Calamus, or sweet flag, is a perennial plant often found in damp and marshy environments across Asia, Europe, and North America. Botanically known as *Acorus calamus*, it has a long history of use in traditional medicine and aromatherapy. Characterized typically by its sword-shaped leaves and a knobby rhizome, calamus emits a distinctive scent that is earthy, sweet, and slightly spicy.
The scent profile of calamus is complex and has been noted for its aromatic similarity to cinnamon, though decidedly woodier and with hints of ginger. When the roots (rhizomes) are dried and used in perfumery or essential oils, they release a warm, balsamic fragrance that often carries a subtle undertone of leather. This makes calamus a favored note in oriental and woody perfume accords. Its essential oil is also described as having refreshing and invigorating top notes with rich, sweet balsamic undertones, making it intriguing for use in scent compositions and therapeutic applications alike.