foglie

Foglie are the leaves of plants. They are usually flat, green, and serve as the primary site of photosynthesis, as well as gas exchange and water regulation. Most leaves attach to the stem by a petiole, though some species have sessile leaves directly on the stem. The term foglia is Italian for leaf.

In terms of structure, the blade or lamina is the broad, thin portion of the leaf, while the base attaches toward the stem and the apex points outward. A central vein called the midrib runs through the blade with a network of secondary veins. The epidermis is coated by a waxy cuticle, and stomata on the underside regulate gas exchange. Chloroplasts within mesophyll cells carry out photosynthesis.

Leaves are classified by architecture and venation. They can be simple, with a single blade, or compound, with multiple leaflets on a rachis. Compound leaves include pinnate forms (leaflets along a central axis), palmate forms (leaflets radiating from a common point), and bipinnate forms. Vein patterns include pinnate and reticulate venation, and margins may be entire, serrate, or lobed.

Leaf arrangement on the stem varies as alternate, opposite, or whorled. Leaves also show a range of shapes and sizes and possess adaptations to light, temperature, and water availability, such as sun leaves versus shade leaves and, in some plants, thicker cuticles or reduced surface area.

Ecologically, many temperate trees shed their leaves seasonally (deciduous), while others retain them year-round (evergreen). Humans rely on leaves for food and flavoring (salads, herbs, tea) and for medicinal and cultural uses. The word foglia ultimately derives from Latin folium, meaning leaf.