In botany, a leaf is an above-ground plant organ specialized for photosynthesis. For this purpose, a leaf is typically flat (laminar) and thin, to expose the chloroplast containing cells (chlorenchyma tissue) to light over a broad area, and to allow light to penetrate fully into the tissues. Leaves are also the sites in most plants where respiration, transpiration, and guttation take place. Leaves can store food and water, and are modified in some plants for other purposes. The comparable structures of ferns are correctly referred to as fronds. Botany is the scientific study of plant life. ... Divisions Land plants (embryophytes) Non-vascular plants (bryophytes) Marchantiophyta - liverworts Anthocerotophyta - hornworts Bryophyta - mosses Vascular plants (tracheophytes) Lycopodiophyta - clubmosses Equisetophyta - horsetails Pteridophyta - true ferns Psilotophyta - whisk ferns Ophioglossophyta - adderstongues Seed plants (spermatophytes) †Pteridospermatophyta - seed ferns Pinophyta - conifers Cycadophyta - cycads Ginkgophyta - ginkgo Gnetophyta - gnetae Magnoliophyta - flowering plants Adiantum pedatum (a... In biology, an organ (Latin: organum, instrument, tool) is a group of tissues, which perform a specific function or group of functions. ... Leaf. ... The inside of a chloroplast The inside of a chloroplast Chloroplasts are organelles found in plant cells and eukaryotic algae which conduct photosynthesis. ... Respiration is the process of exchanging oxygen and carbon dioxide between an organism and its external environment (breathing). ... Transpiration is a continuous process caused by the evaporation of water from leaves of plants and its corresponding uptake from roots in the soil. ... Guttation is the appearance of drops of water on the leaves of some vascular plants, such as grasses. ... Water (from the Old English word wæter; c. ... Classes Marattiopsida Osmundopsida Gleicheniopsida Pteridopsida A fern, or pteridophyte, is any one of a group of some twenty thousand species of plants classified in the Division Pteridophyta, formerly known as Filicophyta. ... A fern with simple (lobed or pinnatifid) blades, the dissection of each blade not quite reaching to the rachis. ...

A leaf with laminar structure and pinnate venation

Fallen leaf of a maple. Note areas where chlorophyll (green) has been destroyed now appear yellow.

Fallen autumn leaves

Download high resolution version (1024x768, 158 KB)From http://pdphoto. ... Download high resolution version (1024x768, 158 KB)From http://pdphoto. ... Picture of a fallen leaf for the leaf article File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Picture of a fallen leaf for the leaf article File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links Download high resolution version (1600x1067, 349 KB) Please see the file description page for further information. ... Image File history File links Download high resolution version (1600x1067, 349 KB) Please see the file description page for further information. ...

Leaf anatomy

A structurally complete leaf of an angiosperm consists of a petiole (leaf stem), a lamina (leaf blade), and stipules (small processes located to either side of the base of the petiole). The point at which the petiole attaches to the stem is called the leaf axil. Not every species produces leaves with all of these structural parts. In some species, paired stipules are not obvious or are absent altogether; a petiole may be absent; or the blade may not be laminar (flattened). The tremendous variety shown in leaf structure (anatomy) from species to species is presented in detail below under Leaf types, arrangements, and forms. Classes Magnoliopsida - Dicots Liliopsida - Monocots The flowering plants (also called angiosperms) are a major group of land plants. ... The lanceolate-linear, paired stipules of Hibiscus kokio In botany, stipule refers to outgrowths borne on either side of the base of a leafstalk (or petiole). ...

A leaf is considered to be a plant organ, typically consisting of the following tissues:

1. An epidermis that covers the upper and lower surfaces
2. An interior chlorenchyma called the mesophyll
3. An arrangement of veins (the vascular tissue).

Image File history File links Leaf_anatomy. ...

Epidermis

The epidermis is the outer multi-layered group of cells covering the leaf. It forms the boundary between the plant and the external world. The epidermis serves several functions: protection against water loss, regulation of gas exchange, secretion of metabolic compounds, and (in some species) absorption of water. Most leaves show dorsoventral anatomy: the upper (adaxial) and lower (abaxial) surfaces have somewhat different construction and may serve different functions. The epidermis is the outer multi-layered group of cells covering the leaf and young tissues of a plant. ...

The epidermis is usually transparent (epidermal cells lack chloroplasts) and coated on the outer side with a waxy cuticle that prevents water loss. The cuticle may be thinner on the lower epidermis than on the upper epidermis; and is thicker on leaves from dry climates as compared with those from wet climates. This article needs to be cleaned up to conform to a higher standard of quality. ... In botany the cuticle is the waxy covering produced by the epidermal cells of leaves to protect the plant from excessive water loss. ...

The epidermis tissue includes several differentiated cell types: epidermal cells, guard cells, subsidiary cells, and epidermal hairs (trichomes). The epidermal cells are the most numerous, largest, and least specialized. These are typically more elongated in the leaves of monocots than in those of dicots. Orders Base Monocots: Acorus Alismatales Asparagales Dioscoreales Liliales Pandanales Family Petrosaviaceae Commelinids: Arecales Commelinales Poales Zingiberales Family Dasypogonaceae Monocotyledons or monocots are a group of flowering plants usually ranked as a class and once called the Monocotyledoneae. ... Orders see text Dicotyledons or dicots are flowering plants whose seed contains two embryonic leaves or cotyledons. ...

The epidermis is covered with pores called stomata (sing., stoma), part of a stoma complex consisting of a pore surrounded on each side by chloroplast-containing guard cells, and two to four subsidiary cells that lack chloroplasts. The stoma complex regulates the exchange of gases and water vapor between the outside air and the interior of the leaf. Typically, the stomata are more numerous over the abaxial (lower) epidermis than the (adaxial) upper epidermis. A pore, in general, is some form of opening, usually very small. ... This is not about surgically created bowel openings; see stoma (medicine) In botany, a stoma (also stomate; plural stomata) is a tiny opening or pore, found mostly on the undersurface of a plant leaf, and used for gas exchange. ...

Trichomes or hairs grow out from the epidermis in many species. Interior structure of a trichome. ...

Mesophyll

Most of the interior of the leaf between the upper and lower layers of epidermis is a parenchyma (ground tissue) or chlorenchyma tissue called the mesophyll (= middle leaf). This "assimilation tissue" is the primary location of photosynthesis in the plant. The products of photosynthesis are called assimilates. The parenchyma are the functional parts of an organ in the body (i. ... Chlorenchyma cells in plant anatomy are parenchyma cells that contain chloroplasts. ... This article is about the leaf, a plant organ. ...

In ferns and most flowering plants the mesophyll is divided into two layers:

• An upper palisade layer of tightly packed, vertically elongated cells, one to two cells thick, directly beneath the adaxial epidermis. Its cells contain many more chloroplasts than the spongy layer. These long cylindrical cells are regularly arranged in one to five rows. Cylindrical cells, with the chloroplasts close to the walls of the cell, can take optimal advantage of light. The slight separation of the cells provides maximum absorption of carbon dioxide. This separation must be minimal to afford capillary action for water distribution. In order to adapt to their different environment (such as sun or shade), plants had to adapt this structure to obtain optimal result. Sun leaves have a multi-layered palisade layer, while shade leaves or older leaves closer to the soil, are single-layered.
• Beneath the palisade layer is the spongy layer. The cells of the spongy layer are more rounded and not so tightly packed. There are large intercellular air spaces. These cells contain less chloroplasts than those of the palisade layer.

The pores or stomata of the epidermis open into substomatal chambers, connecting to air spaces between the spongy layer cells. Palisade cells can be found inside the leaf of a green plant. ... Absorption has a number of meanings: In physics, absorption is a process in which particles of some sort encounter another material and are taken up by or even disappear in it. ... Capillary action or capillarity (also known as capillary motion) is the ability of a narrow tube to draw a liquid upwards against the force of gravity. ...

These two different layers of the mesophyll are absent in many aquatic and marsh plants. Even an epidermis and a mesophyll may be lacking. Instead for their gaseous exchanges they use a homogenous aerenchyma (thin-walled cells separated by large gas-filled spaces). Their stomata are situated at the upper surface.

Leaves are normally green in color, which comes from chlorophyll found in plastids in the chlorenchyma cells. Plants that lack chlorophyll cannot photosynthesize. Look up green in Wiktionary, the free dictionary. ... Chlorophyll is a green photosynthetic pigment found in plants, algae, and cyanobacteria. ... Plastids are major organelles found only in plants and algae. ...

Leaves in temperate, boreal, and seasonally dry zones may be seasonally deciduous (falling off or dying for the inclement season). This mechanism to shed leaves is called abscission. After the leaf is shed, a leaf scar develops on the twig. In cold autumns they sometimes turn yellow, bright orange or red as various accessory pigments (carotenoids and anthocyanins) are revealed when the tree responds to cold and reduced sunlight by curtailing chlorophyll production. In geography, temperate latitudes of the globe lie between the tropics and the polar circles. ... Boreal means northern from the eponymous Boreas, god of the North Wind in Greek mythology. ... Deciduous means temporary or tending to fall off (deriving from the Latin word decidere, to fall off). ... Abscission (from ab- away from, and scission cutting or severing) is the shedding of a body part. ... Yellow is a color with a wavelength 565-590 nanometers. ... The colour orange occurs between red and yellow in the visible spectrum at a wavelength of about 620–585 nanometres. ... Red is a color at the lowest frequencies of light discernible by the human eye. ... Carotenoids are organic pigments naturally occurring in plants and some other photosynthetic organisms like algae, some types of fungus and some bacteria. ... Plants with abnormally high anthocyanin quantities are popular as ornamental plants - here, a selected purple-leaf cultivar of European Beech Anthocyanin (Etymology: greek. ... Prism splitting light Sunlight in the broad sense is the total spectrum of electromagnetic radiation given off by the Sun. ...

Veins

The veins are the vascular tissue of the leaf and are located in the spongy layer of the mesophyll. They are typical examples of pattern formation through ramification. Cross section of celery stalk, showing vascular bundles, which include both phloem and xylem. ...

The veins are made up of:

• xylem, which brings water from the stem into the leaf.
• phloem, which usually moves sap out, the latter containing the glucose produced by photosynthesis in the leaf.

The xylem typically lies over the phloem. Both are embedded in a dense parenchyma tissue (= ground tissue), called pith, with usually some structural collenchyma tissue present. Tracheids and vessel elements In vascular plants, the xylem is the tissue that carries water up the root and stem. ... In vascular plants, phloem is the tissue that carries organic nutrients, particularly sucrose to all parts of the plant where needed. ...

Leaf morphology

External leaf characteristics (such as shape, margin, hairs, etc.) are important for identifying plant species, and botanists have developed a rich terminology for describing leaf characteristics.

The leaves on this plant are arranged in pairs opposite one another, with successive pairs at right angles to each other ("decussate") along the red stem. Note developing buds in the axils of these leaves.

Leaves may be classified in many different ways, and the type is usually characteristic of a species, although some species produce more than one type of leaf. The terminology associated with describing leaf morphology is presented (with illustrations) at Wikibooks. Download high resolution version (950x683, 185 KB)Photo of plant (Alternanthera sp. ... Download high resolution version (950x683, 185 KB)Photo of plant (Alternanthera sp. ...

Basic leaf types

• Ferns have fronds.
• Conifer leaves are typically needle-, awl-, or scale-shaped
• Angiosperm (flowering plant) leaves: the standard form includes stipules, petiole, and lamina.
• Microphyll leaves.
• Sheath leaves (type found in most grasses).
• Other specialized leaves.

Classes Marattiopsida Osmundopsida Gleicheniopsida Pteridopsida A fern, or pteridophyte, is any one of a group of some twenty thousand species of plants classified in the Division Pteridophyta, formerly known as Filicophyta. ... Orders & Families Cordaitales † Pinales   Pinaceae - Pine family   Araucariaceae - Araucaria family   Podocarpaceae - Yellow-wood family   Sciadopityaceae - Umbrella-pine family   Cupressaceae - Cypress family   Cephalotaxaceae - Plum-yew family   Taxaceae - Yew family Vojnovskyales † Voltziales † The conifers, division Pinophyta, are one of 13 or 14 division level taxa within the Kingdom Plantae. ... Classes Magnoliopsida - Dicots Liliopsida - Monocots The flowering plants (also called angiosperms) are a major group of land plants. ... Microphylls are photosynthetic flaps of plant tissue with a solitary, unbranched vein. ... The word sheath has a number of related meanings in English. ... Subfamilies There are 7 subfamilies: Subfamily Arundinoideae Subfamily Bambusoideae Subfamily Centothecoideae Subfamily Chloridoideae Subfamily Panicoideae Subfamily Pooideae Subfamily Stipoideae The true grasses are monocotyledonous plants (Class Liliopsida) in the Family Poaceae, also known as Gramineae. ...

Arrangement on the stem

As a stem grows, leaves tend to appear arranged around the stem in away that optimizes yield of light. In essence, leaves come off the stem in a spiral pattern, either clockwise or counterclockwise, with (depending upon the species) the same angle of divergence. There is a regularity in these angles and they follow the numbers in a Fibonacci series: 1/2, 2/3, 3/5, 5/8, 8/13, 13/21, 21/34, 34/55, 55/89. This series tends to a limit of 360° x 34/89 = 137,52 or 137° 30', an angle known mathematically as the 'golden angle'. In the series, the numerator gives the number of complete turns or gyres until the leaf arrives at the initial position. The denominator gives the number of leaves in the arrangement. This can be demonstrated by the following: In mathematics, the Fibonacci numbers form a sequence defined recursively by: In words: you start with 0 and 1, and then produce the next Fibonacci number by adding the two previous Fibonacci numbers. ...

• alternate leaves have an angle of 180° (or 1/2)
• 120° (or 1/3) : three leaves in one circle
• 144° (or 2/5) : five leaves in two gyres
• 135° (or 3/8) : eight leaves in three gyres.

The fact that an arrangement of anything in nature can be described by a mathematical formula is not in itself mysterious. Mathematics is the science of discovering numerical relationships and applying formulae to these relationships. The formulae themselves can provide clues to the underlying physiological processes that, in this case, determine where the next leaf bud will form in the elongating stem. However, we can more easily describe the arrangement of leaves using the following terms:

• Alternate — leaf attachments singular at nodes, and leaves alternate direction, to a greater or lesser degree, along the stem.
• Opposite — leaf attachments paired at each node; decussate if, as typical, each successive pair is rotated 90° going along the stem; or distichous if not rotated, but two-ranked (in the same plane).
• Whorled — three or more leaves attach at each point or node on the stem. As with opposite leaves, successive whorls may or may not be decussate, rotated by half the angle between the leaves in the whorl (i.e., successive whorls of three rotated 60°, whorls of four rotated 45°, etc). Note: opposite leaves may appear whorled near the tip of the stem.
• Rosulate — leaves form a rosette ( = a cluster of leaves growing in crowded circles from a common center).

Leaves of the Norway Spruce (Picea abies) are needle-shaped and the arrangement is spiral

Closeup shot of a stem of needles (perhaps Norway spruce?) by USFWS and obtained from the GIMP photo library. ... Closeup shot of a stem of needles (perhaps Norway spruce?) by USFWS and obtained from the GIMP photo library. ...

Divisions of the lamina (blade)

Two basic forms of leaves can be described considering the way the blade is divided. A simple leaf has an undivided blade. However, the leaf shape may be one of lobes, but the gaps between lobes do not reach to the main vein. A compound leaf has a fully subdivided blade, each leaflet of the blade separated along a main or secondary vein. Because each leaflet can appear to be a "simple leaf", it is important to recognize where the petiole occurs to identify a compound leaf. Compound leaves are a characteristic of some families of higher plants, such as the Fabaceae. Subfamilies Faboideae Caesalpinioideae Mimosoideae References GRIN-CA 2002-09-01 The name Fabaceae belongs to either of two families, depending on viewpoint. ...

• Palmately compound leaves have the leaflets radiating from the end of the petiole, like fingers off the palm of a hand. There is no rachis, e.g. Cannabis (hemp) and Aesculus (buckeyes).
• Pinnately compound leaves have the leaflets arranged along the main or mid-vein (called a rachis in this case).
  • odd pinnate: with a terminal leaflet, e.g. Fraxinus (ash).
  • even pinnate: lacking a terminal leaflet, e.g. Swietenia (mahogany).
• Bipinnately compound leaves are twice divided: the leaflets are arranged along a secondary vein that is one of several branching off the rachis. Each leaflet is called a pinnule. The pinnules on one secondary vein are called pinna; e.g. Albizia (silk tree).
• trifoliate: a pinnate leaf with just three leaflets, e.g. Trifolium (clover), Laburnum (laburnum).
• pinnatifid: pinnately dissected to the midrib, but with the leaflets not entirely separate, e.g. some Sorbus (whitebeams).

Characteristics of the petiole

• Petiolated leaves have a petiole.
  • In peltate leaves, the petiole attaches to the blade inside from the blade margin.
• Sessile or clasping leaves do not have a petiole. In sessile leaves the blade attaches directly to the stem. In clasping leaves, the blade partially or wholly surrounds the stem, giving the impression that the shoot grows through the leaf such as in Claytonia perfoliata of the purslane family (Portulacaceae).

In some Acacia species, such as the Koa Tree (Acacia koa), the petioles are expanded or broadened and function like leaf blades; these are called phyllodes. There may or may not be normal pinnate leaves at the tip of the phyllode. Species Cannabis indica Cannabis ruderalis Cannabis sativa Cannabis is a genus of flowering plant that includes one or more species. ... Species Aesculus arguta: Texas Buckeye Aesculus californica: California Buckeye Aesculus chinensis: Chinese Horse-chestnut Aesculus flava (): Yellow Buckeye Aesculus glabra: Ohio Buckeye Aesculus hippocastanum: Common Horse-chestnut Aesculus indica: Indian Horse-chestnut Aesculus neglecta: Dwarf Buckeye Aesculus parviflora: Bottlebrush Buckeye Aesculus pavia: Red Buckeye Aesculus sylvatica: Painted Buckeye Aesculus turbinata... Species Many, see text. ... Genera and Species Entandophragma - Sapele - Utile or African Mahogany Guarea - Pink Mahogany Khaya - Ivory Coast Mahogany - Senegal Mahogany Swietenia - Honduras Mahogany - West Indian Mahogany Toona - Indian Mahogany - Chinese Mahogany The name Mahogany was first used in the New World for three trees of the genus Swietenia, namely (West Indian Mahogany... Species About 150 species Albizia is a genus of about 150 species of mostly fast-growing subtropical and tropical trees and shrubs in the Subfamily Mimosoideae of the legume family, Fabaceae. ... Clover (Trifolium) is a genus of about 300 species of plants in the pea family Fabaceae. ... Species Laburnum anagyroides Laburnum alpinum Ref: ILDIS Version 6. ... Subgenera Sorbus Aria Micromeles Cormus Torminaria Chamaemespilus The genus Sorbus, or the Whitebeams, Rowans, and Service Trees, is a genus of about 100-200 species of trees and shrubs in the subfamily Maloideae of the Rose family Rosaceae. ... Genera about 20, see text The Portulacaceae, or purslane family, comprises about 20 genera with about 500 species. ... Species About 1,300; see List of Acacia species Acacia is a genus of shrubs and trees of Gondwanian origin belonging to the subfamily Mimosoideae of the Pea Family Fabaceae, first described from Africa by Linnaeus in 1773. ...

Characteristics of the stipule

• A stipule, present on the leaves of many dicotyledons, is an appendage on each side at the base of the petiole, resembling a small leaf. They may be lasting and not be shed (a stipulate leaf, such as in roses and beans); or be shed as the leaf expands, leaving a stipule scar on the twig (an exstipulate leaf).
• The situation, arrangement, and structure of the stipules is called the stipulation.
  • free
  • adnate : fused to the petiole base
  • ochreate : provided with ochrea, or sheath-formed stipules, e.g. rhubarb,
  • encircling the petiole base
  • interpetiolar : between the petioles of two opposite leaves.
  • intrapetiolar : between the petiole and the subtending stem

Orders see text Dicotyledons or dicots are flowering plants whose seed typically contains two embryonic leaves or cotyledons. ... Species About 100, see text A rose is a flowering shrub of the genus Rosa and the flower of this shrub. ... Green beans Bean is a common name for large plant seeds of several genera of Fabaceae (formerly Leguminosae) used for food or feed. ... Species See text Rhubarb is a perennial plant that grows from thick short rhizomes, comprising the genus Rheum. ...

Venation (arrangement of the veins)

Palmate-veined leaf

There are two subtypes of venation, craspedodromus (the major veins stretch up to the margin of the leaf) and camptodromous (major veins come close to the margin, but bend before they get to it). Palmate-veined leaf File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Palmate-veined leaf File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ...

• Feather-veined, reticulate — the veins arise pinnately from a single mid-vein and subdivide into veinlets. These, in turn, form a complicated network. This type of venation is typical for dicotyledons.
  • Pinnate-netted, penniribbed, penninerved, penniveined; the leaf has usually one main vein (called the mid-vein), with veinlets, smaller veins branching off laterally, usually somewhat parallel to each other; eg Malus (apples).
  • Three main veins originate from the base of the lamina, as in Ceanothus.
  • Palmate-netted, palmate-veined, fan-veined; several main veins diverge from near the leaf base where the petiole attaches, and radiate toward the edge of the leaf; e.g. most Acer (maples).
• Parallel-veined, parallel-ribbed, parallel-nerved, penniparallel — veins run parallel most the length of the leaf, from the base to the apex. Commissural veins (small veins) connect the major parallel veins. Typical for most monocotyledons, such as grasses.
• Dichotomous — There are no dominant bundles, with the veins forking regularly by pairs; found in Ginkgo and some pteridophytes.

Orders see text Dicotyledons or dicots are flowering plants whose seed typically contains two embryonic leaves or cotyledons. ... Species - Southern Crab - Siberian Crabapple - Sweet Crabapple - Apple - Japanese Crabapple - Oregon Crab - Chinese Crabapple - Prairie Crab - Asian Wild Apple - European Wild Apple Malus, the apples, is a genus of about 30-35 species of small deciduous trees or shrubs in the family Rosaceae, including most importantly the domesticated Orchard or... Species See text Ceanothus L., is a genus of about 50-60 species of shrubs or small trees in the buckthorn family Rhamnaceae. ... In vector calculus, the divergence is an operator that measures a vector fields tendency to originate from or converge upon a given point. ... Species with pages written Acer campestre - Field Maple Acer grandidentatum - Bigtooth Maple Acer griseum - Paperbark Maple Acer macrophyllum - Bigleaf Maple Acer micranthum - Komine Maple Acer negundo - Manitoba Maple Acer nigrum - Black Maple Acer palmatum - Japanese Maple Acer pensylvanicum - Striped Maple Acer platanoides - Norway Maple Acer pseudoplatanus - Sycamore Maple Acer rubrum... The term Parallel has a number of important meanings: Parallel (geometry) occurs in geometry. ... Orders Base Monocots: Acorus Alismatales Asparagales Dioscoreales Liliales Pandanales Family Petrosaviaceae Commelinids: Arecales Commelinales Poales Zingiberales Family Dasypogonaceae The Monocotyledons or monocots are an extremely important group of flowering plants, dominating great parts of the earth and with many economically important plants. ... Subfamilies There are 7 subfamilies: Subfamily Arundinoideae Subfamily Bambusoideae Subfamily Centothecoideae Subfamily Chloridoideae Subfamily Panicoideae Subfamily Pooideae Subfamily Stipoideae The true grasses are monocotyledonous plants (Class Liliopsida) in the Family Poaceae, also known as Gramineae. ... Binomial name Ginkgo biloba L. The Ginkgo (Ginkgo biloba), sometimes also known as the Maidenhair Tree, is a unique tree with no close living relatives. ... Classes Marattiopsida Osmundopsida Gleicheniopsida Pteridopsida A fern, or pteridophyte, is any one of a group of some twenty thousand species of plants classified in the Division Pteridophyta, formerly known as Filicophyta. ...

Underside view of leaf

Leaf photo close-up, shot on a Nikon digital camera by Nicholas Moreau (user:zanimum) This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ... Leaf photo close-up, shot on a Nikon digital camera by Nicholas Moreau (user:zanimum) This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ...

Leaf terminology

Shape

See Leaf shape In botany, the following terms are used to describe the shape of plant leaves: cordate leaf Acicular: slender and pointed Alternate (alternifolia): Arranged alternately Bipinnate (bipinnata): Each leaflet also pinnate Cordate (cordata): Heart-shaped, stem attaches to cleft Cuneate: Triangular, stem attaches to point Deltoid: Triangular, stem attaches to side...

Margins (edge)

The leaf margin is characteristic for a genus and aids in determining the species.

• entire: even; with a smooth margin; without toothing
• ciliate: fringed with hairs
• crenate: wavy-toothed; dentate with rounded teeth, such as Fagus (beech)
• dentate: toothed, such as Castanea (chestnut)
  • coarse-toothed: with large teeth
  • glandular toothed: with teeth that bear glands.
• denticulate: finely toothed
• doubly toothed: each tooth bearing smaller teeth, such as Ulmus (elm)
• lobate: indented, with the indentations not reaching to the center, such as many Quercus (oaks)
  • palmately lobed: indented with the indentations reaching to the center, such as Humulus (hop).
• serrate: saw-toothed with asymmetrical teeth pointing forward, such as Urtica (nettle)
• serrulate: finely serrate
• sinuate: with deep, wave-like indentations; coarsely crenate, such as many Rumex (docks)
• spiny: with stiff, sharp points, such as some Ilex (hollies) and Cirsium (thistles).

Species Fagus crenata - Japanese Beech Fagus engleriana - Chinese Beech Fagus grandifolia - American Beech Fagus hayatae - Taiwan Beech Fagus japonica - Japanese Blue Beech Fagus longipetiolata - South Chinese Beech Fagus lucida - Shining Beech Fagus mexicana - Mexican Beech or Haya Fagus orientalis - Oriental Beech Fagus sylvatica - European Beech Beech (Fagus) is a genus... Species - Bush Chinkapin* - Japanese Chestnut - American Chestnut - Henrys Chestnut - Chinese Chestnut - Ozark Chinkapin - Alleghany Chinkapin - Sweet Chestnut - Seguins Chestnut * treated as a synonym of by many authors Chestnuts (Castanea), including the chinkapins, are a genus of eight or nine species of trees and shrubs in the beech family... Species See text Elms are deciduous trees of the genus Ulmus, family Ulmaceae. ... Species See List of Quercus species The term oak can be used as part of the common name of any of several hundred species of trees and shrubs in the genus Quercus, and some related genera, notably Lithocarpus. ... Species Humulus lupulus L. Humulus japonicus Siebold & Zucc. ... Species See text Nettle (Urtica) is a genus of flowering plants in the family Urticaceae, mostly perennial herbs but some are annual and a few are shrubby. ... Species About 200, see text. ... Species Ilex aquifolium - European Holly Ilex canariensis - Small-leaved Holly Ilex cassine - Dahoon Holly Ilex crenata - Japanese Holly Ilex decidua - Possumhaw Ilex dipyrena - Himalayan Holly Ilex glabra - Gallberry, inkberry Ilex latifolia - Tarajo Holly Ilex montana - Mountain Holly Ilex opaca - American Holly Ilex paraguariensis - Yerba Mate Ilex perado - Madeiran Holly Ilex... Species See text Thistles are perennial flowering plants of the genus Cirsium. ...

Tip of the leaf

• acuminate: long-pointed, prolonged into a narrow, tapering point in a concave manner.
• acute: ending in a sharp, but not prolonged point
• cuspidate: with a sharp, elongated, rigid tip; tipped with a cusp.
• emarginate: indented, with a shallow notch at the tip.
• mucronate: abruptly tipped with a small short point, as a continuation of the midrib; tipped with a mucro.
• mucronulate: mucronate, but with a smaller spine.
• obcordate: inversely heart-shaped, deeply notched at the top.
• obtuse: rounded or blunt
• truncate: ending abruptly with a flat end, that looks cut off.

Base of the leaf

• acuminate: coming to a sharp, narrow, prolonged point.
• acute: coming to a sharp, but not prolonged point.
• auriculate: ear-shaped
• cordate: heart-shaped with the norch away from the stem.
• cuneate: wedge-shaped.
• hastate: shaped like an halberd and with the basal lobes pointing outward.
• oblique: slanting.
• reniform: kidney-shaped but rounder and broader than long.
• rounded: curving shape.
• sagittate: shaped like an arrowhead and with the acute basal lobes pointing downward.
• truncate: ending abruptly with a flat end, that looks cut off.

In botany, cuneate is used to describe a leaf or petal base that is narrowly triangular. ...

Surface of the leaf

The surface of a leaf can be described by several botanical terms:

• farinose: bearing farina; mealy, covered with a waxy, whitish powder.
• glabrous: smooth, not hairy.
• glaucous: with a whitish bloom; covered with a very fine, bluish-white powder.
• glutinous: sticky, viscid.
• papillate, papillose: bearing papillae (minute, nipple-shaped protuberances).
• pubescent: covered with erect hairs (especially soft and short ones)
• punctate: marked with dots; dotted with depressions or with translucent glands or colored dots.
• rugose: deeply wrinkled; with veins clearly visible.
• scurfy: covered with tiny, broad scalelike particles.
• tuberculate: covered with tubercles; covered with warty prominences.
• verrucose: warted, with warty outgrowths.
• viscid, viscous: covered with thick, sticky secretions.

Hairiness (trichomes)

Leaves can show several degrees of hairiness. The meaning of several of the following terms can overlap. See also : Trichome. Interior structure of a trichome. ... Interior structure of a trichome. ...

• glabrous: no hairs of any kind present.
• arachnoid, arachnose: with many fine, entangled hairs giving a cobwebby appearance.
• barbellate: with finely barbed hairs (barbellae).
• bearded: with long, stiff hairs.
• bristly: with stiff hair-like prickles.
• canescent: hoary with dense grayish-white pubescence.
• ciliate: marginally fringed with short hairs (cilia).
• ciliolate: minutely ciliate.
• floccose: with flocks of soft, woolly hairs, which tend to rub off.
• glandular: with a gland at the tip of the hair.
• hirsute: with rather rough or stiff hairs.
• hispid: with rigid, bristly hairs.
• hispidulous: minutely hispid.
• hoary: with a fine, close grayish-white pubescence.
• lanate, lanose: with woolly hairs.
• pilose: with soft, clearly separated hairs.
• puberulent, puberulous: with fine, minute hairs.
• pubescent: with soft, short and erect hairs.
• scabrous, scabrid: rough to the touch
• sericeous: silky appearance through fine, straight and appressed (lying close and flat) hairs.
• silky: with adpressed, soft and straight pubescence.
• stellate, stelliform: with star-shaped hairs.
• strigose: with appressed, sharp, straight and stiff hairs.
• tomentose: densely pubescent with matted, soft white woolly hairs.
  • cano-tomentose: between canescent and tomentose
  • felted-tomentose: woolly and matted with curly hairs.
• villous: with long and soft hairs, usually curved.
• woolly: with long, soft and tortuous or matted hairs.

Adaptations

In order to survive in a harsh environment, leaves can adapt in the following ways:

• Hairs develop on the leaf surface to trap humidity in dry climates, creating a large boundary layer to lessen water loss
• Leaves rustle to move humidity away from the surface reducing the boundary layer resistance between the leaf and the air.
• Plant prickles are modified clusters of epidermal hairs
• Waxy leaf surfaces form to prevent water loss
• Small, shiny leaves to deflect the sun's rays
• Thicker leaves to store water (e.g. rhubarb)
• Change to spines instead of laminar (blade) leaves (e.g. cactus)
• Shrink (to phyllodes) or disappear (with the appearance of cladodes), as photosynthetic functions are transferred to the leaf stem (Acacia species)
• Change shape to deflect wind or reduce wind resistance
• Leaves to trap insects (e.g. pitcher plant)
• Change to bulb parts to store food (e.g. onion)
• Produce aromatic oils to deter herbivores (e.g. eucalypts)
• Protect as spines, which are modified leaves.

Wax has traditionally referred to a substance that is secreted by bees (beeswax) and used by them in constructing their honeycombs. ... The Sun (or Sol) is the star at the center of our Solar system. ... Species See text Rhubarb is a perennial plant that grows from thick short rhizomes, comprising the genus Rheum. ... Genera See Taxonomy of the Cactaceae A cactus (plural, cacti or cactuses) is a type of (usually) succulent plant belonging to the dicotyledonous flowering plant family, Cactaceae. ... Phyllodes are modified petioles or leaf stems. ... Species About 1,300; see List of Acacia species Acacia is a genus of shrubs and trees of Gondwanian origin belonging to the subfamily Mimosoideae of the Pea Family Fabaceae, first described from Africa by Linnaeus in 1773. ... Unidentified Nepenthes species, possibly Pitcher plants (or pitfall traps) are carnivorous plants whose prey-trapping mechanism features a deep cavity filled with liquid. ... Binomial name Allium cepa L. Onion in the general sense can be used for any plant in the Genus Allium but used without qualifiers usually means Allium cepa L., also called the garden onion. ... Species About 600, see text Eucalyptus is a diverse genus of trees (rarely shrubs), the members of which dominate the tree flora of Australia. ...

See also

• Cuneate
• Leaf blower
• Vernation

In botany, cuneate is used to describe a leaf or petal base that is narrowly triangular. ... The leaf blower was invented by Japanese engineers in the early 1970s and introduced to the United States as a lawn and garden maintenance tool. ... This Australian tree fern is producing a new frond by the process of circinate vernation Vernation (from vernal, since that is when leaves spring forth in Temperate regions) is the formation of new leaves or fronds. ...

External links

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Leaves

• Position and Arrangement