A leaf (plural: leaves) is an essential part of a vascular plant’s stem, typically growing laterally above ground and specialized for photosynthesis. Together, leaves are known as foliage, which includes the leaves, stem, flower, and fruit forming the shoot system.
The primary photosynthetic tissue in most leaves is the palisade mesophyll, found mainly on the upper side of the leaf blade. In some species, like Eucalyptus, this tissue can be present on both sides, making the leaves isobilateral. Leaves usually have distinct upper and lower surfaces that differ in color, texture, and stomata count.
Leaves are mostly green due to chlorophyll, which absorbs sunlight for photosynthesis. Leaves with lighter or white patches are referred to as variegated leaves.
