The dried scraped peel of the inner bark of the Cinnamomum zeylanicum tree has traditionally been termed true cinnamon / Ceylon cinnamon in recognition of this indigenous Sri Lankan plant being the source of the worlds finest cinnamon. This is in contrast to cassia, which is grown in China, Indonesia and Vietnam and which gives a lower quality alternative which also contains the toxic substance coumarin â?? which is not found in Ceylon cinnamon. Cinnamon is sold in many grades. The highest grade is sold in the form of Quills, which are several peels joined together by overlaps, the hollow of which has been filled with small pieces of the same peel. Quills are sold in four different grades (Alba, Continental, Mexican and Hamburg) depending on the diameter of the rolled quills.