Open main menu

Wikipedia β

Glossary of leaf morphology

  (Redirected from Leaf shape)

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

Contents

Leaf structureEdit

 
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 shapesEdit

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
  acicular acicularis entire leaf Slender and pointed, needle-like.
  acuminate acuminata leaf tip Tapering to a long point in a concave manner.
  acute leaf tip or base Pointed, having a short sharp apex angled less than 90°.
  apiculate apiculatus leaf tip Tapering and ending in a short, slender point.
  aristate aristata leaf tip Ending 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 leaf With the blade shape different on each side of the midrib.
  caudate leaf tip Tailed at the apex.
  cordate cordata entire leaf Heart-shaped, with the petiole or stem attached to the notch.
  cuneate cuneata leaf base Triangular, wedge-shaped, stem attaches to point.
cuspidate leaf tip With a sharp, elongated, rigid tip; tipped with a cusp.
  deltoid or deltate deltoidea entire leaf Shaped like Greek letter Delta, triangular, stem attaches to side.
  digitate digitata entire leaf With finger-like lobes, similar to palmate.[2]
  elliptic elliptica entire leaf Oval, with a short or no point.
  ensiform ensiformis entire leaf Shaped like a sword, long and narrow with a sharp pointed tip.
  emarginate leaf tip Slightly indented at the tip.
  falcate falcata entire leaf Sickle-shaped.
  fenestrate fenestrata Large openings through the leaf, see perforate. Sometimes use to describes leaf epidermal windows.
filiform filiformis entire leaf Thread- or filament-shaped.
  flabellate flabellata entire leaf Semi-circular, or fan-like.
  hastate hastata entire leaf Spear-shaped: Pointed, with barbs, shaped like a spear point, with flaring pointed lobes at the base.
laciniate entire leaf Very deeply lobed, the lobes being very drawn out, often making the leaf look somewhat like a branch or a pitchfork.
  lanceolate lanceolata entire leaf Long, wider in the middle, shaped like a lance tip.
laminar Flat (like most leaves)
  linear linearis entire leaf Long and very narrow like a blade of grass.
  lobed lobata entire leaf Being divided by clefts, may be pinnately lobed or palmately lobed.
  lorate loratus entire leaf Having the form of a thong or strap.
  lyrate entire 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]
  multifid multi + findere entire leaf Cleft into many parts or lobes.
  obcordate obcordata entire leaf Heart-shaped, stem attaches at the tapering end.
  oblanceolate oblanceolata entire leaf Much longer than wide and with the widest portion near the tip, reversed lanceolate.
  oblique leaf base Asymmetrical leaf base, with one side lower than the other
  oblong oblongus entire leaf Having an elongated form with slightly parallel sides, roughly rectangular.
  obovate obovata entire leaf Teardrop-shaped, stem attaches to the tapering end; reversed ovate.
obtrullate entire leaf Reversed trullate, the longer sides meet at the base rather than the apex.
  obtuse obtusus leaf tip Blunt, forming an angle > 90°.
  orbicular orbicularis entire leaf Circular.
  ovate ovata entire leaf Oval, egg-shaped, with a tapering point and the widest portion near the petiole.
  palmate palmate entire leaf Palm-shaped, i.e. with lobes or leaflets stemming from the leaf base.[4]
  palmately lobed palmate entire leaf Consisting of or lobes[5] radiating from the base of the leaf.
  palmatifid palma + findere entire leaf Palm-shaped, having lobes with incisions that extend less than half-way toward the petiole.
  palmatipartite palma + partiri entire leaf Having lobes with incisions that extend over half-way toward the petiole.
  palmatisect palma + secare entire 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 pedata entire leaf Palmate, with cleft lobes.[6]
  peltate peltata stem attachment A round leaf where the petiole attaches near the center. An example would be a lotus leaf.
  perfoliate perfoliata stem attachment With the leaf blade surrounding the stem such that the stem appears to pass through the leaf.
  perforate perforata leaf surface features Many holes, or perforations on leaf surface. Compare with fenestrate.
  pinnately lobed pinna + lobus entire leaf Having lobes pinnately arranged on the central axis.
  pinnatifid pinna findere entire leaf Having lobes with incisions that extend less than half-way toward the midrib.
  pinnatipartite pinnatus partiri entire leaf Having lobes with incisions that extend more than half-way toward the midrib.
  pinnatisect pinnatus + sectum entire leaf Having lobes with incisions that extend almost, or up to midrib.
plicate plicatus, plicata 3-d shape Folded into pleats, usually lengthwise, serving the function of stiffening a large leaf.
  reniform reniformis entire 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 rhombic rhomboidalis entire leaf Diamond-shaped.
  rounded rotundifolia leaf tip or base Circular, no distinct point.
semiterete 3-d shape Rounded on one side, but flat on the other.
sinuate 3-d shape Circularly-lobed kind of leaves
  sagittate sagittata entire leaf Arrowhead-shaped with the lower lobes folded, or curled downward
  spatulate spathulata entire leaf Spoon-shaped; having a broad flat end which tapers to the base
  spear-shaped entire leaf see hastate.
  subobtuse subobtusa leaf tip or base Somewhat blunted, neither blunt nor sharp
  subulate subulata leaf tip Awl-shaped with a tapering point
terete 3-d shape Circular in cross-section; more or less cylindrical without grooves or ridges.
  trullate entire leaf Shaped like a bricklayer's trowel
  truncate truncata leaf tip or base With a squared-off end
undulate undulatus 3-d shape Wave-like
unifoliate unifoliata compound leaves With a single leaf

EdgeEdit

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
  entire Forma
integra
Even; with a smooth margin; without toothing
  ciliate ciliata Fringed with hairs
  crenate crenata Wavy-toothed; dentate with rounded teeth
crenulate crenulate Finely crenate
crisped curly
  dentate dentata Toothed. May be coarsely dentate, having large teeth, or glandular dentate, having teeth which bear glands
  denticulate denticulata Finely toothed
  doubly serrate duplicato-dentata Each tooth bearing smaller teeth
  serrate serrata Saw-toothed; with asymmetrical teeth pointing forward
  serrulate serrulata Finely serrate
  sinuate sinuosa With deep, wave-like indentations; coarsely crenate
  lobate lobata Indented, with the indentations not reaching the center
lobulate lobulate With small lobes
  undulate undulata With a wavy edge, shallower than sinuate
  spiny or pungent spiculata With stiff, sharp points such as thistles

Leaf foldingEdit

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 keeled carinata with a longitudinal ridge
conduplicate folded upwards, with the surfaces close to parallel
involute rolled upwards (towards the adaxial surface)
  plicate plicata 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

See alsoEdit

ReferencesEdit

  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. 

BibliographyEdit

External linksEdit