Browse through our gardening glossary. From abiotic and angiosperm to zone and zygomorphic, find definitions for both common and technical terms used by gardeners.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
- Achene
- Achene
Tiny, thin-walled, dry fruit holding a single seed; e.g. sunflower seed or the tiny seed-like specks on a strawberry.
- Acorn
- Acorn
Tough, dry nut on oak trees. Comprised of a single, large, smooth seed and a scaly, cup-shaped base.
- Actinomorphic
- Actinomorphic
See Radial symmetry.
- Adroecium
- Adroecium
Male reproductive part of a flower. It accounts for all the stamens on one flower.
- Adventitious
- Adventitious
Structures that grow in an unusual place; e.g. roots that grow from stems.
- Adventive species
- Adventive species
A non-native species considered locally or temporarily established in the wild. An adventive species differs from a naturalized species in that it does not have the reproductive ability to establish itself in an eco-system long-term over a vast area. However a constant renewal of organisms can sustain an adventive population; escapee cultivated plants are an example.
- Aeration
- Aeration
Water and air penetration of a soil. Also used to describe the process of piercing holes in soil or sod to improve air movement.
- Aerial root
- Aerial root
Roots that develop above ground; e.g. mangrove tree roots.
- Aggregate fruit
- Aggregate fruit
Fruit produced from a single flower with two or more separate ovaries. It may look like a dense cluster of many small fruits; e.g. raspberry, blackberry.
- Algae
- Algae
Green, photosynthetic plants without roots or shoots. Found on tree trunks, soil and in fresh or salt water.
- Alpine plant
- Alpine plant
A plant native to mountains, found at high elevations beyond where most trees naturally grow.
- Alternate leaves
- Alternate leaves
Leaves arranged singly along a stem, placed on one side of the stem and then the other. They are not opposite one another or whorled.
- Amendment
- Amendment
Material added to improve soil quality and structure for improved plant growth. Popular amendments include compost, manure, peat moss, alfalfa pellets and horticultural lime.
- Angiosperm
- Angiosperm
One of two groups of plants (the other being gymnosperms) that reproduce via seeds. Angiosperms are flowering plants with a seed coat. Any plant with a flower is an angiosperm including most broadleaved trees; e.g. maple trees, echinacea and tomatoes.
- Annual
- Annual
Plant that completes its whole life cycle, dies and produces seeds within one growing year; e.g. tomatoes, bell peppers, impatiens and snapdragons.
- Annual ring
- Annual ring
Represents the growth of a tree in a single year, visible in cross section as annual rings. One can determine the age of a tree by counting the annual growth rings .
- Anther
- Anther
Sac-like pollen-bearing structure at the top of the stamen (male flower structure).
- Aphid
- Aphid
Small, soft-bodied insect that sucks sap from new, tender plant growth. It can cause damage and transmit plant diseases.
- Aquatic
- Aquatic
Plant adapted to living partly or fully in salt or fresh water.
- Arboretum
- Arboretum
Site where trees and other plants are cultivated as a living collection for scientific research, education and public enjoyment.
- Aril
- Aril
Specialized seed covering; e.g. the juicy, edible portion of a pomegranate.
- Armed
- Armed
Equipped with thorns, prickles or spines.
- Ascending
- Ascending
Upward growth or orientation.
- Axil
- Axil
Upper angle between the stem and petiole (leaf stalk).
- Bacteria
- Bacteria
Single-celled organism that does not have chlorophyll. Bacteria that cause disease are referred to as pathogens.
- Balanced fertilizer
- Balanced fertilizer
A synthetic or natural fertilizer that has equal amounts of nitrogen (N), phosphorus (P) and potassium (K). In this case "balanced" is a technical term; a balanced fertilizer does not necessarily have all the nutrients a plant needs to be healthy.
- Bark
- Bark
Protective external covering on trunks and branches of a woody plant. It is composed of dead, corky cells.
- Basal cutting
- Basal cutting
Propagation technique where a young, newly emerging shoot is cut at ground level from the parent plant.
- Basal leaves
- Basal leaves
Leaves at the very base of a stem.
- Berry
- Berry
Fleshy fruit formed by a single ovary that has one or more seeds; e.g. banana, currant and tomato.
- Biennial
- Biennial
Flowering plant with a two-year life cycle. A biennial normally only flowers in the second year.
- Biodiversity
- Biodiversity
The diversity or variation in the number of species found within a given area, habitat or ecosystem. Biodiversity is considered an environmental health index: the more species present in an environment, the higher the biodiversity of that environment, the healthier that environment is - the opposite is true too.
- Biological control
- Biological control
Method of pest control where an organism, rather than pesticides, is used to kill pests; e.g. farmers may release ladybugs to attack aphids.
- Bisexual
- Bisexual
A single flower with both male and female organs, also called a perfect flower.
- Blade
- Blade
Broad, flat, typically thin and elongated portion of a leaf, petal or sepal.
- Bloom
- Bloom
See flower.
- Bole
- Bole
The section of a tree trunk below the crown, before the branches begin.
- Botanical insecticide
- Botanical insecticide
Naturally occurring chemicals found in plants that act as insecticides. They can be extracted for use as such. Rotenone is a well-known example.
- Bract
- Bract
Modified leaf typically found beneath a flower or flower cluster. It often differs in appearance from other parts of the flower like the petals and sepals.
- Branch
- Branch
Part of a tree that grows out and reaches away from the trunk.
- Broad
- Broad
Widespread or expansive from side to side.
- Broadleaved tree
- Broadleaved tree
Tree with wide, flat leaves. Always a deciduous tree.
- Bud
- Bud
Modified stem; undeveloped stem, branch, leaf or flower often with protective scales.
- Bulbs
- Bulbs
Modified stem; underground stem that stores food in fleshy, scale-like leaves, allowing a plant to overwinter.
- Bur
- Bur
Barbed fruit that clings like velcro to an animal's fur or people's clothing for increased seed dispersal.
- Calyx
- Calyx
Collective term for all of the sepals on a flower. They are usually green and found beneath the petals.
- Cambium
- Cambium
Layer of cells responsible for producing new cells, resulting in growth in diameter each year. Cambium is also found in the tips of growing shoots and roots.
- Capitulum
- Capitulum
When one flower head is composed of many florets (tiny flowers) on a flattened stem, surrounded by an involucre (whorl) of bracts. It appears to be one flower. This type of flower head is typical of the aster, daisy and sunflower family.
- Capsule
- Capsule
Dry fruit with two or more carpels (female flower reproductive organ), often with thin walls, produced by a compound ovary. The capsule splits open to release seeds at maturity; e.g. poppies, primroses.
- Carbon dioxide
- Carbon dioxide
Gas that is naturally a small part of the earth's atmosphere. It is a human and animal waste product from exhaling. Plants use carbon dioxide with water, sun and minerals from the soil to make food.
- Carpel
- Carpel
A female flower's reproductive organ that produces the ovules and seeds. Each carpel looks like a seed-containing chamber. A flower may have one or several carpels, while each carpel has within it one to several ovules. A single carpel consists of a stigma, style and seed-bearing ovary. A single carpel or a group of fused carpels may also called a pistil.
- Caryopsis
- Caryopsis
Fruit where the seed is fused to and surrounded by the pericarp; e.g. rice.
- Casting
- Casting
Soil-like earthworm droppings produced by digesting soil, microbes and organic matter. Vermicomposting yields nutrient-rich castings for use as a soil amendment.
- Caterpillar
- Caterpillar
Larval stage of a butterfly or a moth; hatched from an egg.
- Catkin
- Catkin
Flower cluster with a scaly-bracted, elongated spike made up of many tiny, unisexual flowers without petals. It can be found on trees like birches, alders and willows.
- Chlorophyll
- Chlorophyll
Green pigment found in the chloroplasts of leaves and stems. It is responsible for capturing light in photosynthesis.
- Chloroplasts
- Chloroplasts
Organelle (tiny organ) found in plant cells. They house chlorophyll.
- Chlorosis
- Chlorosis
Loss or destruction of chlorophyll due to a nutritional imbalance or an onset fungal, bacterial or viral infection.
- Chrysalis
- Chrysalis
A self-built structure that contains a caterpillar at the life stage where it transforms into a butterfly or moth. No feeding is required during this period. A chrysalis is sometimes called a cocoon.
- Ciliate
- Ciliate
Lined with cilia which are tiny finger-like or hair-like projections that can appear fringed; e.g. a leaf margin or the margin of a sepal lined with many tiny hairs may be called ciliate.
- Clasping
- Clasping
Leaf base wrapped partly around the stem.
- Clay
- Clay
Heavy mineral soil created by the chemical weathering of rock. It does not drain easily but can be amended with organic matter to improve texture for planting.
- Clone
- Clone
Offspring produced having identical genetic structure to a "parent" organism. This differs from sexual reproduction, where genetic material from two parents is combined to create a new organism with new genetic material.
- Composite flower
- Composite flower
A type of inflorescence (flower cluster) that appears to be one flower at a glance but is actually many little different types of florets (tiny flowers) upon closer inspection. The many tiny flowers function as a single large flower for reproduction; e.g. sunflowers and daisies.
- Compost
- Compost
A product created from the breakdown of organic matter. Composting occurs in the natural world, but it is also a garden practice where kitchen scraps and garden waste are used to create compost for use as a soil amendment.
- Compound
- Compound
Composed of two or more parts, for example a compound leaf or compound ovary (which has two or more carpels). Another meaning: substances formed by the chemical union of two or more substances.
- Compound fruit
- Compound fruit
A unit composed of more than one fruit, classified into two categories: aggregate fruits (e.g. raspberries) and multiple fruits (e.g. figs).
- Compound leaves
- Compound leaves
Leaf made up of two or more distinct leaf-like structures (called leaflets) joined to a single stem.
- Cone
- Cone
Reproductive structure made of modified leaves. It is usually woody when holding the seeds and a bit more fleshy when bearing pollen. It is typically found on coniferous trees like pine, spruce, cedar and fir.
- Conifer
- Conifer
Trees that bear cones. They are usually evergreen, and most conifer trees have needle-like or scale-like leaves.
- Coniferous
- Coniferous
Refers to cone-bearing trees or a type of forest composed of trees that bear cones.
- Cordate leaves
- Cordate leaves
Heart-shaped leaves with a pointed tip.
- Cork cambium
- Cork cambium
Thin layer of live cells found on the underside of bark. They generate new bark cells.
- Corm
- Corm
Modified stem. Short, enlarged underground stem that stores energy when dormant for an early boost in the next season; e.g. crocus, gladiolus.
- Corolla
- Corolla
Collective term for the petals that are usually conspicuous, coloured and whorled.
- Corona
- Corona
Crown-like, funnel- or trumpet-shaped structure on the corolla (petals )of certain flowers; e.g. daffodils.
- Corymb
- Corymb
Branched inflorescence (flower cluster) that is either flat-topped or rounded. The outer flowers at the lowest point on the stem bloom first.
- Cotyledon
- Cotyledon
Leaf of a developing plant within the seed that stores food for the plant embryo. They are the first leaves to appear as the plant grows and have a different look from the other leaves, though they eventually fall off.
- Creeper
- Creeper
Trailing, prostrate plant. Also refers to a trailing shoot that can form roots at the nodes.
- Cross-pollination
- Cross-pollination
Pollen from the anther (male part) of a flower on one plant lands on the stigma (female part) of a flower on a different plant.
- Crown
- Crown
Upper portion of a tree that includes the branches and leaves.
- Cultivar
- Cultivar
A cultivated plant variety. These are plants with desirable characteristics selected for propagation.
- Cultural Control
- Cultural Control
Controlling disease, insect or weed issues by manipulating the growing environment through cultural practices like adjusting the soil pH, soil fertility, irrigation practices, amount of sunlight, etc.
- Cuneate leaves
- Cuneate leaves
Wedge-shaped leaf. It is wide and flat at the top and tapers toward the base.
- Cup floret
- Cup floret
See disk floret.
- Cuticle
- Cuticle
Outer, protective, waxy layer of a leaf or stem.
- Cyme
- Cyme
Type of inflorescence (flower cluster) where each main stalk ends in a flower. The first flowers to bloom are toward the top and then younger flowers arise from the stem below.
- Deciduous
- Deciduous
Trees or shrubs whose leaves fall off in autumn.
- Dehiscent
- Dehiscent
Abrupt opening of a plant structure at maturity, such as a seed pod or spore.
- Deltoid leaves
- Deltoid leaves
Triangular leaf. It is widest at the base and pointed at the tip.
- Diameter at breast height (DBH)
- Diameter at breast height (DBH)
Measures the size of a tree trunk's diameter at breast height (DBH); standardized at 1.3 metres from the ground.
- Dicotyledon
- Dicotyledon
Plant with an embryo containing two cotyledons (seed leaves). Dicot for short.
- Dioecious
- Dioecious
Plants where the staminate (male) and pistillate (female) flowers are found on separate plants of the same species; also known as unisexual plants; e.g. willow trees.
- Disease
- Disease
Any deviation from regular metabolism that affects the normal development and functioning of the plant which may be caused by varying environmental factors or microorganisms.
- Disk floret
- Disk floret
Small flower with a tube-shaped corolla (petals) that usually makes up the central part of a composite flower head, as seen in the sunflower family. It is sometimes called a cup floret.
- Dissected leaves
- Dissected leaves
Deeply cut leaf with fairly narrow segments where the dip in the segments nearly touches the vein's midrib.
- Dormancy
- Dormancy
When physiological activity slows or stops; e.g. a lawn that goes dormant and looks brown during dry spells.
- Double flower
- Double flower
A flower with many extra petals, giving it a full or dense appearance. The double flower is caused by a genetic mutation that rarely occurs in nature; e.g. double-flowered roses and double-flowered carnations.
- Double-toothed
- Double-toothed
Leaf margin edged with teeth where a small tooth is set within a larger tooth.
- Drainage
- Drainage
Describes how water travels through the soil.
- Drupe
- Drupe
Fleshy fruit from a single carpel (female reproductive organ) that is usually single seeded. The endocarp (innermost part of the fruit) is a stone; e.g. peach or plum.
- Elliptic leaves
- Elliptic leaves
Leaf that is widest at the middle and tapers to a point at the base and tip.
- Embryo
- Embryo
A young plant that is still contained within the seed.
- Emergent
- Emergent
Aquatic plant that grows in water with its lower half submerged while its top portion is above water.
- Endocarp
- Endocarp
Innermost layer of the pericarp. It makes up part of a fruit.
- Entire
- Entire
Leaf with a smooth margin (edge).
- Epiphyte
- Epiphyte
Plant that grows on another plant or structure, often for support, but does not harm the other plant. They mainly receive nutrients from air and water from rain; e.g. mosses and lichens.
- Ericaceous
- Ericaceous
Plants belonging to the botanical family Ericaceae. They require acidic soil to survive; e.g. blueberries, rhododendrons and heathers.
- Eukaryote
- Eukaryote
Any organism with cells that contain organelles and a membrane-bound nucleus; e.g. animals, plants and fungi.
- Evergreen
- Evergreen
Tree that remains green throughout the year. A few leaves are shed at a time, but new needles develop before the old ones are shed; e.g. pine, spruce, fir and cedar.
- Exocarp
- Exocarp
Outermost layer of the pericarp. It makes up part of a fruit.
- Ferns
- Ferns
Vascular green plants with large leaves called fronds. Ferns reproduce via spores instead of flowers and seeds.
- Fertility
- Fertility
The availability of nutrients, water and air in the soil for plant growth. A fertile soil usually contains some organic matter, or humus, holds moisture and is crumbly in texture.
- Fertilizer
- Fertilizer
Substance added to soil to supply nutrients to growing plants.
- Fibrous root
- Fibrous root
Branching root system; roots all similar in size.
- Filament
- Filament
The long, slender stalk of the stamen.
- Flabellate leaves
- Flabellate leaves
Fan-shaped leaves; e.g. ginko tree leaves.
- Floret
- Floret
A small flower, often one of many, which make up a larger inflorescence (flower cluster).
- Flower
- Flower
Modified shoot, which is usually colourful and showy, containing the reproductive structures of a plant.
- Follicle
- Follicle
Simple, dry fruit developed from a single carpel (female reproductive organ) of a single ovary; e.g. milkweed.
- Forcing
- Forcing
Accelerating a plant's growth or maturity by artificially adjusting the light and/or temperature, usually to get the plant to bloom sooner.
- Frond
- Frond
Large, divided leaf of a non-flowering plant; e.g. a fern.
- Frost
- Frost
Covering of very thin ice formed when a hard surface is below the dew point of the surrounding air and lower than the freezing point of water.
- Fruit
- Fruit
Ripened or mature ovary or pistil of a flowering plant.
- Full shade
- Full shade
An area that generally receives about three hours of sun exposure a day or less. This dense shade is typically found on the north side of a building.
- Full sun
- Full sun
An area that receives about six hours or more of direct sun.
- Fungus
- Fungus
Not a true plant; includes mushrooms, toadstools and microscopic, disease-producing organisms. It is incapable of producing its own food, so a mass of white threads (called hyphae) feed on dead and decaying plants to provide nutrition
- Gall
- Gall
Abnormal plant growth such as a bulge on the side of a branch that is caused by parasites, including boring insects, fungi and bacteria.
- Germination
- Germination
Sprouting or emergence of a seed, spore or pollen grain after exposure to particular amounts of moisture, warmth and light .
- Gland
- Gland
Bump, or small indentation that secretes liquids such as nectar or oil.
- Ground cover
- Ground cover
Low-growing plants that form a dense covering over the soil, protecting it from erosion and preventing weed growth. Ground covers are usually aesthetically pleasing.
- Grub
- Grub
Thick, whitish, curved larvae of beetles and other insect species that often feed on lawn roots.
- Guard cell
- Guard cell
Special cells found on the surface of leaves and stems. They are found in pairs surrounding a pore and help regulate the exchange of gases.
- Gymnosperm
- Gymnosperm
One of two groups of plants (gymnosperms and angiosperms) that reproduce via seeds. Gymnosperm plants do not have a seed coat. This group includes coniferous plants; e.g. pine trees.
- Gynoecium
- Gynoecium
Female reproductive part of a flower. It accounts for all the carpels on one flower.
- Habit
- Habit
Growth form or appearance of a plant; e.g. a "weeping" habit means a plant has drooping branches.
- Hardening off
- Hardening off
Gradual process of moving seedlings (or other plants) outdoors for increasingly longer periods to acclimatize them to the temperature and wind outdoors. This is usually done in spring.
- Hardwood
- Hardwood
Wood from a dicot, angiosperm tree in temperate and boreal regions. This includes broadleaved trees like oak, ash or beech .
- Hardy
- Hardy
Plant with an ability to endure frost and winter temperatures without the need for additional protection. It is able to come back year after year.
- Heartwood
- Heartwood
Dead wood at the centre of the tree, which no longer transports sap. It hardens to support the tree, which keeps it strong and upright.
- Heirloom
- Heirloom
Any cultivar that was commonly grown by people in the past (generally before 1951, though there are varying opinions as to when) that are able to produce seeds naturally and that were grown for flavour or aroma rather than for large yields or ease of shipment to meet the commercial growing needs of today.
- Herbaceous
- Herbaceous
Plant that does not have woody tissue. These plants are usually soft to the touch; e.g violets, irises.
- Herbicide
- Herbicide
Substance that kills plants, usually weeds. Some herbicides are selective and are used to kill off unwanted plants only, while others are indiscriminate.
- Hesperidium
- Hesperidium
Fruit with a leathery rind that makes up the ovary wall, e.g. oranges.
- Humus
- Humus
A stable material in soil made from the breakdown of organic matter to the point that it will not break down any further. Humus improves soil texture, fertility and water-holding capacity.
- Hybrid
- Hybrid
Plant-breeding term where two similar specimens are crossed, yet differ in at least one characteristic to produce offspring with mixed or new characteristics.
- Hypanthium
- Hypanthium
Joining of the calyx (sepals) and corolla (petals) to form a cup-like base on a flower; e.g. some roses.
- Imperfect flower
- Imperfect flower
Flowers with the reproductive parts of one sex only--either staminate (male) or pistillate (female).
- Incised leaves
- Incised leaves
Leaf margins that appear irregularly and sharply indented. They have a torn appearance. The segments dip less than halfway down to the midrib, unlike dissected leaves.
- Indigenous species
- Indigenous species
See native species.
- Inflorescence
- Inflorescence
Flower cluster. The arrangement of flowers on a stem with many branches to form a flower cluster.
- Integrated Pest Management (IPM)
- Integrated Pest Management (IPM)
Approach to controlling insect pests and diseases through an understanding of the life cycles of the pests and the plants. It is meant to be an environmentally friendly approach to pest management, where chemical controls are a last resort.
- Introduced species
- Introduced species
Species that are not originally from a given region; non-native.
- Invasive species
- Invasive species
Introduced species that compete for resources and space with the native species of the ecosystem to which they were introduced. They can cause serious harm to an ecosystem by reducing biodiversity.
- Involucre
- Involucre
Whorl or circle of bracts surrounding an inflorescence (flower cluster) such as an umbel or capitulum. They look like and serve the same purpose as the calyx (sepals) on a single flower.
- Irregular flower
- Irregular flower
Flower with petals that are variable in shape, not uniform; e.g. violets.
- Keel
- Keel
Sharp ridge or rib-like structure at the base of two lower fused petals of a flower in the pea family. It appears boat-like; e.g. garden pea flowers.
- Lanceolate leaves
- Lanceolate leaves
Lance-shaped leaf; longer than wide, tapered at both ends with the widest part closest to the base.
- Larvae
- Larvae
A juvenile phase in the life cycle of many animals such as insects and amphibians. Larvae often look very different from the adult organism.
- LD50
- LD50
Measure of toxicity. It describes the lethal dose required to kill 50 per cent of a test population of organisms. It is measured in mg/kg of body weight.
- Leaf base
- Leaf base
The bottom part of the leaf blade. The end that is attached to the rest of the plant.
- Leaf margin
- Leaf margin
Edge or perimeter of a leaf.
- Leaf tip
- Leaf tip
The top portion of the leaf blade.
- Leaflet
- Leaflet
Leaf-like section on a compound leaf.
- leafstalk
- leafstalk
Connects leaf blade to main stem of a plant. Also known as the petiole.
- Legume
- Legume
Dry fruit from a single ovary. Usually splits along two lines; e.g. pea pods.
- Lenticel
- Lenticel
Subtly raised pore on bark that allows for gas exchange; e.g. the dark, slot-like lines on light coloured birch bark.
- Lichens
- Lichens
Lichens are composed of a fungus and an algae that live together in a way that benefits both. They grow on rocks, soil, man-made structures and trees.
- Limb
- Limb
Large tree branch.
- Linear leaves
- Linear leaves
Long, thin, strip-like leaves.
- Lip petal
- Lip petal
Enlarged petal on the lower half of some flowers; e.g. orchids.
- Loam
- Loam
Soil type consisting of fine clay, medium silt and coarse sand. It is ideal for planting.
- Lobed
- Lobed
Leaf margin with deep, rounded indentations that are too big to be considered toothed. It has a sinuous appearance.
- Mesocarp
- Mesocarp
Middle layer of the pericarp. It makes up part of a fruit.
- Microorganism
- Microorganism
Organism too small to see with the naked eye. A microscope is required to view it; e.g. bacteria, fungi and protozoa.
- Midrib
- Midrib
Central vein that runs the length of a leaf blade.
- Modified stem
- Modified stem
This stem looks and grows differently from a conventional stem but has similar tissues. Often a plant with a modified stem will have a regular stem as well.
- Monocotyledon
- Monocotyledon
A plant with an embryo containing one cotyledon (seed leaf). Monocot for short.
- Monoculture
- Monoculture
Growing only one crop plant over a large area; e.g. corn and wheat fields or lawns. Monocultures are susceptible to insect pests and diseases because they do not have the diversity of a regular ecosystem.
- Monoecious
- Monoecious
Having both male and female parts on the same plant but found on separate flowers.
- Moss
- Moss
Small plant without flowers or seeds that reproduces via spore capsules. Moss grows closely together forming a soft mat.
- Mould
- Mould
Not a true plant, but rather a microscopic fungus.
- Mulch
- Mulch
Material spread over the soil to shield it from temperature changes, water loss, erosion and weed growth. Examples of organic mulches include wood chips, straw, compost and leaves.
- Multiple fruit
- Multiple fruit
Fruit formed from several clustered flowers, where the ovaries basically fuse together. It is actually many fruits fused together; e.g. pineapples and figs.
- Mycorrhiza
- Mycorrhiza
Beneficial relationship between fungi and the roots of the plants they grow on. This relationship is important for soil chemistry.
- N:P:K
- N:P:K
Abbreviation representing the ratio of three major nutrients--nitrogen (N), phosphorus (P)and potassium (K)--which are often indicated on the packaging of commercial fertilizers.
- Native species
- Native species
A species that has lived and evolved in a specific area or habitat for hundreds of years or more and is considered an original, non-disruptive organism of the ecosystem it lives in; may be referred to as an indigenous species.
- Naturalized species
- Naturalized species
A non-native species that is introduced to a wild area, where it successfully establishes a population. A naturalized species may become invasive if the population grows large enough and has negative effects on the native ecosystem. The term "naturalized" is sometimes used to describe a species that was introduced to an area but that does not disrupt the native ecosystem.
- Nectar
- Nectar
Sugary liquid produced by flowering plants in a small nectar-secreting gland found within a flower.
- Needles
- Needles
Needle-like modified leaves of coniferous trees; e.g. pine needles.
- Nematodes
- Nematodes
Small roundworms that live in the soil as well as many other ecosystems. Some soil-dwelling species are beneficial as they attack lawn-eating grubs.
- Node
- Node
Places on a stem where leaves or branches originate.
- Non-native species
- Non-native species
A species that is introduced to a new area or habitat outside of its natural range. Most non-native species are introduced through human activity. A non-native species may or may not harm the ecosystem to which it is introduced. It may also be referred to as an alien or exotic species.
- Non-vascular plant
- Non-vascular plant
A plant that lacks a complex vascular system. Unlike vascular plants, they do not contain the tissues xylem and phloem, which circulate water and nutrients; e.g. mosses, algae and liverworts.
- Nucleus
- Nucleus
An organelle responsible for controlling all of a eukaryotic cell's activities. It also contains most of the cell's genetic material or DNA.
- Nut
- Nut
Fruit consisting of a hard or toughened shell with a seed that opens in a specific way once it has reached maturity; e.g. hazelnut.
- Obcordate leaf
- Obcordate leaf
Heart-shaped leaf with a pointed base.
- Oblanceolate leaf
- Oblanceolate leaf
Lance-shaped leaf that is longer than wide. It tapers at both ends, with the widest portion closest to the tip.
- Oblong leaf
- Oblong leaf
Rectangular-shaped leaf with rounded corners.
- Obovate leaf
- Obovate leaf
Leaf that is widest at the top and tapers toward the base.
- Opposite leaves
- Opposite leaves
Leaves that grow in pairs from the same point on either side of the stem.
- Organelle
- Organelle
Specific part of a cell that performs a specialized function. An organ is to a body what an organelle is to a cell.
- Organic
- Organic
A natural, earth-friendly gardening style where synthetic substances are not used. When produce is yielded from this type of gardening, it is said to be organic. In the field of chemistry, any compound with carbon atoms is considered organic.
- Organic fertilizer
- Organic fertilizer
Fertilizer derived from a plant or animal--something that was once living.
- Organic matter
- Organic matter
Material from a source that was once alive.
- Ovary
- Ovary
Swollen base of the pistil which develops into a fruit.
- Ovate leaf
- Ovate leaf
Egg-shaped leaf that is wider at the base, with a rounded tip.
- Ovule
- Ovule
Seed before fertilization. The immature ovule is found in the ovary and contains the egg.
- Palmately compound
- Palmately compound
More than three leaflets are directly on the petiole. The leaflets fan out similar to fingers on a hand.
- Palmately lobed
- Palmately lobed
Leaves with three or more divisions or lobes radiating from a common point.
- Panicle
- Panicle
Branched groups of flowers, where each branch is a raceme.
- Pappus
- Pappus
Modified calyx (sepal). It is a bristle or scale on seed-like fruits of the sunflower/aster/daisy family.
- Parasite
- Parasite
Organism that acquires its nutritional needs by taking them from another organism.
- Part shade
- Part shade
An area that receives about three to six hours of sunlight each day.
- Pathogen
- Pathogen
Disease-creating organism.
- Peat moss
- Peat moss
Sold as a soil amendment, it is partly decomposed plants found in peat bogs that are harvested and dried.
- Pedicel
- Pedicel
Stalk or stem of a single flower within an inflorescence (flower cluster).
- Pepo
- Pepo
Fruit where a hard rind makes up the ovary wall; e.g. watermelon.
- Perennial
- Perennial
Plant with a life span greater than two years.
- Perfect flower
- Perfect flower
Single flower with both male and female reproductive parts. Also known as a bisexual flower.
- Perfoliate
- Perfoliate
Leaf base that wraps entirely around the stem. It appears as though the stem punctures through the leaf.
- Perianth
- Perianth
Collective term for petals and sepals.
- Pericarp
- Pericarp
Fruit wall arising from the ovary wall. It is composed of three layers known as the exocarp, mesocarp and endocarp. In berries and drupes the pericarp is the edible part of the fruit.
- Pesticides
- Pesticides
Substance used to regulate, eliminate or repel an unwanted organism.
- Petal
- Petal
This colourful flower part collectively makes up the corolla. Petals are often broad, somewhat flattened and brightly coloured.
- Petiole
- Petiole
Stalk of a leaf. It links the leaf to the stem.
- pH (Power of hydrogen)
- pH (Power of hydrogen)
Measure of acidity or alkalinity of a substance. The pH scale is from 1 to 14, where 1 to 6 is acidic, 7 is neutral, and 8 to 14 is basic or alkaline.
- Phloem
- Phloem
Tissue that circulates food and nutrients produced by the leaves to the rest of a plant.
- Photosynthesis
- Photosynthesis
Process by which a plant makes food for itself. The chlorophyll in leaves uses light to convert carbon dioxide and water into sugars and oxygen.
- Pinching back
- Pinching back
Cutting back a small portion of a branch or stem to encourage bushier, fuller growth on a plant.
- Pinna
- Pinna
The individual leaf-like structures on a leaflet.
- Pinnately compound
- Pinnately compound
Type of leaflet where the pinna (individual leaf-like structures on a leaflet) are lined up in two rows along both sides of a common, central stalk. It has a similar appearance to a feather.
- Pinnately lobed
- Pinnately lobed
Leaves with lobes extending from both sides of the midrib; e.g. oak leaf.
- Pistil
- Pistil
Female part of a flower. A collective term for the stigma, style, ovary and ovules. Also called a carpel.
- Pistillate flower
- Pistillate flower
Female flower that bears the female reproductive structures.
- Pod
- Pod
Dry fruit that opens along two edges at maturity; e.g. pea pod.
- Pollen
- Pollen
Tiny grains formed in the anthers that produce the male reproductive cells. Pollen typically looks yellow and powdery.
- Pollen sac
- Pollen sac
Top portion of the stamen, which contains the pollen grains. Also known as the anther.
- Pollination
- Pollination
Transfer of pollen from the anther to the stigma. This is one of the first steps in fertilization.
- Pollinators
- Pollinators
Animals that transport pollen--mainly insects, but also bats, birds and even some mammals.
- Pome
- Pome
Has many seeds and carpels. The outer half of the pericarp is fleshy, whereas the inner part is paper-like; e.g. apple.
- Prickles
- Prickles
Short, woody, sharp structures found on stems, leaves and even fruits. Prickles are shorter than thorns.
- Prokaryote
- Prokaryote
Any organism with DNA not contained by a membrane within the cells. Prokaryotes lack a cell nucleus unlike a eukaryote; e.g. bacteria.
- Propagation
- Propagation
Reproduction of plants via seeds or spores (sexual propagation) or cells, tissues or organs (asexual reproduction). This term is often used when reproduction is intentional or human-guided.
- Prostrate
- Prostrate
Plant that grows flat along the ground.
- Pupa
- Pupa
Life stage of a holometabolous insect (an insect that undergoes a complete metamorphosis: embryo, larvae, pupa, adult). During the pupa stage, the larval bodies break down and take on the adult body shape.
- Raceme
- Raceme
Long central stalk with a cluster of flowers along the top portion. Each individual flower has a stalk of its own, attached to the larger, shared central stalk.
- Radial symmetry
- Radial symmetry
Implies symmetry (proportion) along multiple axes from a middle point for flowers or any other organism with a wheel-like arrangement; e.g daisy.
- Ray floret
- Ray floret
A small flower with a strap-shaped corolla. They are usually found along the edge of the head of a composite flower. A ray floret is sometimes called a strap floret.
- Receptacle
- Receptacle
Enlarged area at the end of the pedicel where flower parts are joined.
- Reniform leaves
- Reniform leaves
Kidney-shaped leaves.
- Rhizome
- Rhizome
Modified stem. It is a horizontal, underground stem.
- Roots
- Roots
Grows in a downward direction into the ground. Roots uptake water and nutrients.
- Rosette
- Rosette
Modified stem. Ring-shaped group of leaves that radiate from a central point at or near bottom of a stem; e.g. dandelion leaves.
- Round toothed
- Round toothed
Leaf margin with teeth that are rounded rather than pointed.
- Runner
- Runner
Stem that grows horizontally along the soil's surface.
- Samara
- Samara
Fruit that somewhat resembles a wing; e.g. fruit from a maple tree.
- Sandy soil
- Sandy soil
Soil type that is well drained and nutrient poor. It has more than 70 per cent sand particles and less than 15 per cent clay.
- Sap
- Sap
Liquid food and water supply that is transported throughout a tree.
- Saprophyte
- Saprophyte
Plant without chlorophyll that cannot photosynthesize, which means it cannot make its own food. It derives nutrition from dead organic matter.
- Sapwood
- Sapwood
Woody rings of a tree responsible for the transport of water and minerals. It is usually distinguishable from heartwood (dead wood) by its lighter colour in the cross section.
- Scale
- Scale
Parasitic insect that is generally small, often with a waxy-coated body. It uptakes plant juices through a sucking action.
- Scale-like
- Scale-like
Appearance like a fish's skin with small thin, overlying flaps.
- Schizocarp
- Schizocarp
Fruit with two or more united carpels that spilt apart once mature; e.g. carrots.
- Seed
- Seed
In botany it is a mature ovule. In general terms it is a grain that can be planted that will develop into another plant.
- Self-pollination
- Self-pollination
Pollen from the anther of one flower lands on the stigma of the same flower or another flower from the same plant.
- Sepal
- Sepal
Individual unit of the calyx that is usually found beneath the corolla (petals); often green and petal-like or blade-like in appearance.
- Serrate leaves
- Serrate leaves
Sometimes called toothed leaves, they have a margin similar in appearance to the edge of a serrated knife.
- Sessile
- Sessile
Leaf or flower head lacking a stalk.
- Shrub
- Shrub
Woody plant with multiple stems arising from or near the ground. It is shorter in height than a tree.
- Sidedressing
- Sidedressing
Method of applying fertilizer, placing it on either side of a plant.
- Silique
- Silique
Fruit where the carpels separate at maturity leaving behind dividing walls, e.g. mustard.
- Silt
- Silt
Soil type with medium-sized particles, larger than clay but smaller than sand.
- Simple fruit
- Simple fruit
Fruit developed from one flower's single ovary; e.g. apples, plums, watermelons, oranges, peas.
- Simple leaf
- Simple leaf
Leaf with a blade that is not divided.
- Single flower
- Single flower
One flower on one stalk; e.g. tulip.
- Sod
- Sod
Strips of living grass that can easily be laid down to create a lawn.
- Softwood
- Softwood
Wood from gymnosperm trees. Mainly coniferous trees.
- Solarization
- Solarization
Chemical-free method of killing weeds and pathogens. Plastic covering is used across the soil�s surface, and it is left exposed to sunlight for four to six weeks during a hot period.
- Spadix
- Spadix
Spike inflorescence (flower cluster) with tiny flowers on a fleshy stem often enclosed by a colourful leaf-like structure called a spathe; e.g. calla lilies.
- Spathe
- Spathe
A type of bract. It is leaf-like in appearance and may be colourful, which helps attract pollinators to the spadix it encloses.
- Spatulate leaves
- Spatulate leaves
Wide, round-tipped leaves that narrow as they curve at the base.
- Species
- Species
A category of individuals with many shared characteristics. A species is just one category in a classification system used by scientists to group organisms.
- Spike
- Spike
Elongated flower cluster, where each flower is sessile (not attached by a stalk).
- Spiral leaves
- Spiral leaves
See whorled leaves.
- Spores
- Spores
Tiny reproductive cell of a non-flowering plant; e.g. ferns and fungi can reproduce via spores.
- Stamen
- Stamen
Collective term for the male reproductive part of a flower, which consists of the anther (which contains pollen) and the filament.
- Staminate flower
- Staminate flower
Male flower that bears the male reproductive structures.
- Stem
- Stem
Main portion of a plant, which supports the leaves, branches, flowers and fruit. Whether this stem grows above ground or below ground, it is the part that grows in an upward direction, as opposed to the root system, which grows in a downward direction.
- Stigma
- Stigma
Top of pistil where pollen adheres.
- Stipule
- Stipule
Leaf-like structure found at the leaf base or at the base of the petiole on some plants.
- Stolon
- Stolon
Modified stem. Stem that grows at or under the soil's surface.
- Stoma
- Stoma
Pore-like structures on a leaf's surface surrounded by two guard cells that can open and close to allow for gas exchange. The plural of stoma is stomata.
- Strap floret
- Strap floret
See ray floret.
- Stress
- Stress
When a plant is subjected to potentially harmful growing conditions; e.g. too much or too little water, inadequate soil fertility or exposure to pests.
- Style
- Style
Narrow part of the pistil between the stigma (at the top) and the ovary (at the base).
- Succulent
- Succulent
Plant with fleshy leaves or stems that store water; e.g. aloe vera, jade plant.
- Sucker
- Sucker
Adventitious shoot growing from roots or the lower part of a shrub or tree.
- Taproot
- Taproot
Main, downward-growing root of a tree. Also a type of thick, carrot-shaped root that grows straight downward; e.g. dandelions.
- Teeth
- Teeth
Pointy or rounded tabs along a leaf margin. Also see toothed.
- Tendril
- Tendril
Modified leaf, stem or petiole; a thin, coiling structure that helps support climbing plants.
- Tepal
- Tepal
Term for petals and sepals collectively when they are the same in appearance; e.g. tulips and lilies.
- Thatch
- Thatch
Layer of dead and living stems, roots and other debris that accumulate above ground around the base of a lawn of grass.
- Thorns
- Thorns
Sharp, needle-like modified stems; e.g. hawthorns.
- Tillers
- Tillers
New grass stem that grows from the crown of a mature grass plant.
- Toothed
- Toothed
Jagged-edged leaf margin, usually pointy but may be rounded.
- Topdressing
- Topdressing
Method of applying a soil amendment where it is evenly distributed over an entire area.
- Topsoil
- Topsoil
Top, fertile layer of soil containing organic matter and nutrients.
- Transpiration
- Transpiration
Controlled release of water vapour through a plant�s stomata.
- Tree
- Tree
A large and tall woody plant usually having one supporting stem or trunk. Branching often begins farther up the trunk.
- Trifoliate
- Trifoliate
Leaf composed of three leaflets.
- Trunk
- Trunk
Main woody support structure of a tree.
- Tuber
- Tuber
Modified stem. It is a short, enlarged underground stem that stores nutrients.
- Twig
- Twig
Small woody projections that stem from branches.
- Umbel
- Umbel
An inflorescence (flower cluster) where many pedicels (stalks) equal in length radiate from one point on a stem.
- Undulate
- Undulate
A wavy, sinuous edge.
- Unisexual
- Unisexual
Flowers with the reproductive parts of one sex only. They are either staminate or pistillate. Also known as dioecious.
- Untoothed
- Untoothed
Smooth leaf margin without teeth. See entire.
- Variegated
- Variegated
Describes the appearance of leaves (and sometimes stems) marked with a pattern of more than one colour.
- Vascular plant
- Vascular plant
Plant that has special vascular tissues, xylem and phloem, for circulation of water, minerals and food (generated through photosynthesis) throughout the plant.
- Veins
- Veins
Line or vein-like features found throughout a leaf blade.
- Vermicomposting
- Vermicomposting
Composting with worms.
- Whorl
- Whorl
Three or more plant parts that radiate in an outward circle about the stem.
- Whorled flower
- Whorled flower
Flower arrangement where three or more flowers are at points along the stem, creating a whorled pattern.
- Whorled leaves
- Whorled leaves
Leaf arrangement where there are three or more leaves, branches or pedicels at a node. Also known as spiral leaves.
- Woods
- Woods
Area where many trees grow close together. A forested area.
- Xeriscaping
- Xeriscaping
Landscaping and gardening, which, once established, minimizes or eliminates the need for irrigation.
- Xylem
- Xylem
Tissue in a tree that carries water and nutrients up from the roots and disperses them to the branches and leaves.
- Zygomorphic
- Zygomorphic
See irregular flower.