Most leaves function as photosynthetic organs, but some leaves serve specialized functions that enable a plant to survive in a particular environment. The photosynthetic capabilities of specialized leaves may be reduced or enhanced depending on the role they serve.

      Cataphylls (bud scales) are modified leaves that cover and protect young vegetative or reproductive shoots. Cataphylls are often leathery or have a soft insulated lining that protects the bud over harsh winters. Many bud scales exude sticky substances that help keep the bud watertight and protect it from insect damage. It was once thought that bud scales were leaves whose growth was arrested at the end of the growing season. However, many bud scales have developmental patterns that are quite different from those of typical foliage leaves. The number and morphology of bud scales varies greatly between plants and these differences can be used for identification purposes.

      Some plants, such as Pisum, have highly modified leaf tendrils. Leaves, particularly the upper leaf regions (petiole and lamina), may be modified into twining structures similar to the shoot tendrils of climbing plants. The hook tendrils found on Cissus vines provide an excellent example of this modification. These tendrils often mature into thick woody structures. Another good example of modified leaf tendrils is the adhesive disc tendril of Parthenocissus discussed in the section on vining plants. The leaves of Clematis provide examples of petioles modified as tendrils. These petioles elongate greatly to twine around fences and trellises.

      Window leaves allow some plants to survive in arid desert environments. Both Haworthia and Lithops are succulent plants that incorporate these transparent surfaces that direct light to their interiors. The stone plant, Lithops, has its succulent leaves mostly buried below ground and thus protected from desiccation. The leaf surfaces exposed to sunlight direct the light to leaf tissues below ground that contain chloroplasts.

      Some epiphytic ferns, such as the staghorn fern, have leaves modified to clasp onto other plants or substrates and prevent them from falling. These epiphytic ferns are frequently found in the rainforest. Clasping leaves hold the plant to its substrate high in the canopy where it can successfully compete for sunlight and water.