Sweet Flag

Sweet Flag

　　Sweet Flag

　　Sweet Flag is listed as a toxic plant in the Chinese Plant Atlas Database. The entire plant is toxic, with the rhizome being particularly poisonous. Ingesting large amounts can cause intense visual hallucinations. The intraperitoneal LD50 of sweet flag oil in rats is 221 mg/kg, leading to rapid, shallow breathing, intermittent spasms, followed by tonic spasms, and finally death. Intraperitoneal injection of a water extract of the rhizome at 4 g/kg in mice has a sedative effect; the MLD of the alcohol extract is 4 g/kg, and the LD100 is 8 g/kg. The Japanese sweet flag variety can cause gastroenteritis and diarrhea upon poisoning.

　　A perennial aquatic herbaceous plant. It has a fragrant aroma, with creeping, thick, slightly flattened rhizomes that are 0.5–2 cm in diameter and bear numerous adventitious roots (fibrous roots). The leaves are basal, sword-shaped and linear, 50–120 cm long or longer, 1–3 cm wide in the middle, sheathing at the base and clasping the stem, tapering gradually below the middle, with a prominent midrib and raised sides, each side having 3–5 parallel veins; the leaf base has a membranous sheath that later falls off. The flowering stem emerges from the base, is flattened and triangular in shape, 20–50 cm long, with leaf-like spathes 20–40 cm long. The spadix is erect or slightly ascending, cylindrical, yellow-green, 4–9 mm long, 6–12 cm in diameter; the flowers are bisexual, densely clustered, with 6 linear tepals, 2.5 mm long and 1 mm wide; 6 stamens slightly longer than the tepals, with flat filaments and pale yellow anthers; the ovary is elongated-cylindrical, 3 mm long, 1.2 mm in diameter, tapering to a conical tip, with a short style and numerous ovules. The berries are red, oblong, containing 1–4 seeds. Flowering period is June to September, fruiting period is August to October.