A major organ of plants, providing the site for photosynthesis .
Leaves are very diverse in their shape and form and in their arrangement on the plant stem.
The increased surface area of leaves also allows for transpiration . The 'leaves' of mosses are not homologous with the leaves of higher plants. Leaves may be modified into a variety of specialized structures, such as the traps of insectivorous plants, or reduced to spines, as in cacti. The New Penguin Dictionary of Science 2. The New Penguin Dictionary of Science 5.