Glossary of leaf morphology

Chart illustrating leaf morphology terms

The following terms are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (that is, the leaf blade or 'lamina' is undivided) or compound (that is, the leaf blade is divided into two or more leaflets). The edge of the leaf may be regular or irregular, and may be smooth or have 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 supported by a network of veins, a petiole and a leaf base; but not all leaves are flat, some are cylindrical. Leaves may be simple, with a single leaf blade, or compound, with several leaflets. Compound leaves may be pinnate with pinnae (leaflets) on both sides of a rachis (axis), or may be palmate with multiple leaflets arising from a single point. Leaf structure is described by several terms that include:

Bipinnate leaf anatomy with labels showing alternative usages

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

Image	Term	Latin	Description
	bifoliolate		Having two leaflets
	geminate
	jugate
	bigeminate		Having two leaflets, each leaflet being bifoliolate
File:Leaf morphology bipinnate.png	bipinnate		The leaflets are themselves pinnately-compound; twice pinnate see imparipinnate and paripinnate
File:Leaf morphology Biternate.png	biternate		With three components, each with three leaflets
File:Leaf morphology odd pinnate.png	imparipinnate		With an odd number of leaflets, pinnate with a terminal leaflet (the opposite of paripinnate)
	odd-pinnate
File:Leaf morphology even pinnate.png	paripinnate		Pinnate with an even number of leaflets, lacking a terminal leaflet (the opposite of imparipinnate)
	even-pinnate
File:Leaf morphology Palmately compound.png	palmately compound	palmatus	Consisting of leaflets all radiating from one point
File:Leaf morphology Acute.png	simple		Leaf blade in one continuous section, without leaflets (not compound)
File:Leaf morphology trifoliolate.png	ternate		With three leaflets
	trifoliate
	trifoliolate
File:Leaf morphology tripinnate.png	tripinnate		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.

File:Cilantro leaf.jpg

Oddly pinnate, pinnatifid leaves (Coriandrum sativum, coriander or cilantro)

File:Hibiscus mutabilis 5.JPG

Partial chlorosis revealing palmate venation in simple leaves of Hibiscus mutabilis

Image	Term	Latin	Refers principally to	Description
File:Leaf morphology acicular.png	acicular		whole leaf	Slender and pointed, needle-like
File:Leaf morphology acuminate.png	acuminate		leaf tip	Tapering to a long point in a concave manner
File:Leaf morphology Acute.png	acute		leaf tip or base	Pointed, having a short sharp apex angled less than 90°
File:Leaf morphology Apiculate.png	apiculate		leaf tip	Tapering and ending in a short, slender point
File:Leaf morphology aristate.png	aristate		leaf tip	Ending in a stiff, bristle-like point
	asymmetrical		whole leaf	With the blade shape different on each side of the midrib
File:Leaf morphology Attenuate.png	attenuate		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
File:Leaf morphology base auriculate (cropped).png	auriculate		leaf base	Having ear-shaped appendages reaching beyond the attachment to the petiole or stem (in case of a seated leaf)
File:Leaf morphology Caudate.png	caudate		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
File:Leaf morphology cordate.png	cordate, cordiform		whole leaf or base	Heart-shaped, with the petiole or stem attached to the notch
File:Leaf morphology cuneate.png	cuneate		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
File:Handdrawn Cuspidate.png	cuspidate		leaf tip	With a sharp, elongated, rigid tip; tipped with a cusp
File:Leaf morphology deltoid.png	deltoid, deltate		whole leaf	Shaped like the Greek letter delta; triangular with stem attached to side
File:Leaf morphology digitate.png	digitate		whole leaf	A palmately compound leaf with leaflets, similar to palmate
	ecirrate		leaf tip	Without a cirrus; antonym: cirrate
File:Leaf morphology elliptic.png	elliptic		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
File:Leaf morphology apex emarginate.png	emarginate		leaf tip	Slightly indented at the tip
File:Leaf morphology ensiforme.PNG	ensiform		whole leaf	Shaped like a sword; long and narrow with a sharp pointed tip
File:Leaf morphology falcate.png	falcate		whole leaf	Sickle-shaped
File:Leaf morphology Fenestrate.png	fenestrate		leaf surface features	Large openings through the leaf; see perforate; sometimes used to describe leaf epidermal windows
File:Plant morphology solid filiform.png	filiform		whole leaf	Thread- or filament-shaped
File:Leaf morphology flabelate.png	flabellate		whole leaf	Semi-circular or fan-like
File:Leaf morphology hastate.png	hastate		whole leaf or base	Spear-shaped: pointed, with barbs, shaped like a spear point, with flaring pointed lobes at the base
File:Leaf morphology division laciniate.png	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)
File:Leaf morphology lanceolate.png	lanceolate		whole leaf	Long, wider in the middle, shaped like a lance tip
File:Leaf morphology linear.png	linear		whole leaf	Long and very narrow like a blade of grass
File:Leaf morphology lobed.png	lobed		whole leaf	Being divided by clefts; may be pinnately lobed or palmately lobed
File:Leaf morphology Lorate.png	lorate		whole leaf	Having the form of a thong or strap
File:Leaf morphology Lyrate.png	lyrate		whole leaf	Shaped like a lyre, pinnately lobed leaf with an enlarged terminal lobe and smaller lateral lobes. See also List of lyrate plants.
File:Leaf morphology Mucronate.png	mucronate	mucronatus	leaf tip	Ending abruptly in a small sharp point as a continuation of the midrib
File:Leaf morphology multifide.svg	multifid	+	whole leaf	Cleft into many parts or lobes
File:Leaf morphology obcordate.png	obcordate		whole leaf	Heart-shaped, stem attaches at the tapering end
File:Leaf morphology oblanceolate.png	oblanceolate		whole leaf	Much longer than wide and with the widest portion near the tip; reversed lanceolate
File:Leaf morphology oblique.png	oblique		leaf base	Asymmetrical leaf base, with one side lower than the other
File:Leaf morphology oblong.png	oblong		whole leaf	Having an elongated form with slightly parallel sides; roughly rectangular
File:Leaf morphology obovate.png	obovate		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.
File:Leaf morphology obtuse.png	obtuse		leaf tip or base	Blunt, forming an angle > 90°
File:Leaf morphology orbicular.png	orbicular		whole leaf	Circular
File:Leaf morphology ovate.png	ovate		whole leaf	Egg-shaped, with a tapering point and the widest portion near the petiole
File:Leaf morphology palmate.png	palmate		whole leaf	Palm-shaped, i.e. with lobes or leaflets stemming from the leaf base
File:Palmatilobé.svg	palmately lobed		whole leaf	Lobes spread radially from a point
File:Palmatifide.svg	palmatifid	+	whole leaf	Palm-shaped, having lobes with incisions that extend less than halfway toward the petiole
File:Palmatipartite.svg	palmatipartite	+	whole leaf	Having palmate lobes with incisions that extend over halfway toward the petiole
File:Palmatiséquée.svg	palmatisect	+	whole leaf	Having palmate lobes with incisions that extend almost up, but not quite to the petiole.
File:Leaf morphology pandurate.png	pandurate	panduratus	whole leaf	Fiddle-shaped; obovate with a constriction near the middle.
File:Leaf morphology pedate.png	pedate		whole leaf	Palmate, with cleft lobes
File:Leaf morphology peltate.png	peltate		stem attachment	A round leaf where the petiole attaches near the center, e.g. a lotus leaf
File:Leaf morphology attachment connate-perfoliate.png	perfoliate		stem attachment	With the leaf blade surrounding the stem such that the stem appears to pass through the leaf
File:Leaf morphology Perforate.png	perforate		leaf surface features	Many holes, or perforations, on leaf surface. Compare with fenestrate.
File:Pennatilobé.svg	pinnately lobed	+	whole leaf	Having lobes pinnately arranged on the central axis
File:Pennatifide.svg	pinnatifid	+	whole leaf	Having lobes with incisions that extend less than halfway to the midrib
File:Pennatipartite2.svg	pinnatipartite	+	whole leaf	Having lobes with incisions that extend more than halfway to the midrib
File:Pennatiséquée.svg	pinnatisect	+	whole leaf	Having lobes with incisions that extend almost to, or up to, the midrib
File:Leaf morphology reniform.png	reniform		whole leaf	Shaped like a kidney, with an inward curve on one side
File:Leaf morphology apex retuse.png	retuse		leaf tip	With a shallow notch in a round apex
File:Leaf morphology rhomboid.png	rhomboid, rhombic		whole leaf	Diamond-shaped
File:Leaf morphology apex rounded.png	rounded		leaf tip or base	Circular, no distinct point
	semiterete		3-D shape	Rounded on one side and flat on the other
File:Leaf morphology spear-shaped.png	sagittate		whole leaf	Arrowhead-shaped with the lower lobes folded, or curled downward
File:Leaf morphology spatulate.png	spatulate		whole leaf	Spoon-shaped; having a broad flat end which tapers to the base
File:Leaf morphology hastate.png	spear-shaped		whole leaf	See hastate.
File:Leaf morphology subobtuse.png	subobtuse		leaf tip or base	Somewhat blunted; neither blunt nor sharp
File:Leaf morphology subulate.png	subulate		leaf tip	Awl-shaped with a tapering point
File:Plant morphology solid terete.png	terete		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.
File:Leaf morphology trullate.png	trullate		whole leaf	Shaped like a masonry trowel
File:Leaf morphology truncate.png	truncate		leaf tip or base	With a squared-off end
	undulate		3-D shape	Wave-like
File:Leaf morphology unifoliate.png	unifoliate		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.

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	Description
File:Leaf morphology entire.png	entire	Forma integra	Even; with a smooth margin; without toothing
File:Leaf morphology ciliate.png	ciliate	ciliatus	Fringed with hairs
File:Leaf morphology crenate.png	crenate	crenatus	Wavy-toothed; dentate with rounded teeth
	crenulate	crenulatus	Finely crenate
	crisped	crispus	Curly
File:Leaf morphology dentate.png	dentate	dentatus	Toothed; may be coarsely dentate, having large teeth or glandular dentate, having teeth which bear glands
File:Leaf morphology denticulate.png	denticulate	denticulatus	Finely toothed
File:Leaf morphology doubly serrate.png	doubly serrate	duplicato-dentatus	Each tooth bearing smaller teeth
File:Leaf morphology serrate.png	serrate	serratus	Saw-toothed; with asymmetrical teeth pointing forward
File:Leaf morphology serrulate.png	serrulate	serrulatus	Finely serrate
File:Leaf morphology sinuate.png	sinuate	sinuosus	With deep, wave-like indentations; coarsely crenate
File:Leaf morphology lobate.png	lobate	lobatus	Indented, with the indentations not reaching the center
File:Leaf morphology undulate.png	undulate	undulatus	With a wavy edge, shallower than sinuate
File:Leaf morphology spiny.png	spiny or pungent	spiculatus	With stiff, sharp points such as thistles

Leaf folding

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
File:Peperomia dolabriformis.jpg	conduplicate		Folded upwards, with the surfaces close to parallel
File:Mimetes fimbrifolius (5211424654).jpg	cucullate		Forming a hood, margins and tip curved downward
File:Involute vernation.jpg	involute		Rolled upwards (towards the adaxial surface)
File:Palm leaf washingtonia robusta.jpg	plicate	plicatus	With parallel folds
	reduplicate		Folded downwards, with the surfaces close to parallel
File:Ledum groenlandicum.jpg	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', , is neuter. In descriptions of a single leaf, the neuter singular ending of the adjective is used, e.g. 'lanceolate leaf', 'linear leaf'. In descriptions of multiple leaves, the neuter plural is used, e.g. 'linear leaves'. Descriptions commonly refer to the plant using the ablative singular or plural, e.g. 'with ovate leaves'.

See also

• Glossary of botanical terms
• Glossary of plant morphology
• Cladophylls are leaf-like petioles
• Leaf size
• Sinus
• Leaflet (botany) and Rachis
• Petiole (botany) and Plant stem
• Phylloclades are flattened stems that resemble leaves
• Pinnation
• Plant morphology
• Taxonomy (biology)

Bibliography

• Stearn, W.T. (2004). Botanical Latin (4th (p/b) ed.). Portland, Oregon: Timber Press. ISBN 978-0-7153-1643-6.
• "Leaves"., in
• "Shapes"., in
• Massey, Jimmy R.; Murphy, James C. (1996). "Vascular plant systematics". NC Botnet. University of North Carolina at Chapel Hill. Retrieved 19 January 2016.

External links

• The Description of Leaves, University of Rochester
• Fairchild Tropical Botanic Garden
• Vplants
• Botany 115
• The seed site