Calamus
Calamus names 3 different subjects across the 6 encyclopedias on this shelf. Each is set out below.
Calamus the traditional name of the sweet flag (acorus calamus)
Collier's New Encyclopedia (1921)
the traditional name of the sweet flag (acorus calamus), which is no doubt the "calamus aromatic aromaticus" of Roman authors, and probably the sweet calamus and sweet cane of Scripture, although it has sometimes been attempted to identify calamus with one of the fragrant grasses which yield the grass-oil of India. The sweet flag, although resembling Iris in habit, belongs to the order Aroideæ, and is widely distributed through the Eastern palæarctic region, and is also indigenous to North America. The root-stock yields an aromatic stimulant and tonic, which has fallen into disuse in regular medicine, but is still of high repute in the East. It is in fact cultivated in Ceylon and Burma. It is sometimes used to flavor beer, and in the perfuming of tooth powder and snuff; and was masticated to clear the voice and sweeten the breath. It is also made into confections and used in the preparation of liqueurs in Germany, etc. The plant was formerly used to strew floors instead of rushes, and particularly in cathedrals on festival days. The name calamus is also given to a genus of palms.
Calamus the reed pen which the ancients used in writing
Collier's New Encyclopedia (1921)
the reed pen which the ancients used in writing, made of the stem of a reed growing in marshy places, probably Arundo Donax, of which the best were obtained from Egypt. The stem was first softened, then dried, and cut and split with a knife (scalprum librarium), as quill pens are made. To this day the Orientals generally write with a reed (Arab. Kalam).
Calamus . See Sweet Flag
Aiton's Encyclopedia (1910)
. See Sweet Flag
What Has Changed in the Last Century
When Collier's wrote this in 1921 the sweet flag was placed in the "order Aroideae" alongside the arums; molecular work since the 1990s has instead put Acorus in a family of its own, Acoraceae, as the sister lineage to all other flowering monocots — the deepest branch on that part of the tree. The old account's cheerful list of uses — flavouring beer, confections, German liqueurs, tooth powder — has largely ended in the West: the rhizome contains beta-asarone, shown to be carcinogenic in rodents, and the US Food and Drug Administration banned calamus as a food additive in 1968. Chemistry has since shown the plant is not uniform: the diploid North American race is essentially free of beta-asarone, while European and Asian polyploid forms carry it, so the risk depends on which calamus you have. The reed-pen entry still stands, and the palm genus Calamus mentioned in passing turns out to be the largest of all palm genera and the source of nearly all commercial rattan.
Written for this edition, 2026.