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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.

ear

This term is used to refer to the flower spike and seed head of many grasses.

earth

Often used to refer the soil.

earth-up

This is the practice of heaping soil around the stems of potatoes, celery or other plants. Earthing-up potatoes can promote the development of tuber-bearing side shoots, and earthing-up celery excludes the light from the stems for blanching.

earthworms

These are long, round, segmented brown worms (Lumbricus spp.) which burrow in the soil, eating it, and digesting the organic matter, leaving behind worm casts of eliminated soil. Earthworms are beneficial to the soil since they help aerate the soil, and their presence can be an indicator of a healthy soil. The absence of earthworms could indicate compaction, poor drainage, soil toxicity, or possibly the earthworms have been killed by predators which include other types of worm.

earwig

These are insect pests which gnaw plant tissues. Symptoms are tattered holes in petals. Buds and leaves may also be attacked and in severe cases buds may die.

ebenus

Means "ebony black" in Latin.

eburneus

Means "ivory white" in Latin.

echinatus

Means "prickly" in Latin.

ecological niche

This refers to a particular location in an ecosystem where an organism can successfully exist and reproduce.

ecology

The study of ecosystems; the variety of organisms and features that make up a "community" in the environment, especially with regard to the inter-dependence of the constituent species and the affect of pollution and other human influences.

ecosystem

Term referring to the variety of organisms and features that make up a "community" in the environment, especially with regard to the inter-dependence of the constituent species. Ecosystems are affected by climate, biotic (living), and edaphic (soil) factors which interact together to affect the cycling of nutrients in the food chain.

ectotrophic

This refers to a symbiotic relationship between the roots of a plant and a mycorrhizal fungus, where the fungal cells may live within or tangled around the roots of vascular plants. This situation can be mutually beneficial to both plant and fungus, which is therefore a symbiotic relationship.

edging

Can refer to the trimming of the edge of a lawn to keep it tidy; usually done with edging shears. An edging iron is a crescent-shaped tool on a handle used either for edging or turf cutting.

edulis

Means "edible" in Latin.

eelworm

These are microscopic worms which can cause severe damage to bulbs, herbaceous plants and vegetable crops. The control of eelworms is difficult and generally infected plants should be destroyed. The use of healthy plants for propagation, and by avoiding the planting of the same crop on infected soil can limit the impact of eelworms.

effusus

Means "spread out" in Latin.

egg

A non-motile, female gamete.

egg-shaped

With an outer part broader towards the base than the apex, and round-ended.

elatus

Means "tall" in Latin.

electronic leaf

This refers to a device which detects the humidity and presence of water on its surface, and so initiates the automatic application of mist in a mist propagation unit.

elegans

Means "elegant" in Latin.

element

These are chemicals which are in their simplest form. An example is the oxygen element (symbol O) which naturally exists as a gas in the air; the oxygen gas molecules are composed of two oxygen atoms bonded together. There are over a 170 elements of which about 18 elements are used by organisms (macronutrients and micronutrients plus hydrogen and oxygen and carbon) to make the chemical compounds in their tissues.

elephant hawk moth

Foliage of fuchsias is eaten.

elliptic

Longer than wide with the widest part in the centre. (The same as oblong or oval.)

ellipticus

Means "elliptical" in Latin.

Elm gall mite

Leaves develop hard yellow green swellings on upper surface.

elongate

Meaning "lengthened".

elongation

A term that can refer to the lengthening of stems, roots or leaves as the cells divide at the growing tip and cells stretch under turgor pressure. Mature plant tissues are unable to undergo elongation once the cell walls have thickened.

elongatus

Means "lengthened out" in Latin.

emarginate

With a shallow notch at the apex.

emasculate

The act of removing the anthers from a flower before the pollen has been shed. In this way self-pollination can be prevented, and is a technique used by plant breeders to maximise the cross-pollination and hence the genetic variation of the offspring.

embryo

This an immature plantlet which has resulted from the fertilized ovule by the pollen. In angiosperms the embryo can possess seed leaves plus rudimentary stem and roots. Within a seed the embryo can have sufficient food for germination, either in the form of cotyledons or endosperm. In divisions such as the Pteridophyta the embryo is a young, partly developed sporophyte which is a normal diploid spore.

embryo sac

This is the female gametophyte in angiosperms, formed within the ovule.

emergent

When referring to a water plant it is emergent if it has its roots and some of its stem below water, but has most of its stem, leaves and flowers above the water surface.

emulsion

This is a mixture of water and oil-based chemicals. Some pesticides may be applied in an emulsion form to the trunks and branches of shrubs and trees.

endemic

Native to only one country or area.

endocarp

This is the tissue that contains the seed at the centre of a fruit. The endocarp may contain growth inhibitors to prevent the seed germination until the endocarp is washed away or broken down, possibly through digestion by an animal.

endophyte

A plant which lives inside another organism, but is not parasitic upon it.

endosperm

The nutritive tissue in the seeds of angiosperms, which acts as food supply for the embryo plant until the cotyledons have produced the seed leaves to start photosynthesis. Much of the world's food in the form of flour etc from grain crops such as wheat, barley etc originate from the endosperm. Non-endosperm seeds may have large cotyledons which themselves act as a food store.

endotrophic

This refers to the growing of fungal hyphae between and inside the cells of the root cortex. This mycorrhizal fungal association with the roots can aid the absorption of nutrients for the plant.

ensifolius

Means "sword shaped leaves" in Latin.

ensiformus

Means "acute pointed leaves" in Latin.

entire

A smooth leaf margin with no obvious serrations.

entomology

This is the study of insects.

entomophily

This refers to the insect pollination of flowers. In order to attract insects these flowers are often showy, brightly coloured and fragrant.Flowers pollinated by butterflies and moths produce nectar on which the insects feed, whilst also picking up and depositing pollen. Flowers pollinated by bees may produce vast amounts of pollen, since bees collect pollen as a basis for honey production.

environment

Refers to the surroundings of a plant or other organism including physical (abiotic) factors such as the climate, and living (biotic) factors such as other plants and animals.

enzyme

A soluble protein, or protein complex, which catalyses a biochemical reaction. Enzymes therefore enable the conversion of a chemical/s into other chemical/s, and are vital to the living processes in the tissues of organisms. The action of enzymes can be influenced by environmental factors such as temperature.

ephemeral

This refers to a short-lived plant, which completes its life cycle rapidly; germinating, growing, flowering, setting seed and dying within a few months.

epi ...

This is a prefix to a word which generally means "outside" or "on the outside".

epicalyx

A calyx-like structure outside, but close to the true calyx.

epicarp or exocarp

This is the outer skin-like tissue layer of a fruit, which protects the fruit during dispersal.

epicormic shoot

Referring to new shoots arising directly from the trunk or branches of a tree (from dormant or adventitious buds). They may also be called water shoots.

epicotyl

This is the stem-like structure bearing the first true leaves, that rises above the cotyledons. In hypogeal germination where the cotyledons are left below in the soil, the epicotyl is the first visible sign above soil of germination. In epigeal germination the cotyledons appear above the soil on the hypocotyl, and then the epicotyl develops.

epidermis

Outer cell layer of the plant. The epidermis helps to reduce water loss and helps maintain the shape of the tissues. Stomata are openings in the epidermis that allow gaseous exchange to the tissues, mainly in the leaves.

epigeal germination

In epigeal germination the cotyledons appear above the soil on the hypocotyl, and then the epicotyl (a stem-like structure bearing the first true leaves) develops. In hypogeal germination where the cotyledons are left below in the soil, the epicotyl is the first visible sign above soil of germination.

epigynous

Referring to a flower with an inferior ovary (where the ovary is situated below the calyx).

epiphyll

A plant which grows on the leaves of another plant where light and water can be obtained, and are mostly found in humid, tropical rainforests.

epiphyte

Plant growing on another, but not parasitic. The epiphyte gains its water and dissolved minerals via its fleshy leaves and aerial roots, and they are primarily found in humid rainforests. Example epiphytes are bromeliads and some orchids.

Epsom salts

Another name for magnesium sulphate.

equalis

Means "equal" in Latin.

erectus

Means "upright" in Latin.

ericaceous

Refers to members of the Ericaceae family, which generally dislike (lime-hating) alkaline soils and need acidic soils with a pH reading below 6.5. It may also refer to acidic compost which enables the growth of such plants.

ericinus

Means "heath like" in Latin.

erosion

Refers to the removal of soil or other materials by the action of rainfall, running water, frost, wind or other agent. Some observers estimate that half the agricultural soil of countries like Australia and parts of America have been eroded by careless human activity. Plainly, if this situation persists then humans and the eco-system will be placed in an increasingly precarious state. Soil erosion is therefore of prime concern and must be prevented by a variety of means including good cultivation practises. For example, fragile soils should not be exposed without vegetative cover. Other methods are the use of direct drilling, the growing of suitable plants and the effective use of contours and windshelters. Lessons learned from permacultural practises are also important.

escaped plant

Referring to a plant that has "escaped" from a garden and is now growing "in the wild".

esculentus

Means "fit for food" in Latin.

espalier

This is a method of tree or bush training, where the main stem is upright and the side branches are trained out on both sides horizontally in a single plane. In this way it is possible to grow the plant up against a wall or fence and therefore saving space in a garden.

essential amino acids

Refers to amino acids needed by humans that can only be obtained from plants.

ethene or ethylene

This acts as a simple plant hormone which affects the ripening of fruit and abscission of leaves. Ripe fruit may produce ethene which will promote the green fruit to ripen. Ethene is also known as ethylene.

etiolation

Refers to the abnormal type of growth occurring in heavy shade or darkness, particularly the reduction in the amount of chlorophyll, and an exaggerated elongation of the internodes. The light can be deliberately excluded when crops are forced to produce an early crop, such as in rhubarb when long succulent stems are desired. The process of stem elongation is caused by rapid cell division at the top of the stem.

Eucalyptus sucker

Attacks of sap feeding insect stunts the growth of plants.

eukaryotic

Cells containing a membrane around the cell nucleus. Chromosomes are present on which DNA is located. Mitosis and meiosis occurs where the cell nucleus divides and then the cell itself. Mitosis is the process of normal cell duplication during tissue growth, and meiosis results in the halfing of the chromosome number to produce haploid gametes prior to sexual reproduction.

Euonymus scale

Foliage becomes coated with whiteish scales. Heavy infestations cause yellow colouration. Plants lack vigour and die.

europaeus

Means "European" in Latin.

European walnut aphid, Dusky veined walnut aphid

Affects walnut trees where leaves are damaged and sometimes also green fruits by sap-sucking insect pest; the leaves drop, fruit quality worsens.

eutrophic

Refers to an environment containing high levels of nutrients which enable dense growths of plants or other organisms. It may be that such a dense vegetation is prone to diseases and pests.

eutrophication

This can occur in ponds, rivers and lakes when excess nutrients (such as nitrates) are added resulting in algal growth producing an algal bloom. When the nutrients are largely used up, the algae may die and are decomposed by bacteria which can reduce drastically the oxygen level in the water so that fish and other aerobic organisms die (oxygenation, for example by aerating with a waterfall can help relieve this problem).

evaporation

This is the process where liquid water changes into the gaseous water vapour. Any water surface may have evaporation occurring especially in hot, dry, windy climates. Transpiration is a similar process in that plants give off water vapour (usually via stomata) as an aid to the process of water movement through the plant tissues.

evapotranspiration

This refers to the loss of water through transpiration and the evaporation of other water on the plant surface, and possibly the soil.

evergreen

A plant which bears foliage throughout the year (although usually some older leaves are lost regularly). A semi-evergreen plant retains only some leaves or loses older leaves only when the new growth is produced.

everlasting flower

This term might be used to refer to the blooms of certain flowers which, when cut, can be dried and used in dry flower arrangements.

evolution

A theory which holds that organisms which are more suitable for their environment over time survive and reproduce. Through this method of natural selection certain species will have adaptations which help them survive whilst other species may die out. Such adaptations may have come about by useful mutations or be learnt (in animals), and these features may be passed on to the offspring. If breeding groups of organisms are geographically separated or become different in other ways, then populations of distinct species can arise which can no longer produce fertile offspring when cross-breeding.

excapus

Means "stemless" in Latin.

excelsus

Means "very tall" in Latin.

excorticatus

Means "barkless" in Latin.

excrescence

This refers to a projection from the surface of a plant caused by disease, pest or a disorder. An example might be a gall which is an outgrowth from the root, stem, leaf or flower of a plant; this growth of plant tissue can be a response to infestation by a pathogen such as an insect (eg the gall wasp), bacteria or fungi. Another example would be a burr which is a knot or knob in a tree with undifferentiated growth resulting in swirls of woody tissues, which are prized by woodcarvers for their decorative effects.

excretion

This refers to the production of waste products as a result of metabolism by an organism. An example would be the release of ammonia from some plants, or the production of urea by animals.

exfoliating

Peeling off in thin strips. Some trees have bark which peels off in thin strips such as the "paper bark tree".

exiguus

Means "very small" in Latin.

exine

The outer layer of the wall of a spore or pollen grain. The exine is most often patterned in a way that is unique to the particular plant species, and hence this feature can be used to aid the classification of many plants.

exogenous

Developing or emanating from the outside.

exotic

Refers to a plant which has been introduced from overseas, or it may refer to plants with large colourful flowers or foliage. Usually exotic plants require protection from frost.

expetiolate

Without a petiole.

explant

This refers to a tiny section of plant which is carefully prepared in sterile conditions to be used in vegetative tissue culture or micropropagation. The cells undergo rapid division and differentiation in the nutrient solution or agar, resulting in rudimentary roots, stems and leaves.

exserted

This refers to a part of a flower that projects beyond another part.

exstipulate

Without a stipule (ie having no leaf-like structures at the base of the leaf petiole).

extant

This can refer to a plant or other organism which is widely distributed throughout a region.

extensus

Means "wide" in Latin.

extinct

Refers to a plant or other organism that has died out and been lost either from a region, or from the entire planet.

extrafloral

Refers to an organ which is positioned away from a flower.

exudate

This is some substance which is secreted by the tissues of a plant, examples being resin which may be exuded from some trees such as conifers, and gumming from eucalyptus trees (a method of protection against pests and fire). The exudation may occur naturally or it may occur as a result of infection with a pathogen.

eye

The centre of the flower when it is distinct from the remainder, often because of a noticeably different colour. It also refers to an undeveloped growth bud often found on rhizomes and tubers (such as the "eyes" on potatoes).

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