Different leaf names include ovate, cordate, oblanceolate, petiolated, sessile, simple, compound, entire, sinuate, dentate, serrate, lobed, elliptic, lanceolate, acicular, hastate, linear, parallel-veined, pinnate and palmate. Leaf names generally are associated with the shape, arrangement on the stem or other defining characteristics.
The shape of a leaf will allude to what kind of environment the plant is located in. Leaves are used to gather sunlight and carbon dioxide for photosynthesis while also helping it to retain water and, in some cases, to cool the plant off.
The different contusions, whorls, edges and lobes on some leaves are usually indicative of a higher canopy living environment. The greater surface area supplied by the irregular shape of these leaves allows for the plant to expel heat from the direct sunlight much faster. This keeps the leaves and, in turn the plant from overheating and allows it to retain water more efficiently.
A leaf that is large and fleshy with smooth edges to it will most likely be located closer to the ground and away from the sunlight. Because of its location, the leaf is able to retain water more efficiently without having to combat overheating from direct sunlight and therefore does not require the extra surface area of an irregular shape. In addition, a leaf closer to the ground needs to maximize its area of coverage in order to insure that it gets the appropriate amount of sunlight which accounts for the bigger overall size of the leaf.