Chengdu has 12 rivers such as Ming River and Tuo River, together with numerous tributaries. Apart from the reputed Dujiangyan Irrigation System, reservoirs, pools and weirs crisscross in the city, with an effective irrigating area of 366,000 hectares. It is roughly estimated that there are 11 classes, 200 families, 764 genera and 3000 kinds of animals and plants, in which 2682 are main plants and 237 main animals. Precious plants are gingko tree, dove tree, michelia wilsonii and henryi; national protected endangered animals include panda, red panda, golden monkey and gnu. There are more than 860 Chinese medical herbs, in which hemlock parsley, curcumae, Fructus Mume and Rhizoma Coptidis are renowned worldwide. Chengdu is rich in mineral resources, proven metal minerals include iron, titanium, vanadium,copper, lead, zincum, aluminium, gold, silver, strontium and REE. There are more than 60 Non-ferrous metals, including glaucocerinite, picrolite, gypsum, calcite,limestone, marble, shale, gravel, coal and natural gas.