The climate in India ranges from mountain in the Himalayas to a variety of other climates ranging from desert, monsoonal and rain forest.
Part of the reason for the variety in natural vegetation is the topography and rainfall. The soil types, amount of sunlight, rainfall and temperature varieties all contribute to the variety of flora that can be found on the sub-continent of India.
The vegetation zones in India are as follows: tropical rain forests, tropical deciduous forests or (monsoon forests) found in the state of Kerala in India, moist deciduous forests found in the Western Ghats, thorn forests and shrubs extend towards northern Madhya Pradesh (primarily Malwa Plateau) and south-west Uttar Pradesh, covering Bundelkhand plateau, tidal forests found along the coasts and rivers, alpine and tundra vegetation at altitudes above 3600 meter, and the Himalayan vegetation, and desert region such as the Thar Desert. (http://www.indianetzone.com/40/natural_vegetation_india.htm)
Vegetation in India includes almost every plant family in the world. This is because of a very wide range of land and climatic condition that exist in India.
In India, you can find one of the highest mountain ranges of Himalaya, as well as low lying lands in Rann of Kutch often flooded by sea water. You can find Thar desert in the West as well as one of the worlds largest alluvial plain in Northern India just South of Himalaya. Also you can find World's one of the rainiest parts in India.
The Deccan Plateau with its dry and hot environment offers another kind of climate. Large parts of land in Gujarat and Maharashtra region of Western India are covered with thick layer of soil formed by volcanic ash that provides conditions suitable for still other kinds of vegetation. Similarly, on the Eastern side the marshy land of Sundarban delta formed by river Ganges and Brahmputra are also home for very different kinds of vegetation.
The Himalaya range of mountains have different kinds of vegetation at different heights. In addition, there are other mountain ranges of different heights and in different region that are home to very different kind of vegetation. Western Ghats on the West side of Deccan plateau have height of about 1500 meters while Eastern Ghats on the eastern side have height of 600 meters. Vindhyachal mountain Range which divides North and South India has a height of 1200 meters. Aravali Range in the Western part of North India is next to the Thar desert.
Also India has a long Coastline flanking the Deccan plateau on East and West, and Broad strips of plains run along these coastlines. India also has many small islands including the Lakshwadeep, Andman and Nicobar group of islands.