Rutgers Gardens, New Brunswick, NJ - USA

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.

Hosta (pron.: /ˈhɒstə/, syn. Funkia) is a genus of about 23–45 species of plants commonly known as hostas, plantain lilies (particularly in Britain) and occasionally by the Japanese name giboshi. Hostas are widely cultivated as shade-tolerant foliage plants. The genus is currently placed in the family Asparagaceae, subfamily Agavoideae, and is native to northeast Asia. Like many "lilioid monocots", the genus was once classified in the Liliaceae. The name Hosta is in honor of the Austrian botanist Nicholas Thomas Host. The rejected generic name Funkia, also used as a common name, can be found in some older literature.

Vascular plants (from Latin vasculum: duct), also known as tracheophytes (from the equivalent Greek term trachea) and also higher plants, form a large group of plants that are defined as those land plants that have lignified tissues (the xylem) for conducting water and minerals throughout the plant. They also have (non-lignified) tissue to conduct products of photosynthesis. Vascular plants include the clubmosses, horsetails, ferns, gymnosperms (including conifers) and angiosperms (flowering plants). Scientific names for the group include Tracheophyta and Tracheobionta.

This is a partial list of garden plants, plants that can be cultivated in the garden, listed alphabetically by genus. See also list of plants by common name.

In botany, leaf shape is characterised with the following terms (botanical Latin terms in brackets):

Agavoideae is a subfamily of monocot flowering plants in the family Asparagaceae, order Asparagales. It has previously been treated as a separate family, Agavaceae. The group includes many well-known desert and dry zone types such as the agave, yucca, and Joshua tree. There are about 640 species in around 23 genera, widespread in the tropical, subtropical and warm temperate regions of the world.