A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants.
Typically a leaf is a thin, flattened organ borne above ground and specialized for photosynthesis, but many types of leaves are adapted in ways almost unrecognisable in those terms: some are not flat (for example many succulent leaves and conifers), some are not above ground (such as bulb scales), and some are without major photosynthetic function (consider for example cataphylls, spines, and cotyledons).
Conversely, many structures of non-vascular plants, or even of some lichens, which are not plants at all (in the sense of being members of the kingdom Plantae), do look and function much like leaves. Furthermore, several structures found in vascular plants look like leaves but are not actually leaves; they differ from leaves in their structures and origins. Examples include phyllodes, cladodes, and phylloclades.
Read more about Leaf: General Nature of Leaves, Large-scale Features (leaf Morphology), Seasonal Leaf Loss, Morphology, Adaptations, Interactions With Other Organisms, Bibliography, See Also
Famous quotes containing the word leaf:
“With fairest flowers
Whilst summer lasts and I live here, Fidele,
I’ll sweeten thy sad grave. Thou shalt not lack
The flower that’s like thy face, pale primrose, nor
The azured harebell, like thy veins; no, nor
The leaf of eglantine, whom not to slander,
Outsweetened not thy breath.”
—William Shakespeare (1564–1616)
“Once they came on a maple in a glade,
Standing alone with smooth arms lifted up,
And every leaf of foliage she’d worn
Laid scarlet and pale pink about her feet.”
—Robert Frost (1874–1963)
“Black creeps from root to root,
each leaf
cuts another leaf on the grass,
shadow seeks shadow,
then both leaf
and leaf-shadow are lost.”
—Hilda Doolittle (1886–1961)