Bamboos are woody, perennial evergreen plants that are members of the true grass family. There are about 1,200 species worldwide occurring in diverse climates from cold, 12,000-foot mountains to low, hot, tropical regions. They occur naturally on all continents except for Europe. Bamboo stems, called culms, can range in height from a few centimeters to 40 meters (131 feet), with stem diameters ranging from 1 millimeter to 30 centimeters (about 12 inches).