Feather These barbules have minute hooks called barbicels for cross-attachment. Down feathers are fluffy because they lack barbicels, so the barbules float free of each other, allowing the down to trap air and provide excellent thermal insulation. At the base of the feather, the rachis expands to form the hollow tubular "calamus" (or quill) which inserts into a follicle in the skin. The basal part of the calamus is without vanes. This part is embedded within the skin follicle and has an opening at the base (proximal umbilicus) and a small opening on the side (distal umbilicus). Hatchling birds of some
Acorus calamus widely and frequently used herbal medicines among the Chipewyan people. The Potawatomi people powdered the dried root and placed this up the nose for catarrh. This plant is sometimes used as a pond plant in horticulture. There is at least one ornamental cultivar known; it is usually called 'Variegatus', but the RHS recommends calling it 'Argenteostriatus'. Both triploid and tetraploid "A. calamus" contain alpha-asarone. Other phytochemicals include: Diploids do not contain beta-asarone (β-asarone). The calamus has long been a symbol of love. The name is associated with a Greek myth: Kalamos, son of the river-god Maeander, who loved the youth