leaf: growth leaf: external leaf: internal leaf: modified
Leaves / modified
Like other organs, leaves are often modified for functions other than photosynthesis. Below are a few examples:
Tendrils-of plants are leaves modified for support. In some plants the entire leaf is a tendril; photosynthesis in these plants is delegated to leaflike structures called stipules at the base of each leaf. Tendrils, of many plants may be up to 30 cm long, which makes them well suited for seeking support in the plant's nearby environment.
Stipules-are small, leaflike structures at the base of petioles, and have a variety of functions. Some are photosynthetic, while others form protective spines. see the rose below for an illustration
Spines-leaves modified for protection. Note the sharp spines on the cactus above
Bud Scales-are tough, overlapping, waterproof leaves that protect buds from frost, desiccation, and pathogens. Bud scales form before the onset of unfavorable growing seasons i.e. winter.
Window leaves-are common in many desert plants, are shaped like tin ice-cream cones and grow mostly underground, with only a small transparent "window" tip protruding above the soil level.
Bracts are floral leaves that form at the base of a flower or flower stalk. They are usually small and scalelike, and protect developing flowers.
Storage leaves-flowerpot leaves are typically of rosette plants, and such epiphytes. They are packed tightly into a flower potlike structure that catches falling water and debris.
Other such leaves may expand to hold water in dry environments
Insect-trapping leaves-in carnivorous plants, leaves modified for attracting, trapping, and digesting animals. These adaptations range from sticky flypaper surfaces to vatlike leaves.
Leaves modified for reproduction-form tiny plants at the edges of their leaves. These plants become new individuals when they are shed from parent leaves.
Cotyledons-are embryonic leaves. Monocots, usually have one cotyledon, while dicots have two.
Prophylls-are the first leaves to form on axillary buds. Monocots have one usually, where dicots have two, suggesting that tiny leaves may be analogous to cotyledons. Prophylls protect axillary buds.