Terminology

Shapeedit

Edge (margin)edit

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
	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
	Undulate	Undulata	With a wavy edge, shallower than sinuate
	Spiny or pungent	Spiculata	With stiff, sharp points such as thistles

Apex (tip)edit

Image	Term	Latin	Description
	Acuminate	_	Long-pointed, prolonged into a narrow, tapering point in a concave manner
	Acute	_	Ending in a sharp, but not prolonged point
	Cuspidate	_	With a sharp, elongated, rigid tip; tipped with a cusp
	Emarginate	_	Indented, with a shallow notch at the tip
	Mucronate	_	Abruptly tipped with a small short point
	Mucronulate	_	Mucronate, but with a noticeably diminutive spine
	Obcordate	_	Inversely heart-shaped
	Obtuse	_	Rounded or blunt
	Truncate	_	Ending abruptly with a flat end

Baseedit

Acuminate

Coming to a sharp, narrow, prolonged point.

Acute

Coming to a sharp, but not prolonged point.

Auriculate

Ear-shaped.

Cordate

Heart-shaped with the notch towards the stalk.

Cuneate

Wedge-shaped.

Hastate

Shaped like an halberd and with the basal lobes pointing outward.

Oblique

Slanting.

Reniform

Kidney-shaped but rounder and broader than long.

Rounded

Curving shape.

Sagittate

Shaped like an arrowhead and with the acute basal lobes pointing downward.

Truncate

Ending abruptly with a flat end, that looks cut off.

Surfaceedit

The leaf surface is also host to a large variety of microorganisms; in this context it is referred to as the phyllosphere.

Hairinessedit

"Hairs" on plants are properly called trichomes. Leaves can show several degrees of hairiness. The meaning of several of the following terms can overlap.

Arachnoid, or arachnose

With many fine, entangled hairs giving a cobwebby appearance.

Barbellate

With finely barbed hairs (barbellae).

Bearded

With long, stiff hairs.

Bristly

With stiff hair-like prickles.

Canescent

Hoary with dense grayish-white pubescence.

Ciliate

Marginally fringed with short hairs (cilia).

Ciliolate

Minutely ciliate.

Floccose

With flocks of soft, woolly hairs, which tend to rub off.

Glabrescent

Losing hairs with age.

Glabrous

No hairs of any kind present.

Glandular

With a gland at the tip of the hair.

Hirsute

With rather rough or stiff hairs.

Hispid

With rigid, bristly hairs.

Hispidulous

Minutely hispid.

Hoary

With a fine, close grayish-white pubescence.

Lanate, or lanose

With woolly hairs.

Pilose

With soft, clearly separated hairs.

Puberulent, or puberulous

With fine, minute hairs.

Pubescent

With soft, short and erect hairs.

Scabrous, or scabrid

Rough to the touch.

Sericeous

Silky appearance through fine, straight and appressed (lying close and flat) hairs.

Silky

With adpressed, soft and straight pubescence.

Stellate, or stelliform

With star-shaped hairs.

Strigose

With appressed, sharp, straight and stiff hairs.

Tomentose

Densely pubescent with matted, soft white woolly hairs.

Cano-tomentose

Between canescent and tomentose.

Felted-tomentose

Woolly and matted with curly hairs.

Tomentulose

Minutely or only slightly tomentose.

Villous

With long and soft hairs, usually curved.

Woolly

With long, soft and tortuous or matted hairs.

Timingedit

Hysteranthous

Developing after the flowers

Synanthous

Developing at the same time as the flowers

Venationedit

Classificationedit

A number of different classification systems of the patterns of leaf veins (venation or veination) have been described, starting with Ettingshausen (1861), together with many different descriptive terms, and the terminology has been described as "formidable". One of the commonest among these is the Hickey system, originally developed for "dicotyledons" and using a number of Ettingshausen's terms derived from Greek (1973–1979): (see also: Simpson Figure 9.12, p. 468)

Hickey systemedit

1. Pinnate (feather-veined, reticulate, pinnate-netted, penniribbed, penninerved, or penniveined)

The veins arise pinnately (feather like) from a single primary vein (mid-vein) and subdivide into secondary veinlets, known as higher order veins. These, in turn, form a complicated network. This type of venation is typical for (but by no means limited to) "dicotyledons" (non monocotyledon angiosperms). E.g., Ostrya.

There are three subtypes of pinnate venation:

Craspedodromous (Greek: kraspedon - edge, dromos - running)

The major veins reach to the margin of the leaf.

Camptodromous

Major veins extend close to the margin, but bend before they intersect with the margin.

Hyphodromous

All secondary veins are absent, rudimentary or concealed

These in turn have a number of further subtypes such as eucamptodromous, where secondary veins curve near the margin without joining adjacent secondary veins.

2. Parallelodromous (parallel-veined, parallel-ribbed, parallel-nerved, penniparallel, striate)

Two or more primary veins originating beside each other at the leaf base, and running parallel to each other to the apex and then converging there. Commissural veins (small veins) connect the major parallel veins. Typical for most monocotyledons, such as grasses.

The additional terms marginal (primary veins reach the margin), and reticulate (primary veins do not reach the margin) are also used.

3. Campylodromous (campylos - curve)

Several primary veins or branches originating at or close to a single point and running in recurved arches, then converging at apex. E.g. Maianthemum .

4. Acrodromous

Two or more primary or well developed secondary veins in convergent arches towards apex, without basal recurvature as in Campylodromous. May be basal or suprabasal depending on origin, and perfect or imperfect depending on whether they reach to 2/3 of the way to the apex. E.g., Miconia (basal type), Endlicheria (suprabasal type).

5. Actinodromous

Three or more primary veins diverging radially from a single point. E.g., Arcangelisia (basal type), Givotia (suprabasal type).

6. Palinactodromous

Primary veins with one or more points of secondary dichotomous branching beyond the primary divergence, either closely or more distantly spaced. E.g., Platanus.

Types 4–6 may similarly be subclassified as basal (primaries joined at the base of the blade) or suprabasal (diverging above the blade base), and perfect or imperfect, but also flabellate.

At about the same time, Melville (1976) described a system applicable to all Angiosperms and using Latin and English terminology. Melville also had six divisions, based on the order in which veins develop.

Arbuscular (arbuscularis)

Branching repeatedly by regular dichotomy to give rise to a three dimensional bush-like structure consisting of linear segment (2 subclasses)

Flabellate (flabellatus)

Primary veins straight or only slightly curved, diverging from the base in a fan-like manner (4 subclasses)

Palmate (palmatus)

Curved primary veins (3 subclasses)

Pinnate (pinnatus)

Single primary vein, the midrib, along which straight or arching secondary veins are arranged at more or less regular intervals (6 subclasses)

Collimate (collimatus)

Numerous longitudinally parallel primary veins arising from a transverse meristem (5 subclasses)

Conglutinate (conglutinatus)

Derived from fused pinnate leaflets (3 subclasses)

A modified form of the Hickey system was later incorporated into the Smithsonian classification (1999) which proposed seven main types of venation, based on the architecture of the primary veins, adding Flabellate as an additional main type. Further classification was then made on the basis of secondary veins, with 12 further types, such as;

Brochidodromous

Closed form in which the secondaries are joined together in a series of prominent arches, as in Hildegardia.

Craspedodromous

Open form with secondaries terminating at the margin, in toothed leaves, as in Celtis.

Eucamptodromous

Intermediate form with upturned secondaries that gradually diminish apically but inside the margin, and connected by intermediate tertiary veins rather than loops between secondaries, as in Cornus.

Cladodromous

Secondaries freely branching toward the margin, as in Rhus.

terms which had been used as subtypes in the original Hickey system.

Further descriptions included the higher order, or minor veins and the patterns of areoles (see Leaf Architecture Working Group, Figures 28–29).

Flabellate

Several to many equal fine basal veins diverging radially at low angles and branching apically. E.g. Paranomus.

Analyses of vein patterns often fall into consideration of the vein orders, primary vein type, secondary vein type (major veins), and minor vein density. A number of authors have adopted simplified versions of these schemes. At its simplest the primary vein types can be considered in three or four groups depending on the plant divisions being considered;

• pinnate
• palmate
• parallel

where palmate refers to multiple primary veins that radiate from the petiole, as opposed to branching from the central main vein in the pinnate form, and encompasses both of Hickey types 4 and 5, which are preserved as subtypes; e.g., palmate-acrodromous (see National Park Service Leaf Guide).

Palmate, Palmate-netted, palmate-veined, fan-veined

Several main veins of approximately equal size diverge from a common point near the leaf base where the petiole attaches, and radiate toward the edge of the leaf. Palmately veined leaves are often lobed or divided with lobes radiating from the common point. They may vary in the number of primary veins (3 or more), but always radiate from a common point. e.g. most Acer (maples).

Other systemsedit

Alternatively, Simpson uses:

Uninervous

Central midrib with no lateral veins (microphyllous), seen in the non-seed bearing tracheophytes, such as horsetails

Dichotomous

Veins successively branching into equally sized veins from a common point, forming a Y junction, fanning out. Amongst temperate woody plants, Ginkgo biloba is the only species exhibiting dichotomous venation. Also some pteridophytes (ferns).

Parallel

Primary and secondary veins roughly parallel to each other, running the length of the leaf, often connected by short perpendicular links, rather than form networks. In some species, the parallel veins join together at the base and apex, such as needle-type evergreens and grasses. Characteristic of monocotyledons, but exceptions include Arisaema, and as below, under netted.

Netted (reticulate, pinnate)

A prominent midvein with secondary veins branching off along both sides of it. The name derives from the ultimate veinlets which form an interconnecting net like pattern or network. (The primary and secondary venation may be referred to as pinnate, while the net like finer veins are referred to as netted or reticulate); most non-monocot angiosperms, exceptions including Calophyllum. Some monocots have reticulate venation, including Colocasia, Dioscorea and Smilax.

However, these simplified systems allow for further division into multiple subtypes. Simpson, (and others) divides parallel and netted (and some use only these two terms for Angiosperms) on the basis of the number of primary veins (costa) as follows;

Parallel

Penni-parallel (pinnate, pinnate parallel, unicostate parallel)

Single central prominent midrib, secondary veins from this arise perpendicularly to it and run parallel to each other towards the margin or tip, but do not join (anastomose). The term unicostate refers to the prominence of the single midrib (costa) running the length of the leaf from base to apex. e.g. Zingiberales, such as Bananas etc.

Palmate-parallel (multicostate parallel)

Several equally prominent primary veins arising from a single point at the base and running parallel towards tip or margin. The term multicostate refers to having more than one prominent main vein. e.g. "fan" (palmate) palms (Arecaceae)

Multicostate parallel convergent

Mid-veins converge at apex e.g. Bambusa arundinacea = B. bambos (Aracaceae), Eichornia

Multicostate parallel divergent

Mid-veins diverge more or less parallel towards the margin e.g. Borassus (Poaceae), fan palms

Netted (Reticulate)

Pinnately (veined, netted, unicostate reticulate)

Single prominent midrib running from base to apex, secondary veins arising on both sides along the length of the primary midrib, running towards the margin or apex (tip), with a network of smaller veinlets forming a reticulum (mesh or network). e.g. Mangifera, Ficus religiosa, Psidium guajava, Hibiscus rosa-sinensis, Salix alba

Palmately (multicostate reticulate)

More than one primary veins arising from a single point, running from base to apex. e.g. Liquidambar styraciflua This may be further subdivided;

Multicostate convergent

Major veins diverge from origin at base then converge towards the tip. e.g. Zizyphus, Smilax, Cinnamomum

Multicostate divergent

All major veins diverge towards the tip. e.g. Gossypium, Cucurbita, Carica papaya, Ricinus communis

Ternately (ternate-netted)

Three primary veins, as above, e.g. (see) Ceanothus leucodermis, C. tomentosus, Encelia farinosa

These complex systems are not used much in morphological descriptions of taxa, but have usefulness in plant identification, although criticized as being unduly burdened with jargon.

An older, even simpler system, used in some flora uses only two categories, open and closed.

• Open: Higher order veins have free endings among the cells and are more characteristic of non-monocotyledon angiosperms. They are more likely to be associated with leaf shapes that are toothed, lobed or compound. They may be subdivided as;
  • Pinnate (feather-veined) leaves, with a main central vein or rib (midrib), from which the remainder of the vein system arises
  • Palmate, in which three or more main ribs rise together at the base of the leaf, and diverge upward.
  • Dichotomous, as in ferns, where the veins fork repeatedly
• Closed: Higher order veins are connected in loops without ending freely among the cells. These tend to be in leaves with smooth outlines, and are characteristic of monocotyledons.
  • They may be subdivided into whether the veins run parallel, as in grasses, or have other patterns.

Other descriptive termsedit

There are also many other descriptive terms, often with very specialized usage and confined to specific taxonomic groups. The conspicuousness of veins depends on a number of features. These include the width of the veins, their prominence in relation to the lamina surface and the degree of opacity of the surface, which may hide finer veins. In this regard, veins are called obscure and the order of veins that are obscured and whether upper, lower or both surfaces, further specified.

Terms that describe vein prominence include bullate, channelled, flat, guttered, impressed, prominent and recessed (Fig. 6.1 Hawthorne & Lawrence 2013). Veins may show different types of prominence in different areas of the leaf. For instance Pimenta racemosa has a channelled midrib on the upper surfae, but this is prominent on the lower surface.

Describing vein prominence:

Bullate

Surface of leaf raised in a series of domes between the veins on the upper surface, and therefore also with marked depressions. e.g. Rytigynia pauciflora, Vitis vinifera

Channelled (canalicululate)

Veins sunken below the surface, resulting in a rounded channel. Sometimes confused with "guttered" because the channels may function as gutters for rain to run off and allow drying, as in many Melastomataceae. e.g. (see) Pimenta racemosa (Myrtaceae), Clidemia hirta (Melastomataceae).

Guttered

Veins partly prominent, the crest above the leaf lamina surface, but with channels running along each side, like gutters

Impressed

Vein forming raised line or ridge which lies below the plane of the surface which bears it, as if pressed into it, and are often exposed on the lower surface. Tissue near the veins often appears to pucker, giving them a sunken or embossed appearance

Obscure

Veins not visible, or not at all clear; if unspecified, then not visible with the naked eye. e.g. Berberis gagnepainii. In this Berberis, the veins are only obscure on the undersurface.

Prominent

Vein raised above surrounding surface so to be easily felt when stroked with finger. e.g. (see) Pimenta racemosa, Spathiphyllum cannifolium

Recessed

Vein is sunk below the surface, more prominent than surrounding tissues but more sunken in channel than with impressed veins. e.g. Viburnum plicatum.

Describing other features:

Plinervy (plinerved)

More than one main vein (nerve) at the base. Lateral secondary veins branching from a point above the base of the leaf. Usually expressed as a suffix, as in 3-plinerved or triplinerved leaf. In a 3-plinerved (triplinerved) leaf three main veins branch above the base of the lamina (two secondary veins and the main vein) and run essentially parallel subsequently, as in Ceanothus and in Celtis. Similarly, a quintuplinerve (five-veined) leaf has four secondary veins and a main vein. A pattern with 3-7 veins is especially conspicuous in Melastomataceae. The term has also been used in Vaccinieae. The term has been used as synonymous with acrodromous, palmate-acrodromous or suprabasal acrodromous, and is thought to be too broadly defined.

Scalariform

Veins arranged like the rungs of a ladder, particularly higher order veins

Submarginal

Veins running close to leaf margin

Trinerved

2 major basal nerves besides the midrib

Diagrams of venation patternsedit

Image	Term	Description
	Arcuate	Secondary arching toward the apex
	Dichotomous	Veins splitting in two
	Longitudinal	All veins aligned mostly with the midvein
	Parallel	All veins parallel and not intersecting
	Pinnate	Secondary veins borne from midrib
	Reticulate	All veins branching repeatedly, net veined
	Rotate	Veins coming from the center of the leaf and radiating toward the edges
	Transverse	Tertiary veins running perpendicular to axis of main vein, connecting secondary veins

Sizeedit

The terms megaphyll, macrophyll, mesophyll, notophyll, microphyll, nanophyll and leptophyll are used to describe leaf sizes (in descending order), in a classification devised in 1934 by Christen C. Raunkiær and since modified by others.