Food produced by photosynthesis in the leaves flows down the stems to the roots and fruits, while water and nutrients taken by the roots travel up the stems to other sections of the plant. The edible stems are all celery, asparagus, bamboo shoots, rhubarb, and sugar cane. Other plant stems, such as broccoli and cauliflower, are also edible. Granulated sugar is made from sugar cane and sugar beet aboveground stems. The trunks of maple trees are used to make maple sugar. Cinnamon is derived from the bark of the Cinnamomum genus of trees. Potatoes are edible.