Facing away from axis or stem, such as the under-surface of an erect leaf in respect to a vertical stem. cf. adaxial.

Margins forming a terminal angle between 45°–90°.

Facing towards the axis or stem, such as the upper surface of an erect leaf in respect to a vertical stem. cf. abaxial.

The final growth phase of the leaves. Adult leaves in e.g. eucalypts occur in mature trees or mallees. They are different from juvenile leaves in at least some of the characteristics such as colour, shape, size, and relationship to each other on the stem. In some eucalypts, adult leaves never or rarely form.

Roots that arise from above-ground stems and trunks, rather than the main axis of the root. E.g. aerial roots.

Fibrous adventitious roots above-ground stems and trunks. Aerial roots can be prominent and extensive on some pōhutukawa (Metrosideros excelsa) trees.

A cluster of fruits derived from a single flower in which the carpels are free, or almost so, from each other.

(1) of leaves or flowers, inserted singly at different levels along the branches (commonly used to include spiral arrangement); (2) between, as in ‘stamens alternate with the petals’. cf. opposite.

The pollen-bearing organ at the apex of the stamen.

Ending in a short, slender, ± flexible point; less abrupt than mucronate.

A secondary or subsidiary part of an organ; a special outgrowth.

Gradually tapering, drawn out.

The angle or space between the stem and a leaf or branch.


The tissues, collectively outermost to the cambium of a woody plant.

A prominent terminal projection, especially of a carpel or fruit.

Of eucalypts, when the operculum is markedly or slightly contracted to form a beak.

Botanically, a fleshy fruit not opening by valves or regular lines, with the seeds immersed in the pulp.

The lamina, or expanded part of a leaf.

A simple inflorescence ending in a vegetative (non-floral) bud in which the main axis bears lateral flowers; includes corymbs, racemes, spikes, and umbels. pl. botryia.

Modified, reduced leaf found in the inflorescence.

Small branches, or divisions of a branch, of trees and usually bearing the leaves; or of flowering branches as in inflorescences.

Much condensed, undeveloped shoots or flowers. In this key, usually referring to the developing flowers.

With the surface blistered or puckered.


The separate or united sepals of one flower collectively. pl. calyces.

A dry dehiscent fruit derived from two or more carpels. Capsules may dehisce in various ways. adj. capsular.

The female reproductive organ of a flower, consisting of an ovary, a stigma, and usually a style. It may occur singly or as one of a group.

Producing flowers and fruits on well-developed trunks or major branches. cf. ramiflorous.

Producing flowers and fruits on well-developed trunks or major branches. adj. cauliflorous. cf. ramiflory

Paper-like in texture.

The long, narrow stalk-like base of a sepal or petal.

Of ± the same colour throughout or on both surfaces, such as in leaves when the upper leaf surface colour is the same as, or very similar to, the lower surface. cf. discolorous.

Cone-shaped, with the broad end at the base.

Young stems shooting from a stump, or the juvenile growth sprouting from mature trunks or branches.

Heart-shaped in outline, with the notch at the base, e.g. of a leaf blade (lamina). cf. obcordate.

The separate or united petals of one flower collectively.

Inflorescence with branches starting at different points but with flowers reaching about the same height. adj. corymbose.

Embryonic leaf or leaves in seed.

With shallow, rounded teeth perpendicular to the margins, such as those of a leaf blade (lamina); diminutive crenulate. cf. dentate.

Finely crenate along the margin. cf. denticulate.

The part of a tree or shrub above the level of the lowest branch.

Contraction of ‘cultivated variety’, a selection developed and maintained in cultivation, distinguished by characters significant for the purposes of agriculture, forestry or horticulture.


A growth habit with branches spreading horizontally but turned up at the ends.

Of leaves or other organs that are opposite with successive pairs at right-angles and so forming four rows.

Of the eucalypt flower bud, when the operculum sheds; of the anther, when the lobes open and shed the pollen; of the fruit, when the capsule splits and sheds the seed.

With sharp teeth perpendicular to the margins, such as those of a leaf blade (lamina); diminutive denticulate. cf. crenate.

Finely toothed along the margin. cf. crenulate.

Coloured differently on the two surfaces, such as in leaves when the upper leaf surface colour is markedly different to the lower surface. cf. concolorous.

A tiny chamber produced by plants that houses arthropods, often formed on the lower surface of leaves, at the juncture of the midrib and the veins.


Oval; shaped like a flattened circle, symmetric and broadest about the middle, e.g. a leaf shape; length:breadth ratio 2.5:1 to 3:2.

Lengthened, stretched out.

With a notch at the apex, usually broad and shallow and of leaves.

In flowering plants embryos form after the fertilization of a female reproductive (egg) cell by pollen.

Having a natural distribution restricted to a particular geographic region. For example, New Zealand endemic species are not found naturally in any other country. cfindigenous.

Having a continuous margin not toothed or dissected; whole or unbranched, such as leaf blade (lamina) margins.

Buds, shoots or flowers borne on the old wood of trees, often applied to shoots arising from dormant buds after injury or fire, such as in eucalypts.

One plant growing on another, using the host for anchorage, but without deriving nourishment from it (i.e. not parasitic). adj. epiphytic.

(1) upright, e.g. the habit of a shrub; (2) ± perpendicular to the point of attachment, e.g. of flowers, leaves, hairs.

Trees of the genus Eucalyptus, the gum trees centred in Australia. Includes two related genera: Angophora and Corymbia.

Not indigenous; introduced from another region or country by accident or design. In the case of New Zealand, usually from another country.


Curved like the blade of a sickle, such as found in some leaf shapes.

A formal group of one or more genera believed to be related phylogenetically, and morphologically separable from other botanical families. cf. genus.

Close clusters or bundle, e.g. tufts of leaves all arising from the same node.

(1) any thread-like body; (2) the typically narrow stalks of stamens, bearing the anthers at the tips.

A tube or cup-shaped structure derived from either fused petals or the fused bases of the sepals, petals (when present), and the stamen filaments, in the latter case then also known as a hypanthium. Present in some Myrtaceae including the eucalypts.

The sexual reproductive structure of angiosperms, usually comprising one or more stamens and pistils, surrounded by a corolla and a calyx.

The seed-bearing structures in angiosperms, formed from the ovary after flowering. In the Myrtaceae, these are fleshy berries or dry capsules.


A taxonomic group of closely related species or a single species without close relatives; closely related genera are grouped into families. pl. genera.

Without surface ornamentation such as hairs, scales or bristles.

A structure, within or on the surface of a plant, with a secretory function. adj. glandular. See oil glands.

With glands.

Blue-green in colour with a whitish bloom, e.g. the juvenile leaves of many eucalypts.

Almost spherical in shape; usually referring to the bud or fruit shape. adj. globular.

Almost spherical in shape; usually referring to the bud or fruit shape.


The general appearance of a plant, including size, shape and growth form.

The external environment in which plants live, e.g. coastal, indigenous forest, lowland.

Outgrowths from the epidermis, each consisting of a single row of cells; may be branched or unbranched.

Herb-like, not woody; usually green and soft in texture.

Plants that can possess juvenile and adult foliage, such as eucalypts.

In eucalypts, usually referring to the operculum shape, where the operculum is long and narrow (much longer than wide). See operculum.

Progeny resulting from the crossing of two parents with different genetic systems, usually of different species.

A tube or cup-shaped structure derived from the fused bases of the sepals, petals (when present), and the stamen filaments. Present in some Myrtaceae including the eucalypts. Also known as a floral tube.


Naturally occurring in an area, but not necessarily confined to it. For example, New Zealand indigenous species can also occur naturally in other countries. cf. endemic.

Any surface covering, e.g. hairs, scales; a collective term for such coverings.

A general term for the arrangement of flowers on a stem of a plant. The stem bearing the flowers may be single or branched.

The growth phase of the leaves between the juvenile and the adult, characteristic of some eucalypts.

The portion of the stem between two successive leaf attachments. cf. node.

Situated inside the margin but close to it, e.g. of veins in the leaves of many Myrtaceae.

Exotic; a species that does not occur naturally in the area where it is growing. cf. endemic.

In the Myrtaceae, dead bark that is persistent, usually hard, thick, widely and deeply furrowed, and impregnated with reddish exudate (kino).


The first-formed leaves, especially when they differ from the adult leaves. In eucalypts, juvenile stems and leaves occur in young plants or in regrowth, e.g. after fire. They are often different in colour and proportions from adult growth.


Ridged like the bottom of a boat.


The expanded portion or blade of a leaf. Can also refer to the expanded upper part of a petal, sepal or bract.

Shaped like the head of a lance or spear, broadest in the lower half and tapering to the tip, e.g. a leaf shape; narrowly ovate (sometimes, and incorrectly, used for narrowly elliptic); length:breadth 9:1 to 2.5:1. cf. oblanceolate.

Leaves that are attached to stem nodes in three different arrangements: alternate, opposite, or whorled.

A photosynthetic and transpiring organ usually green and borne on the stem of a plant; may be reduced or specialised.

A woody climbing or twining plant. cf. mallee, shrub, tree, vine.

Having a liane-like habit.

A woody, usually conspicuous swelling of the stem below or just above the ground, containing embedded vegetative buds for regeneration following crown destruction, e.g. by fire, as in many eucalypts. See mallee.

Very narrowly oblong, with ± parallel margins, e.g. a leaf shape; length:breadth > 9:1.

Chambers of an organ, especially an ovary, fruit or anther. adj. locular.


The main longitudinal vein in a leaf, usually equally distant from both margins.

(1) a growth habit in which many stems arise from a lignotuber, usually applied to eucalypts; (2) of a plant community dominated by mallee eucalypts. Following bushfires, some eucalypts produce the mallee growth habit of multiple slender stems. cf. shrub, tree, liane, vine.

Midvein; the primary vein which runs from the base to the apex of the leaf blade (lamina); usually the most prominent vein, from which arise the secondary or lateral veins.

Midrib; the primary vein which runs from the base to the apex of the leaf blade (lamina), usually the most prominent vein, from which arise the secondary or lateral veins.

Ending abruptly in a short sharp point (a mucro). Often refers to the leaf tip.

A small short sharp point (a mucro) on an obtuse apex.


An introduced plant now freely reproducing in well-established populations.

The point of attachment of leaves on a stem. cf. internode.


Heart-shaped in outline but attached at the narrower pointed end, e.g. a leaf shape. cf. cordate.

The reverse of lanceolate, with the widest part between the middle and the apex, e.g. a leaf shape. cf. lanceolate.

Longer than broad, with parallel margins and rounded ends, e.g. a leaf shape; length:breadth 2.5:1 to 3:2.

Shaped like an upside-down egg, longer than broad, broadest above the middle, rounded at both ends, e.g. a leaf shape; length:breadth 2.5:1 to 3:2.

Margins forming a terminal angle > 90°.

Oil dots; small or minute structures embedded in a leaf or other organ, secreting a volatile oil, mostly visible as small translucent dots (a hand lens is often needed) against a strong light; usually making the organ aromatic when crushed.

In eucalypts, the cap of a flower bud formed by the fusion of the sepals and the petals (when present). This cap splits open at maturity, exposing the reproductive organs. pl. opercula.

Leaves or flowers borne at the same level but on opposite sides of the axis; or when something occurs on the same radius as something else, e.g. anthers opposite sepals; cf. alternate.

± round in outline, with length equal to width. adj. orbiculate.

The seed bearing part of the flower.

Shaped like an egg, broadest below the middle, rounded at both ends, e.g. a leaf shape; length:breadth 2.5:1 to 3:2.


The stalk of a flower, bud or fruit. adj. pedicellate.

The common stalk of a cluster of buds, flowers, or fruit. adj. pedunculate.

Drooping, hanging downwards, e.g. referring to an umbel, fruiting peduncles, branches, leaves or flowers.

Resembling a petal, especially in colour and texture.

In a flower, segments or divisions of the inner whorl of non-fertile parts surrounding the fertile organs, usually soft. In the Myrtaceae, they number 4 or 5 (or when aberrant, numerous, in cultivars selected for that trait), and may be brightly coloured, or inconspicuous, or absent. cf. sepals.

Stalked, of leaves.

The stalk of a leaf. adj. petiolate.

The inner group of modified leaves in a flower forming the female reproductive organs.

Specialised vertical roots produced by some vascular plants that grow in water; the roots contain spongy tissue which enable them to exchange gases with the atmosphere through lenticels in their aerial portions. Unusual in the Myrtaceae but found in Syzygium maire.

Lying flat on the ground.


Flowers and fruits produced behind the current foliage on woody branches formed in previous, but recent, seasons. cf. cauliflorous.

The production of flowers and fruits behind the current foliage on woody branches formed in previous, but recent, seasons. adj. ramiflorous. cf. cauliflory.

Curved outward or downward.

Rolled backwards (and thus often downwards), e.g. of the margins of a leaf.

Extrusive igneous rock with very high silica content.

When long strips of partly shed bark remain in the crown or drape down the trunk.


Outer edge, usually circular and often raised; in Myrtaceae capsules, such as eucalypts, usually referring to the upper edge of the fruit.

Part of the underground axial system of a plant which does not bear leaves and tends to grow downwards or laterally in the soil. See also adventitious roots, aerial roots.


Of a surface when roughed by short protuberances. adj. scabrous; diminutive scaberulous, scabridulous.

Rough to touch.

In eucalypts, a ring scar on the side of a flower bud left by the loss of the outer operculum.

Scaly, covered with small flakes.

All the veins in a leaf other than the primary vein (midrib/midvein).

A young plant. Seedlings often differ significantly from the mature plant in morphology and habit.

The reproductive bodies formed from a fertilised ovule, consisting of a protective coat enclosing the embryo and food reserves.

In a flower, segments or divisions of the outer whorl of non-fertile parts surrounding the fertile organs. In the Myrtaceae, they can number 4 or 5, and may be brightly coloured, or inconspicuous, or absent. cf. petals.

Of a leaf, bud or fruit, lacking a stalk.

A woody plant, lacking a single main trunk, that rarely reaches greater than 3 m in height when fully grown. cf. mallee, tree, liane, vine.

The secondary veins of a leaf.

The basic unit of classification that usually refers to one or several groups of plants or other living organisms, which share common features and/or ancestry, and interbreed and maintain their distinctive identity through successive generations.

The male reproductive parts of a flower, consisting of a stalk (filament) and a pollen-bearing portion (anther). adj. staminate.

Relating to the stamens.

Stamens joined in a ring at their bases.

Sterile stamens, without anthers or with reduced non-functional anthers.

Star-shaped or with several branches radiating from a single point, e.g. a type of hair.

The general term for the above-ground structure of a plant that supports leaves, flowers and fruits.

Pollen-receptive portion of the pistil.

Paired, reduced leaves or leaves further modified to spines or glands at the base of a petiole.

Dead bark that is persistent, long-fibred, thick, furrowed, and often interlaced beneath the surface.

Non-seed bearing part of the pistil between the stigma and ovary.

A taxonomic category, in rank between species and variety. Abbreviated subsp. (referring to 1 subspecies) or subspp. (if referring to more than 1 subspecies).

1 of 2 or more names for the same taxon. Only 1 name is accepted under the International Code of Botanical Nomenclature.


A term used to describe a member of any taxonomic category, e.g. family, genus, species, variety. pl. taxa.

The study of the principles and practices of classification, the establishing and defining of relationships; often used interchangeably with systematics, but strictly taxonomy is only part of systematics.

With colours or shapes arranged in squares to give a chequered appearance, e.g. of bark.

With a ± regularly incised margin.

Large woody plant, usually with a single distinct trunk, that reaches greater than 3 m in height when fully grown. cf. mallee, shrub, liane, vine.

A taxonomic grouping, in rank between family and genus.

With an abruptly transverse edge as if cut off squarely, e.g. of a lamina apex, or base.


flower cluster (inflorescence) sometimes flat-topped, with pedicels arising from a common centre, often umbrella-shaped. adj. umbellate.

Rounded or conical protuberances, often referring to the tip of the operculum. adj. umbonate.

With a rounded or conical protuberance, in eucalypts often referring to the tip of the operculum.

Having a wavy margin, such as a leaf.

Urn- or pitcher-shaped.


Valvar; opening by valves, such as dehiscing fruits; sepals and petals in bud that meet at the edges but do not overlap.

A lid or segment of an anther or capsule which opens or separates at dehiscence. For example, the roof of a eucalypt fruit (gumnut) that splits into usually triangular valves as the seeds are released. adj. valvate, valvar.

Striped or blotched with various colours, usually of leaves. Variegated leaf blades (lamina) are conspicuously marked with two or more colours, that may take the form of spots, mottling, lines, patches, etc. The term does not include features such as the veins or midribs of a leaf being a different colour.

A taxonomic category below that of species (and subspecies if both used); differentiates variable populations with minor morphological distinctions.

Strands of conducting and usually strengthening tissue in leaves or similar structures. See venation.

The pattern or arrangement of veins in a leaf.

A plant with long trailing woody stems that climb over objects and other plants. cf. mallee, shrub, tree, liane.


A plant growing out of place or where it is not wanted; often characterised by high seed production and their ability to colonise disturbed ground quickly.

An arrangement of three or more parts or organs at the same level round an axis. adj. whorled.

Except where otherwise stated, all material on this New Zealand Myrtaceae identification key is subject to Crown copyright, and that material is licensed for use under the Creative Commons Attribution 4.0 International Licence (CC BY 4.0).