The difference between Cangpu and Acorus calamus: Acorus calamus, also known as white Acorus calamus and Tibetan Acorus calamus, is a perennial plant with strong roots. Basal leaves are sword-shaped, with prominent midvein, basal leaf sheaths folded and membranous edges. Born in swamps, streams or rice fields.

It is distributed all over China, and also from the former Soviet Union to North America. Like wet, cold-resistant, not choosing soil, strong adaptability, avoid drought. The rhizome is horizontal, the skin is yellow-brown and fragrant. Basal leaves, banded, blade-like spathe sword-shaped, 30-40 cm long, 4-8 em long spike, and yellow-green flowers.