The following terms 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 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, carpelsorscales. Some of these terms are also used for similar-looking anatomical features on animals.
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]
Image
Term
Latin
Description
Having two leaflets[1]
geminate
jugate
Having two leaflets, each leaflet being bifoliolate
bipinnatus
The leaflets are themselves pinnately-compound; twice pinnate
With three components, each with three leaflets
With an odd number of leaflets, pinnate with a terminal leaflet (the opposite of paripinnate)
odd-pinnate
Pinnate with an even number of leaflets, lacking a terminal leaflet (the opposite of imparipinnate)
even-pinnate
palmatus
Consisting of leaflets all radiating from one point
pinnatus
Having two rows of leaflets on opposite sides of a central axis, see imparipinnate and paripinnate
Leaf blade in one continuous section, without leaflets (not compound)
ternatus
With three leaflets
trifoliatus
trifoliolatus
tripinnatus
Pinnately compound in which each leaflet is itself bipinnate
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
acicular
acicularis
whole leaf
Slender and pointed, needle-like
acuminate
acuminatus
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
aristatus
leaf tip
Ending in a stiff, bristle-like point
asymmetrical
whole leaf
With the blade shape different on each side of the midrib
attenuate
attenuatus
leaf base
Having leaf tissue taper down the petiole to a narrow base and always having some leaf material on each side of the petiole
auriculate
auriculatus
leaf base
Having ear-shaped appendages reaching beyond the attachment to the petiole or stem (in case of a seated leaf)
caudate
caudatus
leaf tip
Tailed at the apex
cirrus, cirrate
leaf tip
Having a rachis that extends beyond the leaf blade or leaflets into a long whip-like extension or cirrus (common in climbing palms); antonym: ecirrate
cordate, cordiform
cordatus
whole leaf or base
Heart-shaped, with the petiole or stem attached to the notch
cuneate
cuneatus
leaf base
Triangular, wedge-shaped, stem attaches to point
cuneiform
whole leaf
Narrowly triangular, widest on the opposite end from the stem, with the corners at that end rounded
cuspidate
cuspidatus
leaf tip
With a sharp, elongated, rigid tip; tipped with a cusp
deltoid, deltate
deltoideus
whole leaf
Shaped like the Greek letter delta; triangular with stem attached to side
digitate
digitatus
whole leaf
A palmately compound leaf with leaflets, similar to palmate[2]
ecirrate
leaf tip
Without a cirrus; antonym: cirrate
elliptic
ellipticus
whole leaf
Shaped like an ellipse (widest at mid-blade and with similar convex tapering towards apex and base), with a short or no point
emarginate
emarginatus
leaf tip
Slightly indented at the tip
ensiform
ensiformis
whole leaf
Shaped like a sword; long and narrow with a sharp pointed tip
falcate
falcatus
whole leaf
Sickle-shaped
fenestrate
fenestratus
leaf surface features
Large openings through the leaf; see perforate; sometimes used to describe leaf epidermal windows
filiform
filiformis
whole leaf
Thread- or filament-shaped
flabellate
flabellatus
whole leaf
Semi-circular or fan-like
hastate
hastatus
whole leaf or base
Spear-shaped: pointed, with barbs, shaped like a spear point, with flaring pointed lobes at the base
laciniate
lacinatus
whole leaf
Very deeply lobed with the lobes being very drawn out and often making the leaf look somewhat like a branch or a pitchfork
laminar
3-D shape
Flat (like most leaves)
lanceolate
lanceolatus
whole leaf
Long, wider in the middle, shaped like a lance tip
linear
linearis
whole leaf
Long and very narrow like a blade of grass
lobed
lobatus
whole leaf
Being divided by clefts; may be pinnately lobedorpalmately lobed
lorate
loratus
whole leaf
Having the form of a thong or strap
lyrate
lyratus
whole leaf
Shaped like a lyre, pinnately lobed leaf with an enlarged terminal lobe and smaller lateral lobes. See also List of lyrate plants.
mucronate
mucronatus
leaf tip
Ending abruptly in a small sharp point as a continuation of the midrib[3]
multifid
multi + findere
whole leaf
Cleft into many parts or lobes
obcordate
obcordatus
whole leaf
Heart-shaped, stem attaches at the tapering end
oblanceolate
oblanceolatus
whole 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
whole leaf
Having an elongated form with slightly parallel sides; roughly rectangular
obovate
obovatus
whole leaf
Teardrop-shaped, stem attaches to the tapering end; reversed ovate
obtrullate
whole leaf
Reversed trullate; the longer sides meet at the base rather than the apex.
obtuse
obtusus
leaf tip or base
Blunt, forming an angle > 90°
orbicular
orbicularis
whole leaf
Circular
ovate
ovatus
whole leaf
Egg-shaped, with a tapering point and the widest portion near the petiole
palmate
palmatus
whole leaf
Palm-shaped, i.e. with lobes or leaflets stemming from the leaf base[4]
palmately lobed
palmatus
whole leaf
Lobes spread radially from a point[5]
palmatifid
palma + findere
whole leaf
Palm-shaped, having lobes with incisions that extend less than halfway toward the petiole
palmatipartite
palma + partiri
whole leaf
Having palmate lobes with incisions that extend over halfway toward the petiole
palmatisect
palma + secare
whole leaf
Having palmate lobes with incisions that extend almost up, but not quite to the petiole.
pandurate
panduratus
whole leaf
Fiddle-shaped; obovate with a constriction near the middle.
pedate
pedatus
whole leaf
Palmate, with cleft lobes[6]
peltate
peltatus
stem attachment
A round leaf where the petiole attaches near the center, e.g. a lotus leaf
perfoliate
perfoliatus
stem attachment
With the leaf blade surrounding the stem such that the stem appears to pass through the leaf
perforate
perforatus
leaf surface features
Many holes, or perforations, on leaf surface. Compare with fenestrate.
pinnately lobed
pinna + lobus
whole leaf
Having lobes pinnately arranged on the central axis
pinnatifid
pinna + findere
whole leaf
Having lobes with incisions that extend less than halfway to the midrib
pinnatipartite
pinnatus + partiri
whole leaf
Having lobes with incisions that extend more than halfway to the midrib
pinnatisect
pinnatus + sectus
whole leaf
Having lobes with incisions that extend almost to, or up to, the midrib
plicate
plicatus
3-D shape
Folded into pleats, usually lengthwise, serving the function of stiffening a large leaf
reniform
reniformis
whole leaf
Shaped like a kidney, with an inward curve on one side
retuse
leaf tip
With a shallow notch in a round apex
rhomboid, rhombic
rhomboidalis
whole leaf
Diamond-shaped
rounded
rotundifolius
leaf tip or base
Circular, no distinct point
semiterete
3-D shape
Rounded on one side and flat on the other
sinuate
sinuatus
3-D shape
Circularly-lobed leaves
sagittate
sagittatus
whole leaf
Arrowhead-shaped with the lower lobes folded, or curled downward
spatulate
spathulatus
whole leaf
Spoon-shaped; having a broad flat end which tapers to the base
spear-shaped
hastatus
whole leaf
See hastate.
subobtuse
subobtusus
leaf tip or base
Somewhat blunted; neither blunt nor sharp
subulate
subulatus
leaf tip
Awl-shaped with a tapering point
3-D shape
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.
trullate
whole leaf
Shaped like a masonry trowel
truncate
truncatus
leaf tip or base
With a squared-off end
undulate
undulatus
3-D shape
Wave-like
unifoliate
unifoliatus
compound leaves
With a single leaflet; it is distinct from a simple leaf by the presence of two abscission layers and often by petiolules and stipels.
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
orglandular 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
undulate
undulatus
With a wavy edge, shallower than sinuate
spiny or pungent
spiculatus
With stiff, sharp points such as thistles
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.
Image
Term
Latin
Description
carinate or keeled
carinatus
With a longitudinal ridge, keel-shaped
conduplicate
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
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]
