula province; in N. Wilts, Dorset, Hants in the Channel; in the Thames province, not in Kent, Herts; in Anglia, in W. Suffolk, Cambridge, Hunts, Northampton; in the Severn province, in Warwick, Stafford, Salop; Carnarvon, in N. Wales; in the Trent province, except in Lincs; in the Humber province, except Mid and N.W. Yorks, and elsewhere generally from York and Lancaster to Somerset and Sussex. It is naturalized in Scotland and Ireland. Considered by Bentham native in the East counties, Ludwig says it is descended in Europe from a plant brought by Clusius from the East.

This plant is local, generally, but frequent in some counties. It is entirely aquatic, growing in the water close to the margin of a river, brook, or even ditch, or else it is to be found fringing the sides of a pond, pool, or lake. It is associated with reeds, bulrushes, bur-reeds, growing with them in the marginal reed swamp.

The stem is tall, erect, with the radical leaves clustered round it, and the plant has a grass-like habit. The leaves are long, sword- shaped, flat, with wavy margins, sweet-scented when bruised, like the stem and rhizomes.

Sweet Flag (Acorus Calamus, L.)

Photo. H. Irving - Sweet Flag (Acorus Calamus, L.)

The scape is flattened, long, leafy. The prolongation of it is a spathe which is two-edged. In the spike are several hundred flowers. At its base is a long, slender spadix, which is lateral, and made up of many flowers, curved. The perianth-segments of 6 short scales equal the ovary, and the fruit is inversely egg-shaped.

Sweet Flag is 2-6 ft. high. It flowers in June and July. The plant is a perennial, propagated by division.

The flowers are proterogynous, bisexual or complete, and cross-pollination is ensured. There are 6 stamens, fixed on the base of the segments, with flattened anther-stalks. The 6 stamens with anthers are in pairs, the stigmas sessile and very small. The flowers are sweet-scented. The plant is not usually fertile in the British Isles, as it is in Asia, the proper insects being absent here.

The fruit, which does not ripen in Europe, is a berry, which falls when ripe, being full of mucus, into the water or to the ground, and is thus dispersed.

Sweet Flag is entirely a peat-loving plant, growing in peat soil.

Acorus, Dioscorides, is from acoros, the Greek name of the plant; and Calamus, Dioscorides, is from the Greek calamos, a reed.

Sweet Flag is named Beewort, Cinnamon Sedge, Myrtle and Sweet Flag, Myrtle-flag, Myrtle-grass, Myrtle-sedge, Sweet Seg, Sweet Sedge, Sweet Rush.

Powdered, the root has been used in lieu of spices. It is a stimulant and tonic. When bruised, the leaves smell sweet, hence it was used to strew the floors of houses. It yields an essential oil, obtained by distilling it. It has been used for fevers and ague. The roots are carried abroad, eaten as sweetmeat, and used as a means of avoiding contagion. As orris-root it is used as a tooth powder.

Essential Specific Characters:312. Acorus Calamus, L. - Stem terminating in a spathe, leaves long, ensiform, radical, 2-edged, like the scape, flower (spadix), lateral.