Glossary of leaf morphology

The following is a defined list of terms which are used to describe leaf morphology 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 a 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 compromise by qualifying terms so vaguely that the description practically loses its value in trying say, to identify a particular plant or phrase a key entry helpfully.

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:

Image Term Latin Description
bifoliolateHaving two leaflets[1]
geminate
jugate
bigeminateHaving two leaflets, each leaflet being bifoliolate
bipinnatebipinnatusThe leaflets are themselves pinnately-compound; twice pinnate
biternateWith three components, each with three leaflets
imparipinnateWith an odd number of leaflets, pinnate with a terminal leaflet (the opposite of paripinnate)
odd-pinnate
paripinnatePinnate with an even number of leaflets, lacking a terminal leaflet (the opposite of imparipinnate)
even-pinnate
palmately compoundpalmatusConsisting of leaflets all radiating from one point
pinnately compoundpinnatus Having two rows of leaflets on opposite sides of a central axis, see imparipinnate and paripinnate
simpleLeaf blade in one continuous section, without leaflets (not compound)
ternateternatusWith three leaflets
trifoliate trifoliatus
trifoliolate trifoliolatus
tripinnatetripinnatusPinnately 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.

Image Term Latin Refers principally to Description
acicularacicularisentire leafSlender and pointed, needle-like.
acuminateacuminatusleaf tipTapering to a long point in a concave manner.
acuteleaf tip or basePointed, having a short sharp apex angled less than 90°.
apiculateapiculatusleaf tipTapering and ending in a short, slender point.
aristatearistatusleaf tipEnding in a stiff, bristle-like point.
attenuateattenuatus leaf baseHaving leaf tissue taper down the petiole to a narrow base, always having some leaf material on each side of the petiole.
auriculateauriculatus leaf baseHaving ear-shaped appendages reaching beyond the attachment to the petiole or to the stem (in case of a seated leaf).
asymmetricalentire leafWith the blade shape different on each side of the midrib.
caudate caudatusleaf tipTailed at the apex.
cordatecordatusentire leafHeart-shaped, with the petiole or stem attached to the notch.
cuneatecuneatusleaf baseTriangular, wedge-shaped, stem attaches to point.
cuspidatecuspidatusleaf tipWith a sharp, elongated, rigid tip; tipped with a cusp.
deltoid or deltatedeltoideusentire leafShaped like Greek letter Delta, triangular, stem attaches to side.
digitatedigitatusentire leafWith finger-like lobes, similar to palmate.[2]
ellipticellipticusentire leafOval, with a short or no point.
ensiformensiformisentire leafShaped like a sword, long and narrow with a sharp pointed tip.
emarginateemarginatus leaf tipSlightly indented at the tip.
falcatefalcatusentire leafSickle-shaped.
fenestratefenestratussurface featuresLarge openings through the leaf, see perforate. Sometimes use to describes leaf epidermal windows.
filiformfiliformisentire leafThread- or filament-shaped.
flabellateflabellatusentire leafSemi-circular, or fan-like.
hastatehastatusentire leafSpear-shaped: Pointed, with barbs, shaped like a spear point, with flaring pointed lobes at the base.
laciniatelacinatus entire leafVery deeply lobed, the lobes being very drawn out, often making the leaf look somewhat like a branch or a pitchfork.
lanceolatelanceolatusentire leafLong, wider in the middle, shaped like a lance tip.
laminar3-d shape Flat (like most leaves)
linearlinearisentire leafLong and very narrow like a blade of grass.
lobedlobatusentire leafBeing divided by clefts, may be pinnately lobed or palmately lobed.
lorateloratusentire leafHaving the form of a thong or strap.
lyratelyratusentire leafShaped like a lyre, pinnately lobed leaf with an enlarged terminal lobe and smaller lateral lobes.
mucronate mucronatus leaf tipEnding abruptly in a small sharp point as a continuation of the midrib.[3]
multifidmulti + findereentire leafCleft into many parts or lobes.
obcordateobcordatusentire leafHeart-shaped, stem attaches at the tapering end.
oblanceolateoblanceolatusentire leafMuch longer than wide and with the widest portion near the tip, reversed lanceolate.
obliqueleaf baseAsymmetrical leaf base, with one side lower than the other
oblongoblongusentire leafHaving an elongated form with slightly parallel sides, roughly rectangular.
obovateobovatusentire leafTeardrop-shaped, stem attaches to the tapering end; reversed ovate.
obtrullateentire leafReversed trullate, the longer sides meet at the base rather than the apex.
obtuseobtusustipBlunt, forming an angle > 90°.
orbicularorbicularisentire leafCircular.
ovateovatusentire leafOval, egg-shaped, with a tapering point and the widest portion near the petiole.
palmatepalmatusentire leafPalm-shaped, i.e., with lobes or leaflets stemming from the leaf base.[4]
palmately lobedpalmatusentire leafLobes spread radially from a point. [5]
palmatifid palma + findereentire leafPalm-shaped, having lobes with incisions that extend less than half-way toward the petiole.
palmatipartitepalma + partirientire leafHaving lobes with incisions that extend over half-way toward the petiole.
palmatisectpalma + secareentire leafHaving lobes with incisions that extend almost up, but not quite to the petiole.
pandurate panduratus entire leafFiddle-shaped; obovate with a constriction near the middle.
pedate pedatusentire leafPalmate, with cleft lobes.[6]
peltatepeltatusstem attachmentA round leaf where the petiole attaches near the center. An example would be a lotus leaf.
perfoliateperfoliatusstem attachmentWith the leaf blade surrounding the stem such that the stem appears to pass through the leaf.
perforateperforatusleaf surface features Many holes, or perforations on leaf surface. Compare with fenestrate.
pinnately lobedpinna + lobusentire leafHaving lobes pinnately arranged on the central axis.
pinnatifid pinna + findereentire leafHaving lobes with incisions that extend less than half-way toward the midrib.
pinnatipartitepinnatus + partirientire leafHaving lobes with incisions that extend more than half-way toward the midrib.
pinnatisect pinnatus + sectusentire leafHaving lobes with incisions that extend almost, or up to midrib.
plicateplicatus3-d shapeFolded into pleats, usually lengthwise, serving the function of stiffening a large leaf.
reniformreniformisentire leafShaped like a kidney: an oval with an inward curve on one side.
retuse leaf tipWith a shallow notch in a round apex.
rhomboid or rhombicrhomboidalisentire leafDiamond-shaped.
roundedrotundifoliusleaf tip or baseCircular, no distinct point.
semiterete3-d shapeRounded on one side, but flat on the other.
sinuatesinuatus 3-d shapeCircularly-lobed kind of leaves
sagittatesagittatusentire leafArrowhead-shaped with the lower lobes folded, or curled downward
spatulatespathulatusentire leafSpoon-shaped; having a broad flat end which tapers to the base
spear-shapedhastatus entire leafsee hastate.
subobtusesubobtususleaf tip or baseSomewhat blunted, neither blunt nor sharp
subulatesubulatusleaf tipAwl-shaped with a tapering point
terete3-d shapeCircular in cross-section; more or less cylindrical without grooves or ridges.
trullate entire leafShaped like a bricklayer's trowel
truncatetruncatusleaf tip or baseWith a squared-off end
undulateundulatus3-d shapeWave-like
unifoliateunifoliatuscompound leavesWith a single leaflet. It is distinct from a simple leaf by the presence of two abcission layers and often by petiolules and stipels

Edge

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 adjective Description
entireForma
integra
Even; with a smooth margin; without toothing
ciliateciliatusFringed with hairs
crenatecrenatusWavy-toothed; dentate with rounded teeth
crenulatecrenulateFinely crenate
crispedcrispuscurly
dentatedentatusToothed. May be coarsely dentate, having large teeth, or glandular dentate, having teeth which bear glands
denticulatedenticulatusFinely toothed
doubly serrateduplicato-dentatusEach tooth bearing smaller teeth
serrateserratusSaw-toothed; with asymmetrical teeth pointing forward
serrulateserrulatusFinely serrate
sinuatesinuosusWith deep, wave-like indentations; coarsely crenate
lobatelobatusIndented, with the indentations not reaching the center
lobulatelobulatusWith small lobes
undulateundulatusWith a wavy edge, shallower than sinuate
spiny or pungentspiculatusWith stiff, sharp points such as thistles

Leaf folding

Leaves may also be folded 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.

Image Term Latin Description
carinate or keeledcarinatuswith a longitudinal ridge
conduplicatefolded upwards, with the surfaces close to parallel
cucullateforming a hood, margins and tip curved downward
involuterolled upwards (towards the adaxial surface)
plicateplicatuswith parallel folds
reduplicatefolded downwards, with the surfaces close to parallel
revoluterolled downwards (towards the abaxial surface)
supervoluteopposing 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]

See also

References

  1. Radford, A. E., W. C. Dickison, J. R. Massey, C. R. Bell (1976), "Phytography - Morphological Evidence", Vascular Plant Systematics, Harper and Row, New YorkCS1 maint: uses authors parameter (link)
  2. Also used to describe compound leaves with finger-like leaflets.
  3. Mucronate, Answers.com, from Roget's Thesaurus.
  4. "palmate (adj. palmately)". GardenWeb Glossary of Botanical Terms.
  5. "Leaf description glossary". www.cs.rochester.edu. Retrieved 2017-11-02.
  6. "Pedate leaf". Retrieved February 24, 2014.
  7. Stearn (2004), pp. 439–440.

Bibliography

This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.