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.

Chart illustrating leaf morphology terms

Leaf structure

A ternate compound leaf with a petiole but no rachis (or rachillae)

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
bifoliolate Having two leaflets[1]
geminate
jugate
bigeminate Having two leaflets, each leaflet being bifoliolate
bipinnate bipinnata The leaflets are themselves pinnately-compound; twice pinnate
biternate With three components, each with three leaflets
imparipinnate With an odd number of leaflets, pinnate with a terminal leaflet (the opposite of paripinnate)
odd-pinnate
paripinnate Pinnate with an even number of leaflets, lacking a terminal leaflet (the opposite of imparipinnate)
even-pinnate
palmately compound Consisting of leaflets all radiating from one point
pinnately compound Having two rows of leaflets on opposite sides of a central axis, see imparipinnate and paripinnate
simple Leaf blade in one continuous section, without leaflets (not compound)
ternate ternata With three leaflets
trifoliate trifoliata
trifoliolate trifoliolata
tripinnate tripinnata 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 tepals)

Oddly pinnate, pinnatifid leaves (Apium graveolens, celery)
Partial chlorosis revealing palmate venation in simple leaves of Hibiscus mutabilis
Image Term Latin Refers principally to Description
acicularacicularisentire leaf Slender and pointed, needle-like.
acuminateacuminataleaf tip Tapering to a long point in a concave manner.
acute leaf tip or basePointed, having a short sharp apex angled less than 90°.
apiculate apiculatus leaf tip Tapering and ending in a short, slender point.
aristatearistata leaf tipEnding in a stiff, bristle-like point.
attenuate leaf base Having leaf tissue taper down the petiole to a narrow base, always having some leaf material on each side of the petiole.
auriculate leaf base Having ear-shaped appendages near the petiole.
asymmetrical entire leafWith the blade shape different on each side of the midrib.
caudate leaf tip Tailed at the apex.
cordatecordata entire leafHeart-shaped, with the petiole or stem attached to the notch.
cuneatecuneataleaf baseTriangular, wedge-shaped, stem attaches to point.
cuspidate leaf tip With a sharp, elongated, rigid tip; tipped with a cusp.
deltoid or deltatedeltoideaentire leaf Shaped like Greek letter Delta, triangular, stem attaches to side.
digitate digitataentire leaf With finger-like lobes, similar to palmate.[2]
ellipticellipticaentire leaf Oval, with a short or no point.
ensiformensiformisentire leaf Shaped like a sword, long and narrow with a sharp pointed tip.
emarginate leaf tip Slightly indented at the tip.
falcatefalcataentire leaf Sickle-shaped.
fenestrate fenestrata Large openings through the leaf, see perforate. Sometimes use to describes leaf epidermal windows.
filiform filiformisentire leaf Thread- or filament-shaped.
flabellateflabellata entire leafSemi-circular, or fan-like.
hastatehastata entire leafSpear-shaped: Pointed, with barbs, shaped like a spear point, with flaring pointed lobes at the base.
laciniate entire leafVery deeply lobed, the lobes being very drawn out, often making the leaf look somewhat like a branch or a pitchfork.
lanceolatelanceolata entire leafLong, wider in the middle, shaped like a lance tip.
laminar Flat (like most leaves)
linearlinearisentire leaf Long and very narrow like a blade of grass.
lobedlobataentire leaf Being divided by clefts, may be pinnately lobed or palmately lobed.
lorateloratusentire leaf Having the form of a thong or strap.
lyrateentire leaf Shaped like a lyre, pinnately lobed leaf with an enlarged terminal lobe and smaller lateral lobes.
mucronate leaf tip Ending abruptly in a small sharp point as a continuation of the midrib.[3]
multifidmulti + findereentire leaf Cleft into many parts or lobes.
obcordateobcordataentire leaf Heart-shaped, stem attaches at the tapering end.
oblanceolateoblanceolataentire leaf Much 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 leaf Having an elongated form with slightly parallel sides, roughly rectangular.
obovateobovataentire leaf Teardrop-shaped, stem attaches to the tapering end; reversed ovate.
obtrullateentire leaf Reversed trullate, the longer sides meet at the base rather than the apex.
obtuseobtusus leaf tipBlunt, forming an angle > 90°.
orbicularorbicularis entire leafCircular.
ovateovataentire leaf Oval, egg-shaped, with a tapering point and the widest portion near the petiole.
palmatepalmateentire leafPalm-shaped, i.e. with lobes or leaflets stemming from the leaf base.[4]
palmately lobedpalmateentire leafConsisting of or lobes[5] radiating from the base of the leaf.
palmatifid palma + findere entire leafPalm-shaped, having lobes with incisions that extend less than half-way toward the petiole.
palmatipartitepalma + partirientire leaf Having lobes with incisions that extend over half-way toward the petiole.
palmatisectpalma + secareentire leaf Having lobes with incisions that extend almost up, but not quite to the petiole.
pandurate entire leaf Fiddle-shaped; obovate with a constriction near the middle.
pedate pedataentire leaf Palmate, with cleft lobes.[6]
peltatepeltatastem attachment A round leaf where the petiole attaches near the center. An example would be a lotus leaf.
perfoliateperfoliatastem attachment With the leaf blade surrounding the stem such that the stem appears to pass through the leaf.
perforate perforataleaf surface features Many holes, or perforations on leaf surface. Compare with fenestrate.
pinnately lobedpinna + lobusentire leaf Having lobes pinnately arranged on the central axis.
pinnatifid pinna findereentire leaf Having lobes with incisions that extend less than half-way toward the midrib.
pinnatipartitepinnatus partirientire leaf Having lobes with incisions that extend more than half-way toward the midrib.
pinnatisect pinnatus + sectum entire leafHaving lobes with incisions that extend almost, or up to midrib.
plicate plicatus, plicata3-d shape Folded into pleats, usually lengthwise, serving the function of stiffening a large leaf.
reniformreniformisentire leaf Shaped like a kidney: an oval with an inward curve on one side.
retuse leaf tip With a shallow notch in a round apex.
rhomboid or rhombicrhomboidalis entire leafDiamond-shaped.
rounded rotundifolialeaf tip or baseCircular, no distinct point.
semiterete 3-d shapeRounded on one side, but flat on the other.
Template:Sinuate3-d shapeCircularly Lobed kind of leaves
sagittatesagittataentire leaf Arrowhead-shaped with the lower lobes folded, or curled downward
spatulatespathulataentire leaf Spoon-shaped; having a broad flat end which tapers to the base
spear-shaped entire leaf see hastate.
subobtusesubobtusaleaf tip or baseSomewhat blunted, neither blunt nor sharp
subulatesubulataleaf 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
truncatetruncataleaf tip or base With a squared-off end
undulate undulatus3-d shapeWave-like
unifoliate unifoliatacompound leaves With a single leaf

Edge

Leaf margins (edges) are frequently used in visual plant identification due to the fact that they are usually consistent within a species or group of species, the leaf edges are also an easy to observe characteristic which makes them even more useful for identification. Edge and margin are both interchangeable in the sense that they refer to the outside perimeter of a leaf.

Image Term Latin Description
entireForma
integra
Even; with a smooth margin; without toothing
ciliateciliataFringed with hairs
crenatecrenataWavy-toothed; dentate with rounded teeth
crenulatecrenulateFinely crenate
crispedcurly
dentatedentataToothed. May be coarsely dentate, having large teeth, or glandular dentate, having teeth which bear glands
denticulatedenticulataFinely toothed
doubly serrateduplicato-dentataEach tooth bearing smaller teeth
serrateserrataSaw-toothed; with asymmetrical teeth pointing forward
serrulateserrulataFinely serrate
sinuatesinuosaWith deep, wave-like indentations; coarsely crenate
lobatelobataIndented, with the indentations not reaching the center
lobulatelobulateWith small lobes
undulateundulataWith a wavy edge, shallower than sinuate
spiny or pungentspiculataWith stiff, sharp points such as thistles

Leaf folding

Leaves may also be folded or rolled in various ways. The folding of leaves within a bud is vernation, ptyxis is the folding of an individual leaf in a bud.

Image Term Latin Description
carinate or keeledcarinatawith a longitudinal ridge
conduplicatefolded upwards, with the surfaces close to parallel
involuterolled upwards (towards the adaxial surface)
plicateplicatawith 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

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 York
  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. "palmate (adj. palmately)". GardenWeb Glossary of Botanical Terms.
  6. "Pedate leaf". Retrieved February 24, 2014.

Bibliography

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