The third-richest region, tropical rain / dry forests, is found in South Asia, which reaches from the Philippines in the east to Pakistan in the west, and from the Himalayas in the north to Thailand in the south. Twenty five thousand to thirty thousand species of plants grow there. This region has both tropical rain forests and tropical seasonal dry forests. The tropical rain forest is mainly found in the region's lowlands and the seasonal dry forests in the highlands or mountainous areas. More often, these two types of forests are combined.
The tropical seasonal dry forests usually grow in a climate with wet and dry seasons or under a somewhat cooler climate than the tropical rain forests. The canopy, formed from primarily deciduous broad leafed species, is much thinner than the canopy in the tropical rain forest, so more sunlight reaches plants below. Many different plant species live together, forming tropical jungles. Tall, thick-trunked trees, colorful orchids, ferns, dense mosses, and twined vines and lianas dominate this vast region. The major components of these kinds of forests are members of the dipterocarpas, sweetsop, laurel, piper, fig, dissotis, akee, gardenia, periwinkle, milkweed, African violet, palm, and aroid families. In central and southern India and in some areas of Pakistan there are tropical grasslands, called the savanna. Because of the savanna's hot, dry weather, mainly coarse grasses grow there.
See also: Desert and Steppe, Taiga and Tundra, Food Crops, Scientific Value
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