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Aristate leaves end in a stiff point that may continue the primary leaf vein; this can resemble the stem end of a phylloclade/cladode. Epiphylly: flowers and fruit develop "on a leaf". A stem and a leaf are merged with one another. [7] Examples include Monophyllaea in family Gesneriaceae and Helwingia in Helwingiaceae.
A leaf (pl.: leaves) is a principal appendage of the stem of a vascular plant, [1] usually borne laterally above ground and specialized for photosynthesis.Leaves are collectively called foliage, as in "autumn foliage", [2] [3] while the leaves, stem, flower, and fruit collectively form the shoot system. [4]
Leaves may also be whorled if several leaves arise, or appear to arise, from the same level (at the same node) on a stem. Veronicastrum virginicum has whorls of leaves separated by long internodes. With an opposite leaf arrangement, two leaves arise from the stem at the same level (at the same node), on opposite sides of the stem. An opposite ...
Plants that have an underground storage organ are called geophytes in the Raunkiær plant life-form classification system. [ 2 ] [ 3 ] Storage organs often, but not always, act as perennating organs which enable plants to survive adverse conditions (such as cold, excessive heat, lack of light or drought).
Most plants have an epidermis that is a single cell layer thick. Some plants like Ficus elastica and Peperomia, which have a periclinal cellular division within the protoderm of the leaves, have an epidermis with multiple cell layers. Epidermal cells are tightly linked to each other and provide mechanical strength and protection to the plant.
The illustration (to the right) of Acacia suaveolens from Novae Hollandiae plantarum specimen shows the juvenile true leaves, together with the developing phyllodes, and the phyllodes of the mature plant. The genus, Daviesia, in the family Fabaceae, is characterised in part by the plants having phyllodes. [2] Phyllodes in Fabaceae
Palisade cells contain a high concentration of chloroplasts, particularly in the upper portion of the cell, making them the primary site of photosynthesis in the leaves of plants that contain them. Their vacuole also aids in this function: it is large and central, pushing the chloroplasts to the edge of the cell, maximising the absorption of ...
Suberin is a lipophilic, complex polyester biopolymer of plants, composed of long-chain fatty acids called suberin acids and glycerol. Suberin, interconnected with cutins and lignins, also complex macromolecules, form a protective barrier in the epidermal and peridermal cell walls of higher plants. Suberins and lignins are considered covalently ...