Both members of the laurel family, cinnamon (cinnamomum verum) and cassia (cinnamomum aromaticum) are combined into what we Americans recognize as cinnamon. The actual flavors are similar but are easily dis- tinguishable when tasted side by side.
The spices come from the bark of Asian evergreen trees, harvested with much skill and tradition from trees 25 years or older. When the trees are still moist from seasonal rains, the inner bark is carefully stripped with special tools using techniques that have been passed down through many generations.
Cassia bark is much stronger than true cinnamon. In stick form, it’s thicker and almost impossible to grind. True cinnamon bark is much finer and crumbles easily in the hand. The buds and leaves are used in several Asian dishes and make delightful aromatic additions to candies, liqueurs, and potpourri. Cinnamon is a crucial element in many spice blends, including curries, barbecue rub, jerk rub, mulling spice, mole, and of course, pumpkin pie spice.
Both cinnamon and cassia are readily available. Sticks sold whole in markets and specialty shops are usually clearly labeled as one or the other. If you happen across a bin of unmarked sticks in an ethnic market, remember that the hard ones are cassia and the brittle ones are cinnamon.