The following terms are used to describe leafmorphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular or irregular, may be smooth or bearing hair, bristles or spines. For more terms describing other aspects of leaves besides their overall morphology see the leaf article.
The terms listed here all are supported by technical and professional usage, but they cannot be represented as mandatory or undebatable; readers must use their judgement. Authors often use terms arbitrarily, or coin them to taste, possibly in ignorance of established terms, and it is not always clear whether because of ignorance, or personal preference, or because usages change with time or context, or because of variation between specimens, even specimens from the same plant. For example, whether to call leaves on the same tree "acuminate", "lanceolate", or "linear" could depend on individual judgement, or which part of the tree one collected them from. The same cautions might apply to "caudate", "cuspidate", and "mucronate", or to "crenate", "dentate", and "serrate".
Another problem is to establish definitions that meet all cases or satisfy all authorities and readers. For example, it seems altogether reasonable to define a mucro as "a small sharp point as a continuation of the midrib", but it may not be clear how small is small enough, how sharp is sharp enough, how hard the point must be, and what to call the point when one cannot tell whether the leaf has a midrib at all. Various authors or field workers might come to incompatible conclusions, or might try to compromise by qualifying terms so vaguely that a description of a particular plant practically loses its value.
Use of these terms is not restricted to leaves, but may be applied to morphology of other parts of plants, e.g. bracts, bracteoles, stipules, sepals, petals, carpels or scales. Some of these terms are also used for similar-looking anatomical features on animals.
Leaf structure
Leaves of most plants include a flat structure called the blade or lamina, but not all leaves are flat, some are cylindrical. Leaves may be simple, with a single leaf blade, or compound, with several leaflets. In flowering plants, as well as the blade of the leaf, there may be a petiole and stipules; compound leaves may have a rachis supporting the leaflets. Leaf structure is described by several terms that include:[citation needed]
Bipinnate leaf anatomy with labels showing alternative usagesA ternate compound leaf with a petiole but no rachis (or rachillae)
Pinnately compound in which each leaflet is itself bipinnate
Leaf and leaflet shapes
Being one of the more visible features, leaf shape is commonly used for plant identification. Similar terms are used for other plant parts, such as petals, tepals, and bracts.
Cylindrical with a circular or distorted circular cross-section and a single surface wrapping around it with no grooves or ridges. Subterete means the leaves are not completely terete, as seen in various lichens and succulents.
Leaf margins (edges) are frequently used in visual plant identification because they are usually consistent within a species or group of species, and are an easy characteristic to observe. Edge and margin are interchangeable in the sense that they both refer to the outside perimeter of a leaf.
Image
Term
Latin
Description
entire
Forma integra
Even; with a smooth margin; without toothing
ciliate
ciliatus
Fringed with hairs
crenate
crenatus
Wavy-toothed; dentate with rounded teeth
crenulate
crenulatus
Finely crenate
crisped
crispus
Curly
dentate
dentatus
Toothed;
may be coarsely dentate, having large teeth
or glandular dentate, having teeth which bear glands
denticulate
denticulatus
Finely toothed
doubly serrate
duplicato-dentatus
Each tooth bearing smaller teeth
serrate
serratus
Saw-toothed; with asymmetrical teeth pointing forward
serrulate
serrulatus
Finely serrate
sinuate
sinuosus
With deep, wave-like indentations; coarsely crenate
lobate
lobatus
Indented, with the indentations not reaching the center
Leaves may also be folded, sculpted or rolled in various ways. If the leaves are initially folded in the bud, but later unrolls it is called vernation, ptyxis is the folding of an individual leaf in a bud.
Folded upwards, with the surfaces close to parallel
cucullate
Forming a hood, margins and tip curved downward
involute
Rolled upwards (towards the adaxial surface)
plicate
plicatus
With parallel folds
reduplicate
Folded downwards, with the surfaces close to parallel
revolute
Rolled downwards (towards the abaxial surface)
supervolute
Opposing left and right halves of lamina folded along longitudinal axis, with one half rolled completely within the other
Latin descriptions
The Latin word for 'leaf', folium, is neuter. In descriptions of a single leaf, the neuter singular ending of the adjective is used, e.g. folium lanceolatum 'lanceolate leaf', folium lineare 'linear leaf'. In descriptions of multiple leaves, the neuter plural is used, e.g. folia linearia 'linear leaves'. Descriptions commonly refer to the plant using the ablative singular or plural, e.g. foliis ovatis 'with ovate leaves'.[7]
Pinnation is the arrangement of feather-like or multi-divided features arising from both sides of a common axis. Pinnation occurs in biological morphology, in crystals, such as some forms of ice or metal crystals, and in patterns of erosion or stream beds.
A leaflet in botany is a leaf-like part of a compound leaf. Though it resembles an entire leaf, a leaflet is not borne on a main plant stem or branch, as a leaf is, but rather on a petiole or a branch of the leaf. Compound leaves are common in many plant families and they differ widely in morphology. The two main classes of compound leaf morphology are palmate and pinnate. For example, a hemp plant has palmate compound leaves, whereas some species of Acacia have pinnate leaves.
A frond is a large, divided leaf. In both common usage and botanical nomenclature, the leaves of ferns are referred to as fronds and some botanists restrict the term to this group. Other botanists allow the term frond to also apply to the large leaves of cycads, as well as palms (Arecaceae) and various other flowering plants, such as mimosa or sumac. "Frond" is commonly used to identify a large, compound leaf, but if the term is used botanically to refer to the leaves of ferns and algae it may be applied to smaller and undivided leaves.
In botany, a stipe is a stalk that supports some other structure. The precise meaning is different depending on which taxonomic group is being described.
In botany, a stipule is an outgrowth typically borne on both sides of the base of a leafstalk. Stipules are considered part of the anatomy of the leaf of a typical flowering plant, although in many species they may be inconspicuous —or sometimes entirely absent, and the leaf is then termed exstipulate. The word stipule was coined by Linnaeus from Latin stipula, straw, stalk.
Nepenthes klossii is a tropical pitcher plant endemic to New Guinea.
Nepenthes surigaoensis is a tropical pitcher plant endemic to the Philippine island of Mindanao, where it grows at elevations of at least 800–1200 m above sea level.
In botany, the petiole is the stalk that attaches the leaf blade to the stem. It is able to twist the leaf to face the sun, producing a characteristic foliage arrangement, and also optimizing its exposure to sunlight. Outgrowths appearing on each side of the petiole in some species are called stipules. The terms petiolate and apetiolate are applied respectively to leaves with and without petioles.
Cussonia is a genus of plants of the family Araliaceae, which is native to the Afrotropics. It originated in Africa and has its center of distribution in South Africa and the Mascarene Islands. Due to their striking habit, they are a conspicuous and easily recognizable group of plants. Their genus name commemorates the botanist Pierre Cusson. The Afro-Malagasy and Asian Schefflera, and Afrotropical Seemannaralia genera are related taxa that share several of its morphological characteristics, among which the leaves borne on the end of branches, inflorescences carried on terminal branches or stems, and reduced leaf complexity in developing inflorescences.
This page provides a glossary of plant morphology. Botanists and other biologists who study plant morphology use a number of different terms to classify and identify plant organs and parts that can be observed using no more than a handheld magnifying lens. This page provides help in understanding the numerous other pages describing plants by their various taxa. The accompanying page—Plant morphology—provides an overview of the science of the external form of plants. There is also an alphabetical list: Glossary of botanical terms. In contrast, this page deals with botanical terms in a systematic manner, with some illustrations, and organized by plant anatomy and function in plant physiology.
This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary of leaf morphology. For other related terms, see Glossary of phytopathology, Glossary of lichen terms, and List of Latin and Greek words commonly used in systematic names.
A leaf is a principal appendage of the stem of a vascular plant, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, flower, and fruit collectively form the shoot system. In most leaves, the primary photosynthetic tissue is the palisade mesophyll and is located on the upper side of the blade or lamina of the leaf but in some species, including the mature foliage of Eucalyptus, palisade mesophyll is present on both sides and the leaves are said to be isobilateral. Most leaves are flattened and have distinct upper (adaxial) and lower (abaxial) surfaces that differ in color, hairiness, the number of stomata, the amount and structure of epicuticular wax and other features. Leaves are mostly green in color due to the presence of a compound called chlorophyll which is essential for photosynthesis as it absorbs light energy from the sun. A leaf with lighter-colored or white patches or edges is called a variegated leaf.
In botany, sessility is a characteristic of plant parts that have no stalk. Plant parts can also be described as subsessile, that is, not completely sessile.
Lepidobotryaceae is a family of plants in the order Celastrales. It contains only two species: Lepidobotrys staudtii and Ruptiliocarpon caracolito.
Ruptiliocarpon is a monotypic genus of flowering plants in the family Lepidobotryaceae. The genus has only one species, Ruptiliocarpon caracolito. It is a tall tree that grows in several small isolated areas of Central and South America. It is known from Costa Rica, Colombia, Peru, and Suriname. It is locally common on hillsides and other well-drained areas, often in red clay, from near sea level to 400 m in elevation.
In plant morphology, thorns, spines, and prickles, and in general spinose structures, are hard, rigid extensions or modifications of leaves, roots, stems, or buds with sharp, stiff ends, and generally serve the same function: physically defending plants against herbivory.
In botany, a whorl or verticil is a whorled arrangement of leaves, sepals, petals, stamens, or carpels that radiate from a single point and surround or wrap around the stem or stalk. A leaf whorl consists of at least three elements; a pair of opposite leaves is not called a whorl.
Salix caspica is a plant from the willow genus (Salix) within the willow family (Salicaceae). The natural range extends from eastern European Russia to far western China.
Mallotus plicatus is a tree or shrub in the Euphorbiaceae family, in the Polyadenii section. It occurs in much of Mainland Southeast Asia. It is used for dyeing and in construction.
Symphyotrichum kentuckiense is a rare species of flowering plant in the Asteraceae family and is commonly known as Kentucky aster, Price's aster, Miss Price's aster, Sadie's aster, or lavender oldfield aster. It is a perennial, herbaceous plant that is endemic to broken limestone cedar glades and roadsides in Alabama, Georgia, Kentucky, and Tennessee. It blooms from August through October, reaches heights between 30 centimeters and 100 cm (3.3 ft), and has green to reddish-brown stems. It is a nearly hairless plant with blue to blue-violet ray florets.
↑ "palmate (adj. palmately)". GardenWeb Glossary of Botanical Terms. iVillage GardenWeb. 2006. Archived from the original on 13 February 2009. Retrieved 19 October 2008.
Massey, Jimmy R.; Murphy, James C. (1996). "Vascular plant systematics". NC Botnet. University of North Carolina at Chapel Hill. Retrieved 19 January 2016.
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