- List of plant morphology terms
Biologists that study
plant morphologyuse a number of different terms to describe plant organs and parts that can be observed with the human eye using no more than a hand held magnifying lens. These terms are used to identify and classify plants.
General plant terms
*Abaxial - located on the side away from the axis.
*Wing - any flat surfaced structure emerging from the side or summit of an organ; seeds, stems.
*Acaulescent - the leaves and inflorescence rise from the ground, appearing to have no stem.
*Acid plant - plants with acid saps, normally due to the production of ammonium salts (malic and
*Acme - the period when the plant or population is at its maximum vigor.
*Actinomorphic - parts of plants that are radially symmetrical in arrangement.
*Arborescent - growing into a
tree-like habit, normally with a single woody stem.
*Ascending - growing uprightly, in an upward direction, heading in the direction of the top.
*Assurgent - growth ascending.
*Branching - dividing into multiple smaller segments.
*Caducous - falling away early.
*Caulescent - with a well developed stem above ground.
*Cespitose - forming dense tufts, normally applied to small plants typically growing into mats, tufts or clumps.
*Creeping - growing along the ground and producing roots at intervals along surface.
Deciduous- falling away after its function is completed.
*Decumbent - growth starts off prostrate and the ends become upright.
*Deflexed - bending downward.
*Determinate growth - Growing for a limited time, floral formation and leaves.
*Dimorphic - of two different forms.
*Ecad - a plant assumed to be adapted to a specific habitat.
*Ecotone - the boundary that separates two plant communities, generally of major rank - trees in woods and grasses in savanna for example.
*Ectogenesis - variation in plants due to conditions out side of the plants.
*Ectoparasite - a parasitic plant that has most of its mass outside of the host, the body and reproductive organs of the plant lives outside of the host.
*Epigeal - living on the surface of the ground. See also terms for seeds.
**Epigean - occurring on the ground.
**Epigeic - plants with stolons on the surface of the ground.
**Epigeous - on the ground. Used for leaf fungus that live on the surface of the leaf.
*Epilithic - growing on the surface of rocks.
*Epiphloedal - growing on the bark of trees.
**Epiphloedic - an organism that grows on the bark of trees.
*Epiphyllous - growing on the leaves. For example, "
Helwingiajaponica" has epiphyllous flowers (ones that form on the leaves). [ [http://www.botany.utoronto.ca/faculty/dickinson/Morphology.html Comparative morphology ] ]
*Epiphyte - growing on another organism but not parasitic. Not growing on the ground.
**Epiphytic - having the nature of an epiphyte.
*Equinoctial - a plants that has flowers that open and close at definite times during the day.
*Erect - having an essentially upright vertical habit or position.
*Escape - plant originally under cultivation that has become wild, garden plant growing in natural areas.
Evergreen- remaining green in the winter or during the normal dormancy period for other plants.
*Eupotamous - living in rivers and streams.
*Euryhaline - normally living in salt water but tolerant of variable salinity rates.
*Eurythermous - tolerant of a wide range of temperature.
*Exclusive species - confined to specific location.
*Exotic - not native to the area or region.
*Exsiccatus - a dried plant, most often used for specimens in a herbarium.
*Lax - non upright, growth not strictly upright or hangs down from the point of origin.
*Parasitic - using another plant as a source of nourishment.
*Precocious - flowering before the leaves emerge.
*Procumbent - growing prostrate or trailing but not rooting at the nodes.
*Prostrate - laying flat on the ground, stems or even flowers in some species.
*Repent - creeping.
*Rosette - cluster of leaves with very short internodes that are crowded together, normally on the soil surface but sometimes higher on the stem.
**Rostellate - like a rosette.
**Rosulate - arranged into a rosette.
*Runner - an elongated, slender branch that roots at the nodes or tip.
*Stolon - A branch that forms near the base of the plant and grows horizontally and roots and produces new plants at the nodes or apex.
**Stoloniferous - plants produce stolons.
*Suffrutescent - somewhat shrubby, or shrubby at the base.
*Virgate - wand-like, slender erect growing stem with many leaves or very short branches.
*Woody - forming secondary growth laterally around the plant so as to form
Duration of individual plant lives are described using these terms:
*Annual - plants that live, reproduce and die in one growing season.
*Biennial - plants that need two growing seasons to complete their life cycle, normally vegetative growth the first year and flowering the second year.
*Herbs - see herbaceous.
*Herbaceous - plants with shoot systems that die back to ground each year- both annual and non-woody perennial plants.
*Herbaceous perennial - non-woody plants that live for more than two years and the shoot system dies back to the soil level each year.
*Woody perennial - true shrubs and trees or some vines with shoot systems that remain alive above the soil surface from one year to the next.
*Monocarpic - plants that live for a number of years then after flowering and seed set die.
*Vernation - the arrangement of leaves, petals or sepals in an unopened bud.
Roots generally do not offer many characters used in plant identification and classification but are important in determining plant duration though in some groups they very important for proper identification including the grasses.
*Adventitious - roots that form from other than the hypocotyl or from another roots. Roots forming on the stem are adventitious.
*Aerial - roots growing in the air.
* Crown - the place where the roots and stem meet, which may or may not be clearly visible. [cite web | url = http://www.fs.fed.us/database/feis/glossary.html | work = Fire Effects Information System | title = glossary ]
*Fibrous - roots are thread-like and normally tough.
*Fleshy - roots are relatively thick and soft, normally made up of storage tissue. Roots are typical long and thick but not thickly rounded in shape.
*Haustorial - specialized roots that invade other plants and absorb nutrients from those plants.
Lignotuber- root tissue that allows plants to regenerate after fire or other damage.
*Primary - roots that develops from the radically of the embryo, normally the first root to emerge from the seed as it germinates.
*Root Hairs - very small, often one cell wide, roots that do most of the water and nutrient absorption.
*Secondary - roots forming off of the primary root, often called branch roots.
*Tap - a primary root that more or less enlarges and grows downward into the soil.
* Tuberous - roots that are thick and soft, with storage tissue. Typically thick round in shape.
*Accessory buds -
*Acrocarpous - produced at the end of a branch.
*Acutangular - a stem that has several longitudinally running ridges with sharp edges.
*Adventitious buds -
*Alternate - buds are staggered on opposite sides of the branch
*Accessory buds -
Bark- the outer layers of woody plants; cork, phloem, and vascular cambium.
*Bud - an immature stem tip, typically an embryonic shoot, ether producing a stem, leaves or flowers.
*Bulb - an underground stem normally with a short basal surface and with thick fleshy leaves.
*Bundle scar -
*Caudex - the hard base produced by herbaceous perennials used to overwinter the plant.
*Caulescent - with a distinctive stem.
*Cladophyll - a flattened stem that is leaf-like and green- used for photosynthesis, normally plants have no or greatly reduced leaves.
*Climbing - typically long stems, that cling to other objects.
*Corm - a compact, upright orientated stem that is bulb-like with hard or fleshy texture and normally covered with papery, thin dry leaves. Most often produced under the soil surface.
*Cuticle - a waxy membrane covering some leaves and roots that is water-tight.
*Decumbent - stems that lay on the ground but have the ends turning upward.
*Dormant - a state of no growth or reduced growth
*Early wood -
*Epidermis - a layer of cells that cover all primary tissue separating them from the outside environment.
*Erect - growing upright.
*Flower bud -
*Fruticose - woody stemmed with a shrub-like habit. Branching near the soil with woody based stems.
*Guard cell -
*Herbaceous - non-woody and dying to the ground at the end of the growing season. Annual plants die, while perennials regrow from from parts on the soil surface or below ground the next growing season.
*Latent buds -
*Internode - spaces between the nodes.
*Late wood -
*Lateral bud -
*Leaf axils - the space created between a leaf and its branch. This is especially pronounced on monocots like bromeliads.
*Leaf bud -
*Leaf scar - the mark left on a branch from the previous location of a bud or leaf.
*Lenticels - lens-shaped or warty patches of parenchymatous tissue on the surface of the stem.
*Node - were leaves and buds are attached to the stem.
*Pith - the spongy tissue at the center of a stem.
**Chambered pith -
**Continuous pith -
**Diaphragmed pith -
*Spine - an adapted leaf that is usually hard and sharp and is used for protection, and occasionally shading of the plant
*Prickle - an extension of the cortex and epidermis that ends with a sharp point.
*Prostrate - growing flat on the soil surface.
*Rhizome - A horizontally orientated, prostrate stem with reduced scale-like leaves, normally growing under ground but also at the soil surface. Also produced by some species that grow in trees or water.
*Rootstock - the underground part of a plant normally referring to a caudex or rhizome.
*Runner - an above ground stem usually rooting and producing new plants at the nodes.
*Scandent - a stem that climbs.
*Stolon - a horizontally growing stem similar to a rhizome, but growing above or along the ground.
*Tendril - a thigmotropic organ which attached a climbing plant to a support
**Leaf - the photosynthetic organ of a plant
**Stem - vascular tissue that provides support for the plant
*Terminal scale bud scar -
*Opposite - buds are arranged in pairs on opposite sides of the branch
*Vascular bundles -
*Verticil - a whorl of leaves or flowers.
**Verticillate - arranged in whorls.
*Whorled - said of a collection of three or more leaves or flowers that arise from the same point.
*Flower bud -
*Leaf bud -
*Mixed - buds that have both embryonic flowers and leaves.
*Reproductive - buds with embryonic flowers.
*Terminal - bud at the tip or end of the stem.
*Vegetative - buds containing embryonic leaves.
Leaf Parts: - A complete leaf is composed of a blade, petiole and stipules and in many plants one or more might be lacking or highly modified.
*Stipules - a pair of outgrowths from the base of the leaf petiole.
*Stipuloid - resembling stipules. Duration of leaves:
*Persistent - Venation:
*Acrodramous - when the veins run parallel to the leaf edge and fuse at the leaf tip.
*Actinodromous - when the main veins of a leaf radiate from the tip of the petiole.
*Vein - the externally visible vascular bundles, found on leafs, petals and other parts.
*Veinlet - a small vein.Leaf Arrangement or
*Whorl - three or more leaves or branches or pedicels arising from the same node.
*Abruptly pinnate - a compound leaf without a terminal leaflet.
Leaf Blade Shape:
*Acicular ("acicularis"): Slender and pointed, needle-like
*Acuminate ("acuminata"): Tapering to a long point
*Aristate ("aristata"): Ending in a stiff, bristle-like point
*Bipinnate ("bipinnata"): Each leaflet also pinnate
*Cordate ("cordata"): Heart-shaped, stem attaches to cleft
*Cuneate ("cuneata"): Triangular, stem attaches to point
*Deltoid ("deltoidea"): Triangular, stem attaches to side
*Digitate ("digitata"): Divided into finger-like lobes
*Elliptic ("elliptica"): Oval, with a short or no point
*Falcate ("falcata"): sickle-shaped
*Flabellate ("flabellata"): Semi-circular, or fan-like
*Hastate ("hastata"): shaped like a spear point, with flaring pointed lobes at the base
*Lance-shaped, lanceolate ("lanceolata"): Long, wider in the middle
*Linear ("linearis"): Long and very narrow
*Lobed ("lobata"): With several points
*Obcordate ("obcordata"): Heart-shaped, stem attaches to tapering point
*Oblanceolate ("oblanceolata"): Top wider than bottom
*Oblong ("oblongus"): Having an elongated form with slightly parallel sides
*Obovate ("obovata"): Teardrop-shaped, stem attaches to tapering point
*Obtuse ("obtusus"): With a blunt tip
*Orbicular ("orbicularis"): Circular
*Ovate ("ovata"): Oval, egg-shaped, with a tapering point
*Palmate ("palmata"): Divided into many lobes
*Pedate ("pedata"): Palmate, with cleft lobes
*Peltate ("peltata"): Rounded, stem underneath
*Perfoliate ("perfoliata"): Stem through the leaves
Pinnate("pinnata"): Two rows of leaflets
**odd-pinnate : pinnate with a terminal leaflet
**paripinnate, even-pinnate : pinnate lacking a terminal leaflet
*Pinnatisect ("pinnatifida"): Cut, but not to the midrib (it would be pinnate then)
*Reniform ("reniformis"): Kidney-shaped
*Rhomboid ("rhomboidalis"): Diamond-shaped
*Round ("rotundifolia"): Circular
*Sagittate ("sagittata"): Arrowhead-shaped
*Spatulate, spathulate ("spathulata"): Spoon-shaped
*Spear-shaped ("hastata"): Pointed, with barbs
Awl-shaped with a tapering point
*Sword-shaped ("ensiformis"): Long, thin, pointed
*Trifoliate, ternate ("trifoliata"): Divided into three leaflets
*Tripinnate ("tripinnata"): Pinnately compound in which each leaflet is itself bipinnate
*Truncate ("truncata"): With a squared off end
*Unifoliate ("unifoliata"): with a single leaf
Leaf Base Shape:
*Semiamplexicaul - the leaf base wraps around the stem, but not completely.
*Leaf Blade Apex:
*Acuminate - narrowing to a point, used for other structures too.
*Acute - with a sharp rather abrupt ending point.
**Acutifolius - with acute leaves.
*Attenuate - tapering gradually to a narrow end.
Leaf Blade Margins:
*Crenulate - with shallow, small rounded teeth.
Epidermis and periderm texture
*Acanceous - being prickly.
*Acantha - a prickle or spine.
*Acanthocarpus - fruits are spiny.
*Acanthocladous - the branches are spiny.
*Aculeate - having a covering of prickles or needle-like growth.
**Aculeolate - having spine-like processes.
*Aden - a gland.
**Adenoid - gland like.
**Adenophore - a stalk that supports a gland.
**Adenophyllous - leaves with glands.
*Arachnoid - having a cobwebby appearance with entangled hairs.
*Bloom - the waxy coating that covers some plants.
*Canescent - with gray pubescence.
*Ciliate - with a fringe of marginal hairs.
*Coriaceouse - with a tough or leathery texture.
*Fimbriate - finely cut into fringes, the edge of a frilly petal or leaf.
*Glabrous - smooth without any pubescences at all.
*Glandular-punctate - covered across the surface with glands.
*Hirsute - with long shaggy hairs, often stiff or bristly to the touch.
*Lanate - with woolly hairs. Thick wool like hairs.
*Verrucose - with a wart surface, with low rounded bumps.
*Villose - covered with fine long hairs that are not matted.
**Villosity - villous indument.
*Accrescent - Growing larger after anthesis, normally used for the calyx.
*Anthesis - the period when the flower is fully open and functional.
*Acephalous - without a head, used for flower styles without a well-developed stigma.
*Androecium - the stamens collectively.
**Basifixed - attached by the base.
**Connective - the part of the stamen joining the anther cells.
**Epipetalous - born on the corolla, often used in reference to stamens attached to the corolla.
**Exserted - sticking out past the corolla, the stamens protrude past the margin of the corolla lip.
**Extrose - opening towards the outside of the flower.
**Gynandrium - combined male & female structure
**Introrse - opening on the inside of the corolla, the stamens are contained within the margins of the petals.
**Monodelphous - stamen filaments united into a tube.
**Poricidal - anthers opening by terminal pores.
**Staminode - a sterile stamen.
***Staminodial - flowers with sterile stamen.
**Syngenesious - the anthers are united into a tube, the filaments are free.
**Translator - a structure uniting the pollinia in "
Asclepiadaceae" and " Orchidaceae".
**Trinucleate - pollen containing three nuclei when shed.
**Valvular - anthers opening by valves or small flaps, e.g. "
**Versatile - anthers pivoting freely on the filament.
*Anther - The distal end of the stamen where
pollenis produced, normally composed of two parts called anther-sacs and pollen-sacs (thecae).
*Bract - The leaf-like or scale-like leafy appendages that are located just below a flower, a flower stalk, or an inflorescence; they usually are reduced in size and sometimes showy or brightly colored.
*Calyx -The whorl of sepals at the base of a flower.
*Carpel -The ovule-producing reproductive organ of a flower, consisting of the stigma, style and ovary.
*Corolla -The whorl of petals of a flower.
*Disk - an enlargement or outgrowth from the receptacle of the flower, located at the center of the flower of various plants. The term is also use as the central area of the head in composites were the tubular flowers are attached.
*Filament - The stalk of a stamen
*Floral axis -
*Floral envelope -
*Fruit - a structure contain all the seeds produced by a single flower.
*Gynoecium - The whorl of carpels. May comprise one (syncarpous) or more (apocarpous) pistils. Each pistil consists of an ovary, style and stigma (female reproductive organs of the flower).
**Apocarpus - The gynoecium comprises more than one pistil.
**Compound pistil -
**Funicle - the stalk that connects the ovule to the placenta.
**Loculus - the cavities located with in a carpel, ovary or anther.
**Simple pistil -
**Syncarpous - The gynoecium comprises one pistil.
*Nectar - a fluid produce by nectaries high in sugar content, used to attract pollinators.
*Nectary - a gland that secrets nectar, most often found in flowers but also produced on other parts of plants too.
*Nectar disk - when the floral disk contains nectar secreting glands, often modified as its main function in some flowers.
*Pedicel - the stem or stalk that holds a single flower in an inflorescence.
*Peduncle - The part of a stem that bears the entire inflorescence, normally having no leaves or the leaves are reduce to bracts. When the flower is solitary, it is the stem or stalk holding the flower.
**Peduncular - referring to or having a peduncle.
**Pedunculate - having a peduncle.
**Achlamydeous - without a perianth.
*Receptacle - the end of the pedicel that joins to the flower were the different parts of the flower are joined together, also called the torus. In
Asteraceaethe top of the pedicel upon which the flowers are joined.
*Capitulum - the flowers are arranged into a head composed of many separate unstalked flowers, the single flowers are called florets and are packed close together. The typical arrangement of flowers in the
*Compound Umbel - is an umbel where each stalk of the main umbel produces another smaller umbel of flowers.
*Corymb - a grouping of flowers where all the flowers are at the same level, the flower stalks of different lengths forming a flat-topped flower cluster.
*Cyme - is a cluster of flowers were the end of each growing point produces a flower. New growth comes from side shoots and the oldest and first flowers to bloom are at the top.
*Single - one flower per stem or the flowers are greatly spread-apart as to appear they do not arise from the same branch.
*Spike - when flowers arising from the main stem are without individual flower stalks. The flowers attach directly to the stem.
* Solitary - same as single, with one flower per stem.
*Raceme - is a flower spike with flowers that have stalks of equal length. The stem tip continues to grow and produce more flowers with the bottom flowers open first and blooming progresses up the stem.
*Panicle - is a raceme with branches and each branch having a smaller raceme of flowers. The terminal bud of each branch continues to grow, producing more side shoots and flowers.
Pedicel- stem holding a one flower in an inflorescences.
*Peduncle - stem holding an inflorescences, or a single flower.
*Umbel - were the flower head has all the flower stalks rising from the same point of the same length, the flower head is rounded like an umbrella or almost circular.
*Verticillaster - a whorled collection of flowers around the stem, the flowers produced in rings at intervals up the stem. As the stem tip continues to grow more whorls of flowers are produced. Typical in
**Verticil - flowers arranged in whorls at the nodes.
Insertion of floral parts
*Wing - term used for the lateral petals of the flowers on species in
*Valvate - meeting along the margins but not overlapping.
Union of flower parts
*Adelphous - the androecium with the stamen filaments partly or completely fused together.
Flower sexualityand presence of floral parts
*Achlamydeous - flower without a perianth.
*Apetalous - a flower without petals.
*Accrescent - said of the calyx when it is persistent and enlarges as the fruit grows and ripens, applied to other structure sometimes.
*Androgymous - used for the inflorescence of "
Carex" when a spike has both staminate and pistillate flowers - the pistillate flowers are normally at the base of the spike.
*Actinomorphic - having a radial symmetry, as in regular flowers.
**Actinomorphy - when the flower parts are arranged with radial symmetry.
*Zygomorphic - one axis of symmetry running down the middle of the flower so the right and left halves reflect each other.
**Zygomorphy - the type of symmetry that most irregular flowers have with the upper half of the flower unlike the lower half. the left and right halves tend to be mirror images of each other.
*Allogamy – cross pollination, when one plant pollinates another plant
*Anemophilous – wind pollinated.
*Autogamy – self-pollination, when the flowers of the same plant pollinate flowers on the same plant or themselves.
*Cantharophilous – beetle pollinated
*Chiropterophilous - bat pollinated.
*Cleistogamous – self-pollination of a flower that does not open.
*Dichogamy – Flowers that cannot pollinate themselves because pollen is produced at a time when the stigmas are not receptive of pollen.
*Entomophilous – insect pollinated.
*Hydrophilous – Water pollinated, pollen is moved in water from one flower to the next.
*Malacophilous – pollinated by snails and slugs.
*Ornithophilous – pollinated by birds.
*Pollination – the movement of pollen from the anther to the stigma.
*Protandrous – when pollen is produced and shed before the carpels are mature.
*Progynous – when the carpels mature before the stamens produce pollen.
*Antipodal cell -
*Coleorhiza -protecting layer of a seed
*Double ferilization -
*Embryo sac -
*Filiform apparatus -
*Plumule -the part of an embryo that give rise to the shoot system of a plant
*Polar nuclei -
Fruits and seeds
Fruits are the matured ovary of seed bearing plants and they include the contents of the ovary, which can be floral parts like the receptacle, involucre, calyx and others that are fused to it. Fruits are often used to identify plant taxa and help to place the species in the correct family or differentiate different groups with in the same family.
Terms for fruits
*Accessory structures - parts of fruits that do not form from the ovary.
*Beak - normally the slender elongated end of a fruit, typically a persistent style-base.
*Circumscissile - a type of fruit dehiscences were the top of the fruit falls away like a lid or covering.
*Dehiscent - the way a fruit openings and releases its contents, normally in a regular and distinctive fashion.
*Endocarp - includes the wall of the seed chamber, the inner part of the pericarp.
*Exocarp - the pericarp's outer part.
*Fleshy - soft and juicy.
*Indehiscent - fruits that do not have specialized structures for opening and releasing the seeds, they remain closed after the seeds ripen and are opened by animals, weathering, fire or other external means.
*Mesocarp - the middle layer of the pericarp.
*Pericarp - the body of the fruit from its outside surface to the chamber were the seeds are, including the outside skin of the fruit and the inside lining of the seed chamber.
*Suture - the seam along which the fruit opens, normally in most fruits it is were the carpel or carpels are fused together.
*Valve - one of the segments of the capsule.
Fruits are divided into different types depending on how they form, were or how they open and what parts they are composed of.
*Achaenocarp - see achene.
*Achene - dry indehiscent fruit, they have one seed and form from a single carpel, the seed is distinct from the fruit wall.
Drupe- outer fleshy part surrounds a shell with a seed inside.
*Utricle - a small inflated fruit with one seed that has thin walls,
*Acrostichoid sorus - having several fused sori.
*Annulus -outer part of sporangium
*Sorus / Sori -
*Acrandrous - used for moss species that have antheridia at the top of the stem.
*Acrocarpous - In mosses, bearing the sporophyte at the axix of the main shoot
*Acrogynous - In liverworts, the female sex organs terminate the main shoot
*Anacrogynous - In liverworts, female sex organs are produced by a lateral cell, thus the growth of the main shoot is indeterminate
*Androgynous - Monoicous, and producing both types of sex organs together.
*Antheridiophore - A specialised branch that bears the antheridia in the Marchantiales
*Archegoniophore - A specialised branch that bears the archaegonia in the Marchantiales
*Autoicous - Produces male and female sex organs on the same plant but on separate inflorescences
*Cladautoicous - Male and female inflorescences on separate branches of the same plant
*Dioicous - Having two forms of gametophyte, one form bearing antheridia and one form bearing archegonia.
*Gonioautoicous - Male is bud-like in the axil of a female branch
*Involucre - A tube of thallus tissue that protects the archegonia
*Monoicous - Having a single form of gametophyte bearing both antheridia and archegonia, either together or on separate branches.
*Paraphyses - Sterile hairs surrounding the archegonia and antheridia
*Perianth - A protective tube that surrounds the archegonia, characterises the Jungermannialean liverworts
*Perichaetium - The cluster of leaves with the enclosed female sex organs
*Perigonium - The cluster of leaves with the enclosed male sex organs
*Pseudautoicous - Dwarf male plants growing on living leaves of female plants
*Pseudoperianth - An involucre that resembles a perianth, but is made of thallus tissue, and usually forms after the sporophyte develops
*Rhizautoicous - Male inflorescence attached to the female stem by rhizoids
*Synoicous - Male and female sex organs on the same gametophyte but are not clustered
*Annulus - in mosses, cells with thick walls along the rim of the sporangium and were the peristome teeth are attached.
*Basal membrane -
*Divisural line -
*Nurse cells -
Glossary of botanical terms
*Jones, Samuel B., and Arlene E. Luchsinger. 1979. "Plant systematics". McGraw-Hill series in organismic biology. New York: McGraw-Hill.
*Usher, George, and George Usher. 1996. "The Wordsworth dictionary of botany". Ware, Hertfordshire: Wordsworth Reference.
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