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Glossary of plant terms

Search our dictionary of 3,300 botanical and plant-related terms – the largest online.
Or browse the descriptions and definitions using the A-Z.

macranthus

Means "large-flowered" in Latin.

macro ...

This is a prefix to a word which generally means "large" or "beyond".

macrobiotic

This can refer to seeds which, under the right conditions, will germinate after being a long time dormant.

macrocarpus

Means "with large fruits" in Latin.

macronutrients

This is an element which is needed by plants in large or significant amounts for healthy growth. The main nutrients include: nitrogen, phosphorus, potassium, sulphur, calcium and magnesium.

maculate

Having spotted or speckled markings.

maculatus

Means "blotched - spotted" in Latin.

maggot

Usually referring to the larvae of flies.

magnesium

This element (symbol Mg) is necessary for chlorophyll production in plants. A lack of magnesium gives rise to a deficiency which may be indicated by a yellowing between the veins of the older leaves. To correct a magnesium deficiency, manure or fertilizer containing magnesium such as a balanced fertilizer can be used which contains proportions of nitrogen, phosphate and potash (NPK) plus other minor nutrients. Magnesium sulphate may be used to counter a magnesium deficiency.

magnesium deficiency

Yellowing develop between leaf veins and margins, in some cases brown or pink colouration between leaves. Others develop raised patches. Older leaves are affected first. With conifers the needles turn yellow.

magnesium sulphate

Another name for sulphate of magnesium and sometimes known as Epsom salts, this may be applied to the soil or in a liquid form to the foliage as a foliar feed to counter signs of magnesium deficiency.

magpie moth

Caterpillars feed on currants and gooseberry fruit from late spring and early summer. They overwinter in cracks in the bark.

Mahonia rust

Bright orange spots develop on upper leaf surface with dark brown spore filled fungal pustules beneath and then fall.

main nutrients

This is an element which is needed by plants in large or significant amounts for healthy growth. Macronutrients include: nitrogen, phosphorus, potassium, sulphur, calcium and magnesium.

major

Means "greater" in Latin.

Malathion

This is an insecticide which is effective against many pests (including aphids, leaf hoppers and red spider mite.) Melathion is poisonous to humans and many other animals. Since it is an organo-phosphorus type chemical care should be used if other chemicals of this group are being used because of the danger of an accumulative effect.

male flower

A flower containing stamens but no ovary.

mallee

This is a name given to a small form of eucalyptus tree, usually with swollen bases to the trunks which enables fire resistance.

mamillate

Formed in the shape of a nipple.

Mancozeb

This is a synthetic fungicide which is used for the control of a number of fungal diseases including downy mildews and potato blight.

Maneb

This is a manganese and sulphur-based inorganic preventive fungicide which is available in combination with carbendazim.

manganese

An element (symbol Mn) which is a micronutrient, needed by plants but only in small quantities. If deficient then the plant will suffer chlorosis of some form plus necrotic areas in spots or lesions. To correct a manganese deficiency, manure or a balanced fertilizer can be used which contains proportions of nitrogen, phosphate and potash (NPK) plus other minor nutrients.

Manganese deficiency

Leaves are very pale between veins. In severe cases the whole leaf may appear 'chlorotic. This deficiency is most common on soils with a pH over 6.5. Young leaves are worst affected.

manure

This is a general term for organic material used for improving the soil structure and nutrient content. Examples are: horse manure (which usually includes some straw), leafmould, mushroom compost, garden compost, and green manure (which is a crop such as clover which is ploughed into the soil while still green). Manure is a type of fertilizer but compared to chemical fertilizers a manure tends to give up its nutrients over a longer period of time, and acts to improve the soil condition. Farmyard manure (FYM) is generally waste from farm animals, often including bedding materials, and needs rotting down before use as a soil conditioner. Manure is a type of fertilizer but compared to chemical fertilizers a manure tends to give up its nutrients over a longer period of time, and acts to improve the soil condition. Farmyard manure (FYM) is generally waste from farm animals, often including bedding materials, and needs rotting down before use as a soil conditioner.

maquis

A type of vegetation composed of tall shrubs and often scattered trees. It may form a dense thicket.

marcescent

This term describes leaves which remain on a plant after they have died.

margin

The outer edge of a leaf.

marginal water plant

Refers to a plant that grows partially submerged in shallow water, or which grows in moist soil at the edge of a pond or lake.

marinus

Means "growing by the sea" in Latin.

maritime climate

Mild weather experienced in coastal regions where extremes of hot and cold temperature are moderated by the ocean.

maritimus

Means "of the sea" in Latin.

marlite

A fertilizer that is made from granulated clay with a high lime content.

marsh

An area sometimes called a "fen", which is waterlogged, never drains and is often low-lying. A "saltmarsh" is a marsh with salty water, usually found in low-lying coastal areas.

marsh spot

Leaf veins yellow, inside the peas are brown cavities.

mat

This may refer to dead organic material in a lawn which forms a layer on the surface of the soil, and may be raked clear to improve the condition of the lawn.

maturate

This is another term for ripening. It may also be used in a general sense for becoming mature.

maze

A labyrinth area in a garden where tall hedges, winding paths and dead-ends hide the exit.

MCPA

A systemic selective herbicide used mainly in gardens for the control of weeds on lawns.

meadow

Permanent grass-land often used for hay and grazing for animals. If the meadow is low-lying and flat near rivers or streams, then it may be subject to occasional flooding, and is often called a "water meadow".

mealy

With a floury texture.

mealy bug

A houseplant and greenhouse pest which sucks out the sap from stems of plants. It has a segmented body which is covered in a waxy substance that appears fluffy. The bug may be brushed off the plant (using a cloth which has been dipped in white spirit), or an insecticide containing dimethoate may be used.

mealy cabbage aphid

Damage occurs from early to late summer. Yellow patches appear on foliage between mid-spring and autumn, waxy grey insects feed on undersides of the leaves and growing tips. Affected leaves become distorted, paled and mottled. Dense colonies can build up rapidly, especially in hot years and go unnoticed on undersides of leaves. Young plants are very vulnerable.

mealy plum aphid

Shoot tips and fruit are invaded by powdery white aphids, these aphids hatch in early spring and colonies build up to damaging level by early summer. They produce large amounts of sticky honeydew, and this encourages a black sooty mould to grow.

mechanical injury

Damage caused to plants through physical mishandling.

Mecoprop

A systemic selective herbicide mainly used in gardens for the control of weeds in lawns.

medicus

Means "medicinal" in Latin.

medium soil

This describes a soil which is well balanced and of a medium consistency ie the best loam for growing plants. Less than two thirds of the sand content is between 0.06 and 0.2mm and less than one third is larger than 0.6mm in diameter.

medius

Means "intermediate" in Latin.

medullaris

Means "pithy" in Latin.

medullary

Spongy or pith-like. "Medullary rays" are radial rays of medullary tissue that may be seen in some woody stems, trunks and branches.

mega ...

This is a prefix to a word which generally means "great" or "bigger".

megasporangium

In a heterosporous plant, this is the structure on the diploid sporophyte generation, within which meiosis takes place to produce the haploid female megaspores that give rise to female gametophytes.

megaspore

In a heterosporous plant, these are the female haploid spores that give rise to female gametophytes. Megaspores are sometimes called macrospores.

megasporophyll

The carpel of flowering plants. In non-flowering plants this is the sporophyte bearing megaspores.

megeratus

Means "very lovely" in Latin.

meiosis

In this cell and nuclear division, the chromosome number is halved, so that in each nucleus of the resulting gametes there is only one set (haploid) of the chromosomes. This is the form of cell division enabling sexual reproduction to take place in eukaryotic cells.

melon cotton aphid

Aphids flock on foliage and flowers, sooty moulds then develop. Early death of blooms can occur.

membrane

Thin sheet of organic material. An example could be the nuclear membrane (of a complex molecular structure) which surrounds the cell nucleus.

membranous

Thin and flexible like a membrane.

Menazon

This is a systemic organophosphorus insecticide which is available in combination with Gamma-BHC for spraying, but it is quite persistent and must not be used on edible crops within three weeks of harvesting.

mentum

A chin-like protuberance in some flowers.

mercurous chloride

This compound has been used to control pests such as cabbage root fly and to control diseases such as onion white rot. However it contains mercury and there are now alternative safer treatments available, especially for edible crops.

mericarp

A 1-seeded portion formed by the splitting up of a many-seeded fruit (called a schizocarp), such as those in the families Geraniaceae and Malvaceae.

meripilus giganteus

Golden brown fungal brackets develop around base of tree in late summer or autumn. Fungus causes root decay so damage may not be apparent.

meristem

A group of cells capable of division to form new tissues.

meristem culture

Micropropagation or the use of meristems in tissue-culture.

mesophyte

A term for terrestrial plants which require water when growing. (A xerophyte is a plant growing in dry conditions and a hydrophyte is a plant growing in water.)

mesosperm

The middle coat of a seed.

metabolism

A collective term for the biochemical processes occurring in the living cells and tissues of an organism.

metaldehyde (meta)

A chemical often used in slug pellets, but it not only kills slugs and snails but is also toxic to birds and pets. The pellets are sometimes coloured and made distasteful to try and discourage other animals from eating them. Alternative controls are pellets containing aluminium sulphate or biological controls.

Methiocarb

A chemical used to kill slugs and snails, leatherjackets, millipedes and woodlice.

methylated spirits

A form of alcohol which is sometimes used for pest control.

metre

A measure of length (m) equivalent to 100cm (centimetre) or 1.094 yards or 39.4 inches.

mice

Can be pests when bulbs, corms and seeds are eaten.

michealmas daisy mite

Flower petals replaced by rosettes of green leaves. Stems are disfigured by brown, rough scars caused by tiny, cream mites living at leaf sheaths and flower buds. Flowers are reduced in size and number and are discoloured.

michealmas daisy wilt

Foliage wilts then wither, plants usually dies.

micro ...

This is a prefix to a word which generally means "small" or "less than".

microbe

This is another term for a micro-organism.

microclimate

Refers to a small area which has a certain range of climate, and which is usually different from the surrounding climate. This may be caused by geographical features such as a nearby mountain range or dominant onshore breeze.

micronutrients

This is an element which is only needed by plants in trace amounts for healthy growth. Trace nutrients include: iron, manganese, copper, boron, zinc, molybdenum, sodium, chlorine and cobalt.

micro-organism

This can refer to a protist, bacterium, virus or any organism that can only be seen with a microscope.

microphyllous

A term for plants with tiny leaves.

microphyllus

Means "small leaved" in Latin.

microphyte

A very small plant.

micropropagation

This is another term for tissue culture.

micropyle

This is the tiny opening in the ovule coating through which the pollen tube enters.

microsporangium

In a heterosporous plant, this is the structure on the diploid sporophyte generation, within which meiosis takes place to produce the haploid male microspores that give rise to male gametophytes.

microspore

In a heterosporous plant, this is a haploid spore that develops into a male gametophyte.

midges

This infection occurs around cracks or splits of caned fruit. When bark is peeled back small 3mm pink or red grubs can be seen. Canes are weakened and become vulnerable to winds in winter time.

midrib

The central main vein on a leaf.

mildew

This is a fungal growth on plants that usually gives a white, dusty appearance, and is commonly caused by damp conditions or possibly very dry conditions. Example diseases are downy mildew and powdery mildew.

mile

A measure of length equivalent to 1760 yds (yards) or 1.609 km (kilometre).

millefollium

Means "thousand-leaved" in Latin.

millimetre

A measure of length (mm) equivalent to 0.1cm (centimetre).

millipede

This is an arthropod animal which is related to centipedes (which have 1 pair of legs per segment). Millipedes have long bodies composed of segments, each bearing 2 pairs of legs. They generally live in soil and leaf debris and feed on rotting plants. They can affect plants in spring, especially roots and seedlings, and if the plants have already been attacked by other pests.

mineral nutrients

Refers to non-organic chemicals needed by organisms for their life processes such as calcium, potassium, phosphorus, magnesium etc which are usually found naturally in compounds making up rocks or in soil particles. Certain minerals are macronutrients and micronutrients absorbed by plant roots and incorporated (synthesised) into their tissue compounds. Animals including humans depend ultimately on plants for their own source of mineral nutrients.

minimus

Means "least - small" in Latin.

mint beetle

Holes are eaten in foliage by a leaf beetle.

mint rust

Disease causing rust spots on leaves and stems of mint.

Mistletoe growth

Leafy, parasitic growths on branches which remain green in winter that grow very slowly and may take years to fruit.

mist propagation

Cuttings can be kept moist and cool by automatically spraying them with water at regular intervals. The frequency of spraying may be determined by a timer or the rate of evaporation. Automatic mist propagation units are available which generate mist in response to signals from an electronic leaf that detects the presence of water. Usually mist propagation is done in spring and summer, and are usually "rooted" on the floor or staging of a greenhouse using sand and peat; the cuttings are then transplanted to their ordinary compost as soon as they are rooted.

mite

A type of small spider, such as the red spider mite which can be a pest on many crops such as tomatoes, cucumbers and carnations.

mitosis

This is the process where the cell nucleus and cell divides to create two identical cells. The chromosomes in the original "parent" cell duplicates and a set of chromosomes is incorporated inside the nucleus of each of the new "daughter" cells. This is the basic form of cell reproduction that gives rise to new tissues in eukaryotic organisms.

mixtus

Means "confused" in Latin.

moisture

Refers generally to the amount of water vapour in the air (humidity) or the amount of water in the soil. Generally free-draining but "moisture-retentive" soils are desired by most growers.

moisture meter

Refers to a gauge that indicates the amount of water available in the soil.

molecule

This is a chemical compound where the smallest unit is composed of more than one atom. A water molecule for example is composed of one oxygen and two hydrogen atoms.

moles

Small burrowing animals which create "molehills" at the exits of their tunnels. They feed on earthworms and other soil organisms, although they do not usually feed directly on plants. They are considered a pest and there are a number of methods to try and get rid of them including putting traps, poison, smoke and vibration in the tunnels.

mollis

Means "soft" in Latin.

molybdenum

An element (symbol Mo) which is a micronutrient, needed by plants but only in small quantities. If deficient then the plant leaves may suffer a deformation called "whiptail" where first the older leaves curl and yellow, and then the younger leaves are affected. To correct a molybdenum deficiency, manure or a balanced fertilizer can be used which contains proportions of nitrogen, phosphate and potash (NPK) plus other minor nutrients.

mono ...

This is a prefix to a word which generally means "one" or "single".

monocarpellary

Refers to a fruit that is derived from 1 carpel.

monocarpic

Flowering and fruiting only once and then dying. (These plants may take several years to reach flowering size.)

monocephalous

Having only 1 flower head.

monocotyledon

Having 1 cotyledon (the first leaf of the embryo plant). Plants belonging to the class Monocotyledonae generally have leaves with parallel venation, such as the grasses and sedges.

monoculture

This refers to the agricultural practise of growing only 1 crop in a large field, such as large fields of wheat.

monoecious

Male and female sex organs are produced separately, but both are on the same plant. Flowering plants have separate male and female flowers on each individual plant. (Dioecious plants bear male and female organs on separate plants.)

monophyllus

Means "one-leaved" in Latin.

monopodial branching

Monopodial' refers to a stem that has no side shoots or laterals. 'Monopodial branching' is where the main apex remains active, the shoots arising from axillary buds remaining clearly lateral.

monotypic

Of a single species or genus.

montanus

Means "of the mountains" in Latin.

montmorillonite

A name given to a type of clay comprising very thin sheets of alumino-silicate. Soils which contain this type of clay hold large amounts of water and therefore is "plastic" (plastic soil) in structure.

morhumus

A term for organic matter which remains on the surface of acid soils, and tends not to be incorporated into the soil structure.

morphology

Referring to the structure of an organism or object.

moschatus

Means "musky" in Latin.

Mosiac virus

Leaf veins are yellowed and puckered. Whole plant becomes stunted. Caused by a virus spread by aphids.

moss

A small greenish plant that is a member of the Musci class.

moss pole

This refers to a pole covered in moss for growing climbing or trailing plants. The moss can be kept moist to provide a natural-looking humid microclimate for the plants.

most leaves

Large oak trees may have 250,000 leaves. A large Cypress tree may have up to 50 million leaf scales.

moth (codllin)

A pest of apples and pears where the grubs feed inside the fruits.

mother plant

Can refer to the plant which provide the seed of a hybrid, or any plant that produces a propagule.

moth (goat or leopard)

A pest of many shrubs and trees, but attacks are only occasional. Large caterpillars feed inside branches and trunks, killing either branches or whole plants.

moth (tortrix)

A pest of apples and other fruits, roses, trees and shrubs where small caterpillars feed on the leaves and spin them together.

motile

Able to move.

Motley dwarf virus

Parsley, carrots and parsnip leaves tinged red, middle leaves are speckled yellow. Plants are twisted and roots stunted.

mottling

Blotches of colour. Mottling on upper leaf surfaces, where rounded yellow areas appear, may be caused by viruses. Mottling of blue areas on the soil surface may be caused by stagnant, waterlogged conditions producing anaerobic conditions where aerobic micro-organisms cannot survive.

mould

A general term for some fungal growths, such as sooty mould.

mound layering

A technique of propagation where the mother plant is cut back early in the growing season to just above the ground, which is then covered by soil. This may produce a number of shoots and roots which grow into the soil; these are removed and grown on as separate plants.

mountain ash blister mite

The foliage develops a white-green blistered appearance.

mucilage

A slimy, gum-like substance; often produced in ducts or canals in the plant.

mucronate

Terminated abruptly by a spiny tip.

mucronatus

Means "with a short sharp point" in Latin.

mulberry bacterial blight

A yellow halo develops all over leaf surface and trees overall vigour is affected.

mulberry canker

Shoots die back due to cankers.

mulch

A layer of organic matter spread on the soil surface to conserve moisture. Other purposes are to give some protection from frosts, to reduce the growth of weeds and to enrich the soil. The layer might be compost, leafmould, bark chippings or straw. The mulch is usually added in spring when the soil contains moisture and as it is warming up. (The mulch should not be added if the soil is dry since it will prevent the water from entering.)

mulching too near plant base

The moist environment created by the mulch causes direct damage to the bark and encourages soil micro-organisms which may attack stems.

mull

This is a humus which forms in alkaline soil conditions, and becomes incorporated into the soil structure.

mullen moth

Caterpillars feed on foliage and flower spikes of various plants.

multi ...

This is a prefix to a word which generally means "many" or "more than 1".

multicellular

Refers to more than one cell.

multifid

Having many lobes.

multiflorus

Means "many flowered" in Latin.

multifoliate

Having many leaves.

multigeneric

Referring to hybrids that have many genera as their parents.

multiple fruit

Refers to a single fruit produced from a number of flowers.

muralis

Means "growing on walls" in Latin.

muriate of potash

This fertilizer is composed of potassium chloride. It should be applied directly to the soil since it can scorch plant leaves.

muricate

Warty or rough.

muscariform

Broom-shaped.

muscosus

Means "moss-like" in Latin.

mushroom compost

This compost is composed of the leftovers from mushroom beds. It can be used as a mulch or it can be dug into the soil as a soil improver and plant food since it will contain nitrogen, phosphates, potash and some micronutrients.

mushrooms

A name for the fruiting body of some fungi. Toadstools are also fungal fruiting bodies (which may be poisonous).

mussel scale

A pest of plums where tiny, mussel shaped scales are plastered on stems.

mutabilis

Means "changeable" in Latin.

mutant

Refers to a plant or section of a plant which has had a genetic change. Horticulturists may refer to mutant plants as 'sports', and plant breeders can exploit these natural occurrences and cultivate them to create new plant varieties.

mutation

When a genetic change occurs as a result of chance or some influence such as a chemical, the resulting new mutant plants or animals may feature new characteristics from the parents. Natural selection acting on such mutants may be a mechanism whereby evolution occurs. Horticulturists may refer to mutant plants as 'sports', and plant breeders can exploit these natural occurrences and cultivate them to create new plant varieties.

mycelium

Refers to the network of fungal hypae (fine threads) which may also give rise to fruiting bodies such as mushrooms.

Myclobutanil

A systemic fungicide used to control a range of fungal diseases.

mycology

This is the study of fungi.

mycoplasma

The smallest free-living organism known. Some mycoplasmas are disease pathogens of plants.

mycoplasma infection

Symptoms vary from host to host. Hosts usually are stunted and distorted.

mycorrhiza

A symbiosis between the roots of a plant and a fungus, where the fungal cells may live within or tangled around the roots of vascular plants. This situation can be mutually beneficial (symbiotic relationship) to both plant and fungus, where the fungus absorbs phosphates and nitrates from the soil and produces vitamins helpful to the plant, while the plant gives up sugar to the fungus.

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