Botanists view the region ranging from central China to the Himalayas to the northern part of South Asia as a key area for research into the origin of flowering plants. Native plant species in Asia are numerous; botanists also study Asian plants that are relics of ancient times, from millions of years ago, as well as fossils.
Ancient species include such gymnosperms as the dawn redwood of central China. Dawn redwood is similar to California's redwood and giant sequoia. Another fossil-like tree is East Asia's ginkgo. This species not only has great ornamental value but also has great commercial value as an alternative medicine. Ginkgo trees are also dustresistant, which makes them a favorite in urban landscaping and the ornamental industry. Other Asian plants such as the magnolia and its allied families may represent the most primitive flowering plants.
Introduced Plants
Asian flora today also includes introduced plant species from other parts of the world that play important roles in people's lives. For example, the rubber tree of South America is cultivated in tropical Asia. This tree produces raw material for the natural rubber industry, in which Asia is the largest producer in the world. Cacao, a tree species that provides the basis of chocolate, was introduced from tropical America. Corn, one of the most common crops in Asia, was introduced from America several thousand years ago. Several vegetables, including the tomato, potato, eggplant, green pepper, hot pepper, and chili (all from the nightshade family), were introduced to Asia long ago. Peanuts, originally from Brazil, are also cultivated in Asia.
Coffee, an increasingly popular beverage in Asia, came originally from Africa. An introduced fruit is the pineapple, which came from tropical America but now is popular in tropical Asia. The sweet potato, from Central America, is also cultivated in Asia. Tobacco is another crop introduced to and cultivated in Asia. It originally came from tropical America, but its yield in China has made that nation a leading producer.
Impact of Human Activity
Asia's highly diversified flora has contributed positively to the daily lives of people around the world, but the demands of a rapidly growing population are a constant threat. Deforestation, overgrazing, and urbanization have become major reasons for heavy losses of Asian flora, especially in South and East Asia. In China alone, eight key plant species were added to the first-class protection list in the Red Book of 1992 (equivalent to the U.S. endangered species list). Among them are the Chinese silver fir, dawn redwood, and ginseng. These plants only grow in several isolated locations and are rare in their original range. As natural vegetation is cut for farming, grazing, or simply for cooking and heating fuel, fewer plants remain. Although scientists from around the world have worked on this problem for decades, the situation has not improved.
See also: Tropical Rain, Desert and Steppe, Taiga and Tundra, Food Crops
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