From The Food Encyclopedia by Jacques Rolland and Carol Sherman
The young shoots of an edible species of bamboo plant, Phyllostachys, which originated in the tropical regions of Asia and has been consumed there for thousands of years. The leaves are edible, as well as the heart and the sugary sap, which is extracted by slicing the skin of the plant. The shoots are harvested as soon as they emerge from the ground. They're ivory in color because they're grown without light and are kept covered to avoid the production of chlorophyll, which would turn them green. Although many species of bamboo have edible shoots, they shouldn't be eaten raw. They contain toxins, which are destroyed by the cooking process or even a slight blanching. Winter bamboo shoots are considered more desirable because they are more tender and less fibrous.
