Glossary of botanical terms

Accessory fruit: A fruit in which parts other than the ovary, such as the receptacle or hypanthium, contribute to the fleshy portion, as in strawberries or apples.

Accrescent calyx: A calyx that continues to grow and enlarge after fertilization, often enclosing or supporting the developing fruit.

Achene: A small, dry, indehiscent fruit containing a single seed that is free from the pericarp, as found in sunflowers and buttercups.

Actinomorphy: The condition of having radial symmetry, where a structure can be divided into two or more identical parts along multiple planes passing through the center.

Adventitious roots: Roots that grow from parts of the plant other than the main root system, such as stems, nodes, or leaves. They often help with support, propagation, or nutrient absorption in unusual conditions.

Aerial roots: Roots that grow above the ground, often hanging from stems or branches. They help support the plant, absorb moisture from the air, or assist in climbing.

Aggregate-accessory fruit: A fruit formed from multiple ovaries of a single flower, with additional floral parts—such as the receptacle—contributing to the fleshy portion, as in strawberries.

Aggregate fruit (or etaerio): A fruit formed from multiple ovaries of a single flower, each developing into small fruitlets clustered together, like in raspberries or strawberries.

Albuminous seed: A seed that contains a significant amount of endosperm, which serves as a food reserve for the developing embryo.

Alternate leaves: A leaf arrangement where a single leaf grows at each node, alternating sides along the stem.

Amplexicaul leaf: A leaf whose base clasps or wraps around the stem, often partially or entirely encircling it.

Androecium: The collective term for all the stamens (male reproductive organs) of a flower. It produces pollen, which contains the male gametes necessary for fertilization.

Andromonoecious plant: A plant species that bears both male flowers and bisexual flowers on the same individual.

Anisophylly: The condition in which a plant bears leaves of unequal size or shape on the same stem.

Annual plants: Plants that complete their entire life cycle—from germination to seed production—within one growing season or year, after which they die.

Anther: The part of a stamen where pollen is produced and released. It is usually located at the tip of a filament.

Antipodal cells: Three small cells located at the opposite end of the egg cell within the female gametophyte (embryo sac) of flowering plants. Their function is not fully understood, but they may support the development of the embryo sac.

Apical meristem: A region of actively dividing cells at the tip of a plant shoot or root, responsible for primary growth and formation of new organs like flowers.

Aquatic plants: Plants that grow in water or in soil that is permanently saturated with water. They have adaptations such as flexible stems, air-filled tissues, or specialized roots to survive submerged or floating conditions.

Aril: A specialized, often fleshy and colorful outgrowth from a seed that aids in attracting animals for seed dispersal.

Asexual reproduction: A type of reproduction in plants where new individuals are produced without the fusion of gametes (no seeds or spores). It often occurs through methods like runners, tubers, cuttings, or buds, resulting in offspring genetically identical to the parent.

Asymmetrical flower: A flower that cannot be divided into equal halves along any plane; it lacks any clear symmetry. This is very rare and usually found in highly specialized species.

Asymmetrical inflorescence: An inflorescence in which the flowers are unevenly distributed or arranged in a non-uniform pattern along the stem, resulting in an irregular or lopsided appearance.

Autogamy: The process of self-fertilization in plants, where pollen from a flower fertilizes ovules of the same flower.

Axil: The angle formed between the upper side of a leaf or branch and the stem from which it grows.

Axile placentation: A placentation type where ovules are attached to a central axis within a compound ovary.

Axillary inflorescence: An inflorescence that arises from the axil, the angle between a leaf and the stem.

Axillary whorl: A circular arrangement of flowers or floral parts emerging from the axil (the angle between a leaf and the stem).

Bark: The protective outer covering of the stems and trunks of woody plants. It shields the plant from physical damage, pests, and disease, and helps reduce water loss.

Basal leaf: A leaf that emerges directly from the base of a plant, typically forming a rosette near the ground; it is attached to the stem at or below the soil surface and is common in many herbaceous species.

Basal meristem: A growth region at the base of an organ, such as a leaf or root; its absence means leaf growth occurs from other regions.

Basal rosette: A circular cluster of leaves growing close to the ground from a short stem, often forming a dense, ground-level foliage base.

Basifixed anther: An anther attached to the filament at its base, allowing limited movement.

Beaked fruit: A fruit with a pointed, elongated tip resembling a bird’s beak.

Bell-shaped calyx: A calyx in which the fused sepals form a structure widening toward the apex and narrowing at the base, resembling the shape of a bell.

Berry: A type of fleshy fruit that develops from a single ovary and contains one or more seeds embedded in the fleshy pericarp.

Biennial plants: Plants that require two growing seasons to complete their life cycle, typically forming vegetative structures in the first year and flowering in the second.

Bifid stigma: A stigma that is divided into two distinct lobes or parts, which may be equal or slightly unequal in size.

Bilabiate calyx: A calyx divided into two distinct “lips,” typically with an upper and a lower part, which may aid in protecting reproductive structures and guiding pollinators.

Bilabiate corolla: A type of zygomorphic corolla in which the fused petals are arranged to form two distinct “lips“.

Bilaterally symmetrical flower (zygomorphic flower): A flower that can be divided into equal halves along only one single plane, typically showing a mirror-image shape—like in orchids or snapdragons.

Bifid stigma: A stigma that is divided into two distinct lobes or segments at the apex.

Bifoliolate leaf: A type of compound leaf that has only two leaflets attached to the petiole.

Bilobed fruit: A fruit divided into two distinct sections or lobes, often resulting from the fusion of two carpels.

Bilocular anther: An anther with two distinct chambers that contain pollen.

Bipinnate leaf: A compound leaf where the main leaf is divided into smaller leaflets arranged on secondary stems, which themselves are attached along a central main stem (rachis), giving a twice-divided, feather-like appearance.

Bitegmic ovule: An ovule with two protective layers (integuments) around the embryo sac.

Bitegmic seed: A seed that develops from an ovule with two integuments, resulting in a seed coat composed of two distinct layers: testa and tegmen.

Bisexual flower: A flower that contains both the male reproductive part (androecium) and the female reproductive part (gynoecium), enabling it to carry out reproduction on its own.

Blade: The broad, flat part of a leaf where most photosynthesis occurs. The blade’s large surface area and network of veins (nervures) allow efficient transport of water, nutrients, and food, as well as gas exchange and light absorption. It is connected to the stem by the petiole.

Bracteoles: Small bracts located on the flower stalk (pedicel), usually just below the flower itself, often helping to protect the developing flower.

Bracts: Modified or specialized leaves, often found just below a flower or inflorescence, that can protect the flowers or attract pollinators.

Bran: the outer protective layer of a cereal grain, which surrounds the seed and is rich in dietary fiber, minerals, and antioxidants.

Branch: A part of a plant that grows out from the main stem, supporting leaves, flowers, and fruits.

Bud: A small growth on a plant stem or branch that can develop into a new leaf, flower, or new shoot.

Bulb: An underground storage organ made of fleshy, layered leaves that surround a central shoot. It stores nutrients to help the plant survive dormant periods and grow again later.

Bulbil: A small vegetative bud that forms in place of a flower or within an inflorescence, capable of developing into a new plant asexually.

Bush plants: Compact plants characterized by short, woody stems with many branches, usually under one meter in height.

Calyx: The part of a flower formed by all the sepals, usually green and leaf-like, which protect the flower bud before it opens.

Cambium: A layer of lateral meristematic tissue in vascular plants responsible for secondary growth, producing new xylem (wood) inward and phloem outward. It allows stems and roots to increase in thickness.

Campanulate calyx: A calyx shaped like a bell, typically formed by fused sepals that widen outward from a narrow base.

Campanulate corolla: A bell-shaped corolla with a flaring mouth and a wider opening than the base.

Canopy: The upper layer of a plant, formed by the crowns of trees or tall shrubs. It captures sunlight for photosynthesis and provides habitat and protection for many organisms.

Capsule: A dry, usually dehiscent fruit that develops from a compound ovary and opens in various ways to release its seeds, common in many flowering plants.

Carnivorous plants: Plants that trap and digest insects or other small animals to obtain nutrients, especially in nutrient-poor soils. Examples include Venus flytrap, Nepenthes, and Sarracenia.

Carpels: The female reproductive organs of a flower, typically consisting of an ovary (which contains ovules), a style, and a stigma (which receives pollen). One or more carpels together form the gynoecium, the female part of the flower.

Caruncles: Small, fleshy outgrowths near the seed hilum that attract ants for seed dispersal.

Caryopse: Dry, one-seeded fruit where the seed coat is fused to the pericarp, forming a single, inseparable unit such as rice, maize and wheat.

Cauline leaf: A leaf that grows directly on the stem rather than at the base of the plant.

Cell: The basic unit of structure and function in all living organisms. In plants, each cell has a nucleus that contains genetic material and controls the cell’s activities.

Cell division (or mitosis): The process by which a single cell divides to produce two genetically identical daughter cells. In plants, mitosis occurs mainly in meristems and is essential for growth, tissue repair, and the formation of new organs.

Cell wall: A rigid outer layer surrounding plant cells, providing structural support and protection.

Chromosomes: Structures found inside the nucleus of a cell, made of tightly coiled genetic material. They carry the information that determines an organism’s traits and guide cell activities.

Circumscissile dehiscence: A fruit opening mechanism in which a lid-like portion detaches along a circular horizontal line, often near the top of the fruit.

Clasping flower: A flower whose base or lower parts of the petals, sepals, or bracts partially surround or tightly embrace the stem, giving the appearance of the flower “clasping” it.

Cleistogamy: A form of self-pollination in which flowers remain closed and fertilization occurs without exposure to external pollen, ensuring reproductive success under unfavorable conditions.

Climbing plants: Plants that grow upward by attaching themselves to nearby structures or plants for support. They rely on winding around or leaning on other vegetation to reach sunlight.

Chlorophyll: The green pigment found in plant cells that absorbs sunlight and drives the process of photosynthesis, allowing plants to produce energy from carbon dioxide and water.

Chlorophyll-lacking plants: Plants that do not contain chlorophyll and therefore cannot perform photosynthesis.

Collenchyma cell: A type of plant cell with unevenly thickened primary walls, providing flexible mechanical support to growing tissues while allowing elongation and expansion.

Collenchyma bundle: Cluster of collenchyma cells that gives flexible support to growing plant organs, typically found at stem corners to reinforce structure without restricting elongation.

Colpi: Longitudinal furrows or apertures on pollen grains that facilitate pollen tube emergence during fertilization.

Complete flower: A flower that has all four main parts: sepals, petals, stamens, and carpels.

Compound leaf: A leaf in which the blade is divided into multiple leaflets, each attached to a single petiole. Despite the division, all leaflets together form one single leaf.

Compound ovary: An ovary formed by the fusion of two or more carpels (the basic units of the female reproductive organ in flowers).

Conduplicate leaf: A leaf folded lengthwise along the midrib, with the two halves pressed together like a closed book.

Cone: A reproductive structure found in gymnosperms (such as pines and firs) that contains seeds. Cones can be male, producing pollen, or female, producing ovules that develop into seeds after fertilization

Conifers: A group of gymnosperm plants characterized by needle-like or scale-like leaves and seeds that develop in cones. They are mostly evergreen woody plants.

Corm: A short, vertical, swollen underground stem that serves as a storage organ in certain plants, supporting survival during adverse conditions and producing new shoots and flowers in the growing season.

Corolla: The part of a flower formed by all the petals, usually colorful and shaped to attract pollinators.

Corolla limb: The expanded, often flat or spreading upper part of the corolla, located above the tubular base and made up of the visible petals.

Corolla lip: one of the distinct segments at the opening of a bilabiate corolla, especially in zygomorphic flowers.

Corolla lobes: The separate segments or divisions of the corolla.

Corolla tube: the tubular portion of a sympetalous corolla, formed when the petals are fused together, typically at their base. It often serves to guide pollinators and protect reproductive structures.

Corona: Crown-like structure formed by the fusion or modification of petals or other floral parts, often found in flowers like daffodils (Narcissus).

Cotyledons (seed leaves): The first leaves that emerge from a germinating seed, serving as initial food storage or photosynthetic organs for the young plant.

Crassinucellate ovule: An ovule that has a thick layer of nutritive tissue (nucellus) surrounding the embryo sac.

Crenate margin: A leaf edge with rounded teeth or scalloped indentations.

Cross-pollination: The transfer of pollen from the anther of one flower to the stigma of a genetically different flower, promoting genetic diversity and variation within a plant population.

Cutting: A piece of a plant, such as a stem or leaf segment, that is cut and planted to grow a new plant genetically identical to the original.

Cylindrical calyx: A calyx shaped like a cylinder, with sepals fused or arranged to form a tube-like structure that surrounds and protects the flower before it opens.

Cymose inflorescence (determinate): An inflorescence where the main axis ends in a flower, stopping its growth, and younger flowers develop below or to the side.

Decumbent plants: Plants with stems that lie along the ground but have tips that curve upward.

Decussate leaves: A leaf arrangement in which each successive pair of leaves is positioned at right angles to the previous pair, forming a cross-like pattern along the stem.

Deeply lobed leaf: A simple leaf with prominent indentations that extend close to the midrib but do not divide the blade into separate leaflets.

Dehiscent fruit: A type of fruit that splits open at maturity to release its seeds, allowing them to disperse into the environment for germination.

Dentate margin: A leaf edge characterized by sharp, outward-pointing teeth that are roughly perpendicular to the margin, resembling the edge of a saw.

Determinate flowering pattern: A flowering pattern in which the main growing point ends with a flower, stopping further elongation of the stem or branch.

Dichasial pattern: A branching arrangement in which each axis ends in a flower or branch and produces two lateral branches, which may themselves repeat the same pattern, forming a balanced, forked structure.

Dicots: A group of flowering plants that have two cotyledons, net-like leaf veins, and flower parts usually in multiples of four or five.

Didynamous stamens: A set of four stamens where two are longer and two are shorter.

Dioecious plant: A plant in which individual plants produce either only male flowers, containing just the androecium or only female flowers, containing just the gynoecium. Male and female flowers are found on separate plants.

Diploid: Having two complete sets of chromosomes, one inherited from each parent.

Dispersal: The process by which seeds (or sometimes fruits) are spread away from the parent plant. This helps reduce competition and allows plants to colonize new areas. Dispersal can occur through wind, water, animals, or mechanical means.

Dorsifixed anther: An anther attached to the filament at its back, allowing it to pivot freely.

Drupe: A fleshy fruit with a single seed enclosed within a hard, stony endocarp, such as a peach or cherry.

Dry fruit: A type of fruit that becomes hard or papery when mature, rather than soft and juicy. It usually protects the seeds and may either split open to release them (dehiscent) or remain closed (indehiscent).

Dry seed: A type of seed that develops within a dry fruit, lacking a fleshy outer layer.

Egg cell: The female reproductive cell that carries half of the genetic material and, after fertilization by a sperm cell, gives rise to the embryo. In plants, it is located inside the ovule within the ovary of the flower.

Elaiosome: A fleshy, nutrient-rich structure attached to seeds that attracts ants, aiding in seed dispersal.

Elliptic leaf: A type of leaf that is shaped like an ellipse, being broadest at the middle and tapering gradually toward both ends.

Embryo: The young, developing plant inside a seed, formed after fertilization. It will grow into a new plant when conditions are favorable.

Embryo sac: The female gametophyte in flowering plants, located within the ovule, that contains the egg cell and other cells necessary for fertilization and early seed development. It also participates in forming the endosperm after fertilization.

Endocarp: The innermost layer of the pericarp that directly surrounds the seed, varying in texture from soft to hard (stone) depending on the fruit.

Endosperm: A tissue formed inside the seed after fertilization that provides nourishment to the developing embryo.

Endospermic seed: A seed that contains endosperm tissue, which serves as nutritive tissue for the developing embryo.

Entire margin: A leaf edge that is smooth, continuous, and unbroken.

Epipetalous stamens: Stamens that are attached to the petals rather than directly to the flower receptacle.

Epiphytes: Plants that grow on other plants for physical support but do not extract nutrients from them.

Eudicots: A large clade of flowering plants characterized by having tricolpate pollen and typically two cotyledons in the seed.

Evergreen plants: Plants that keep their leaves throughout the year instead of shedding them seasonally. This allows them to carry out photosynthesis year-round, even in winter.

Exalbuminous seed: A seed that lacks endosperm at maturity because it is fully absorbed by the developing embryo.

Exocarp: The outermost layer of the pericarp, often forming the pell or skin of the fruit.

Explosive dehiscence: A type of fruit opening mechanism where the release of seeds occurs suddenly and forcefully, often due to built-up tension in the fruit tissues.

False septa: Internal partitions in the ovary that do not correspond to the original carpel boundaries.

Female gametophyte (megagametophyte): The haploid structure within the ovule of seed plants that produces the egg cell and other supporting cells necessary for fertilization and early development. In flowering plants, it is also called the embryo sac.

Ferns: Non-flowering vascular plants that reproduce via spores instead of seeds. They have large, divided leaves called fronds and typically grow in moist, shaded environments.

Fertilization: The process in which a sperm cell from the pollen fuses with an egg cell contained within the ovule to form a zygote, which will develop into the embryo.

Fibrous root: A root system composed of numerous thin, moderately branching roots growing from the stem base, typically lacking a central dominant root. It provides efficient soil anchorage and rapid absorption of water and nutrients.

Filament: The slender stalk of a stamen that supports the anther, positioning it to effectively release pollen for pollination.

Filiform leaf: A type of leaf that is extremely narrow and thread-like, often resembling a fine filament.

Flat leaf: A type of leaf with a flattened blade, lacking folds or significant curvature, providing a broad surface for photosynthesis.

Fleshy pericarp: The soft, thickened fruit wall that develops from the ovary after fertilization and surrounds the seeds in many fruit types, especially in berries and drupes.

Fleshy fruit: A type of fruit with a soft, juicy, and edible outer layer at maturity. It develops from the ovary of a flower after fertilization and typically surrounds the seeds. Common examples include apples, peaches, tomatoes, and berries.

Floral pattern: The specific arrangement and number of floral organs—such as sepals, petals, stamens, and carpels—within a flower.

Floret: A small individual flower that is part of a larger inflorescence, such as those found in a daisy or sunflower head.

Floury perisperm: A nutritive tissue within the seed, characterized by a soft, powdery or starchy texture, that serves as a food reserve for the developing embryo.

Flower: The reproductive structure of flowering plants (angiospermae), typically composed of petals, sepals, stamens (male organs, collectively called the androecium), and carpels (female organs, collectively called the gynoecium). Flowers facilitate pollination and are the site of fertilization, leading to the formation of seeds and fruit.

Flower head (capitulum): A dense cluster of small flowers (florets) tightly packed together, often resembling a single flower.

Flowering pattern: The sequence and arrangement in which flowers bloom on a plant or inflorescence. Common types include determinate and indeterminate flowering patterns.

Flowering plants (or Angiospermae, Magnoliophytae): Plants that reproduce through flowers, which contain the male and female reproductive organs needed for fertilization. After pollination and fertilization, they produce seeds enclosed within fruits.

Flowering scape: A leafless stalk that grows from the base of a plant, often from a bulb or rhizome, and supports the flowers or inflorescence, elevating them above the leaves.

Flowering stem: The upright stalk of a plant that bears the flowers or inflorescence, rising above the leaves to facilitate pollination.

Foliage: The collective term for all the leaves of a plant. It plays a vital role in photosynthesis and contributes to the plant’s overall appearance.

Four-foliate leaf: A compound leaf divided into four distinct leaflets originating from a common point on the petiole.

Frond: The large, divided leaves of ferns and some other plants. Fronds often have a feathery appearance and are the main photosynthetic organs of these plants.

Fruit: The mature ovary of a flower, usually containing seeds. Fruits develop after fertilization and help protect the seeds and aid in their dispersal. They can be fleshy (like apples) or dry (like nuts).

Fruit locule: A cavity within a fruit’s ovary or pericarp that contains seeds; the number of locules varies by spices.

Fruit opening mechanisms: The various ways dehiscencent fruits release their seeds at maturity.

Fruit spreading: The process by which fruits (and their seeds) are dispersed away from the parent plant, often through wind, water, animals, or mechanical means.

Fruiting: The stage in a plant’s life cycle during which it produces and matures fruits, enabling the dispersal of seeds for reproduction.

Fruitlet: A small individual fruit that is part of an aggregate or a multiple fruit.

Funiculus: The stalk that attaches the seed to the ovary wall or fruit, providing nutrients during seed development.

Funnel-shaped corolla: A corolla that gradually widens from a narrow base to a broad, open top, like a funnel.

Gamete: The reproductive cell that carries half of the genetic material of an organism. In plants, the male form is the sperm cell found in pollen, and the female form is the egg cell located within the ovule.

Gametophyte: The gametophyte is the haploid stage in the plant life cycle that produces gametes (sperm and egg cells). In seed plants, the male gametophyte is found inside pollen grains, while the female gametophyte develops within the ovule. It is responsible for sexual reproduction by generating the reproductive cells needed for fertilization.

Gamosepalous calyx: A type of calyx in which the sepals are fused together, at least at their base, forming a single, often tubular, bell-shaped, or cup-like structure, instead of remaining as distinct, separate units.

Gamopetalous corolla: A corolla in which the petals are fused together, at least at the base, forming a tubular or bell-shaped structure.

Gas exchange: The process by which gases such as oxygen and carbon dioxide are exchanged between a plant and the environment, mainly through small openings called stomata in the leaves. This exchange is essential for photosynthesis.

Genetic material: The substance inside the nucleus of a cell, made up of chromosomes, that carries the information needed to guide the cell’s functions and development.

Geophilous shoot: A shoot that grows directly into the soil, helping to stabilize the plant and support woody plants where the primary stem lacks sufficient mechanical strength.

Geoxylic structure: Specialized woody plant formation in which the bulk of the stem and branching system is concentrated underground, often as a response to fire, grazing, or drought, allowing regeneration through subterranean buds.

Germ: The embryo of a cereal caryopsis, from which a new plant can develop during germination. It is the living part of the seed and contains concentrated nutrients such as oils, proteins, vitamins, and minerals, making it the most valuable fraction of the grain.

Germination: The process by which a seed develops into a new plant, beginning with the seed absorbing water and ending with the emergence of the seedling.

Gland: A small secretory structure, often composed of specialized cells, that produces substances and may appear on leaves, stems, or flowers.

Glandular trichomes: Specialized plant hairs containing glands that can secrete substances like oils or resins, often involved in defense or attraction.

Globose fruit: A fruit that is spherical or nearly spherical in form.

Green pigment: Substance like chlorophyll that gives plants their green color and plays a key role in photosynthesis by capturing light energy.

Grooved leaf: A leaf whose blade shows one or more longitudinal indentations or channels, often aiding in water drainage or structural support.

Gynobasic style: A type of style that arises from the base of the ovary, often appearing to emerge from between the lobes of the ovary itself.

Gynoecium: The collective term for all the carpels (female reproductive organs) of a flower. It includes the ovary, style, and stigma, and is responsible for producing ovules and receiving pollen during fertilization.

Gynophore: A stalk-like structure that elevates the gynoecium above the base of the flower, providing physical separation from other floral parts and sometimes aiding in pollination.

Gymnosperms: They are a group of seed plants whose seeds are not enclosed within a fruit. Instead, their seeds develop on the surface of scales or leaves, often arranged in cone.

Hairy seed: A seed covered with trichomes or hair-like outgrowths of the seed coat, which may aid in dispersal by wind, water, or attachment to animals. In some species, these hairs also provide a degree of protection or help retain moisture.

Haploid: Having a single set of chromosomes. In plants, haploid cells or structures, such as gametes and gametophytes, contain half the genetic material and are involved in sexual reproduction.

Hard (or stone) endocarp: The tough, rigid innermost layer of the pericarp that encloses and protects the seed, commonly found in drupes like peaches and cherries.

Herbaceous plants (herbs): Plants with soft, non-woody stems that usually die back to the ground at the end of the growing season.

Hermaphroditic flower: A flower that contains both male (stamens) and female (carpels) reproductive organs, allowing it to potentially self-pollinate or cross-pollinate with other flowers.

Hexacolpate pollen: Pollen grains with six furrows or pores (colpi).

Hilum: The scar on a seed marking the point where it was attached to the ovary via the funiculus.

Horny endosperm: A hard and tough type of endosperm with thickened cell walls, providing structural support to the seed.

Hypanthium: A cup/tube-shaped floral structure formed by the fusion of the bases of the sepals, petals, and stamens, often surrounding or supporting the ovary.

Hypocotyl: The stem-like part of a seedling located below the cotyledons and above the root, which helps push the seedling above the soil during germination.

Hyperphyll: the apical portion of a cotyledon or leaf, often responsible for photosynthesis and other metabolic functions, in contrast to the basal hypophyll which may provide structural support or storage.

Hypophyll: the basal portion of a cotyledon or leaf, often dominant in monocotyledons, providing structural support and sometimes storage functions, in contrast to the distal hyperphyll.

Imparipinnate leaf: A type of compound leaf in which an odd number of leaflets is arranged in pairs along a central rachis, ending with a single terminal leaflet at the tip.

Incomplete flower: A flower that lacks one or more of the four main floral parts: sepals, petals, stamens, or carpels.

Indehiscent fruit: A type of fruit that does not open at maturity; the seeds remain enclosed until the fruit decays or is eaten, aiding seed dispersal.

Indeterminate flowering pattern: A flowering pattern where the main growing point continues to produce new flowers without stopping stem or branch elongation.

Inferior ovary: An ovary positioned below the attachment of the other floral parts (such as petals, sepals, and stamens), so that these structures appear to arise above it.

Inflorescence: A cluster of flowers arranged along a plant’s stem, which can consist of a single main branch or a network of branches. It is classified based on how the flowers are positioned on the main axis (peduncle) and by the flowering pattern.

Infructescence: A cluster of fruits that develops from an inflorescence, remaining attached to the same stem or branch.

Integument: The protective layer of cells that surrounds the ovule and later forms the seed coat.

Internode: The segment of a plant stem between two nodes. It determines the spacing of leaves and branches along the stem and can vary in length depending on the plant species and growth conditions.

Introrse anther: An anther that opens inward, toward the center of the flower.

Irregular dehiscence: A fruit opening mechanism without a consistent structural pattern, where the fruit splits in an unpredictable or uneven way.

Lanceolate leaf: A leaf that is longer than wide, tapering to a point, with the widest part below the middle.

Leaf: A flattened, typically green plant organ attached to the stem, responsible for photosynthesis, gas exchange, and transpiration. Leaves usually consist of a blade (the broad, flat part) and a petiole (the stalk that connects the blade to the stem).

Leaf sheath: The basal part of a leaf that wraps around the stem or bulb, providing support and protection for the growing shoot or flower.

Leaflet: A smaller, individual segment that is part of a compound leaf. It resembles a simple leaf but is only one part of the whole leaf.

Leathery fruit: A type of fruit with a tough, somewhat flexible pericarp that is resistant to splitting but not lignified.

Legume (pod): A dry fruit that splits along two seams.

Lever-like anther: An anther that functions mechanically like a lever, moving when triggered by a visiting pollinator to deposit pollen on specific parts of the pollinator’s body, enhancing pollen transfer efficiency.

Lianas: Long, woody climbing plants that use other trees or structures for support as they grow upward toward the sunlight. They are common in tropical forests.

Linear leaf: A type of leaf that is long and narrow with nearly parallel margins, maintaining a consistent width along its length.

Lip: A specialized petal, often enlarged or uniquely shaped, forming part of the corolla in certain flowers, usually adapted to attract pollinators or facilitate pollination.

Lobe: A rounded or projecting part of a plant organ, such as a leaf, petal, or fruit, often separated by indentations or sinuses.

Lobed leaf: A leaf with large, rounded or pointed projections (lobes) that are not completely separated from the main blade.

Lobed margin: A leaf edge that has large, rounded or pointed projections (lobes).

Longitudinal dehiscence: The process by which anthers open lengthwise along their sides to release pollen.

Loculicidal dehiscence: A type of fruit opening in which each chamber splits longitudinally to release seeds.

Male gametophyte: The haploid structure in seed plants that produces the sperm cells needed for fertilization. In both gymnosperms and flowering plants (angiospermae), it develops inside the pollen grain and is responsible for delivering the sperm cells to the ovule.

Maternal integument: The outer tissue layer of the ovule, derived from the parent plant, which develops into the seed coat after fertilization.

Meiosis: A type of cell division in which a diploid cell undergoes two successive divisions to produce haploid cells, reducing the chromosome number by half. It is essential for sexual reproduction and genetic variation.

Meristem: A region in a plant where cells actively divide and remain unspecialized. It is responsible for growth and the formation of new organs like leaves, roots, and flowers. A meristem is found at the tip of roots and shoots, and in certain internal tissues.

Mesocarp: The middle layer of the pericarp, typically the fleshy or pulpy part of the fruit between the exocarp and endocarp.

Microspore: A haploid spore produced by meiosis, which develops into a male gametophyte (pollen grain) in seed plants.

Microsporogenesis: The process in which microspore mother cells undergo meiosis to produce haploid microspores, which then develop into pollen grains. It can occur in two forms: successive, where cell walls form after each meiotic division, or simultaneous, where walls appear only after both divisions are complete.

Midrib (costa): The central, main vein running down the middle of a leaf blade, providing structural support and transporting nutrients and water.

Monocolpate pollen: Pollen grains that have a single elongated furrow or aperture (called a colpus) through which the pollen tube can emerge during germination.

Monocots: A group of flowering plants characterized by having a single cotyledon, parallel leaf veins, and flower parts typically in multiples of three.

Monoecious plant: A plant that produces separate male and female flowers on the same individual. Male flowers contain only the androecium, while female flowers contain only the gynoecium.

Mosses: Small, non-vascular plants that typically grow in dense green clumps or mats in moist environments. They do not have true roots, stems, or leaves, and they reproduce via spores rather than seeds.

Mucilaginous fruit surface: A fruit surface that produces or contains a sticky, gelatinous substance, often aiding in water absorption or dispersal.

Multiple-accessory fruit: A fruit formed from an entire inflorescence, where both the ovaries of many flowers and additional floral parts (like the receptacle or bracts) contribute to the fleshy structure, as in pineapple.

Multiple fruit: A fruit formed from the ovaries of multiple flowers that fuse together into a single mass, such as a pineapple or fig.

Nectar: A sugary liquid secreted by flowers to attract pollinators such as bees, butterflies, and birds. It serves as a food reward and aids in pollination.

Nectar disk: A specific type of nectary, often disc-shaped, located near the ovary base that secretes nectar to attract pollinators.

Nectary: A gland in a flower (or sometimes on other plant parts) that produces nectar to attract pollinators.

Needle-like leaves: Thin, long, and pointed leaves typical of many coniferous plants. Their shape helps reduce water loss and withstand cold or dry conditions.

Nitrogen fixation: The process by which certain organisms convert atmospheric nitrogen (N₂) into forms that plants can absorb and use, such as ammonia. In plants, this often occurs through symbiosis with bacteria living in root nodules.

Node: The part of a plant stem where leaves, branches, or buds are attached. It is a key growth point and often plays a role in the development of new shoots or roots.

Nodule: A specialized swelling or growth, often found on the roots of certain plants like legumes, that houses nitrogen-fixing bacteria (rhizobia) which convert atmospheric nitrogen into a form usable by the plant.

Non-flowering plants: Plants that do not produce flowers but reproduce using seeds or spores. They include groups like ferns and mosses (which reproduce via spores), and gymnosperms (which produce seeds but no flowers).

Non-vascular plants: Plants that lack vascular tissues (xylem and phloem) for transporting water, nutrients, and food. Because of this, they are usually small and grow close to the ground in moist environments.

Nucellus: The central tissue of the ovule that encloses and nourishes the developing embryo sac.

Nucleus: The control center of the cell. It contains the genetic material and directs the cell’s growth, division, and activities.

Nutlet: A small, hard, one-seeded fruit that usually results from the splitting of a larger fruit into multiple segments.

Nutrient storage: The reserve of food within a seed that nourishes the embryo during germination and early growth. In flowering plants, this stored nutrient is called the endosperm.

Oblong leaf: A type of leaf that is longer than it is wide, with parallel or slightly curved sides and rounded ends.

Obovoid fruit : A fruit shaped like an egg, but with the broader end toward the apex.

Odd-pinnate leaf: A compound leaf with an odd number of leaflets arranged along a central axis, terminating in a single terminal leaflet.

Offset: A small secondary bulb or shoot that develops from the base of a parent plant, allowing asexual reproduction and the formation of new, genetically identical plants.

Oil gland: Specialized plant structure that synthesizes and stores volatile oils, responsible for distinctive aromas and fragrances.

One-seeded fruit: A fruit that contains only a single seed enclosed within its pericarp.

Opposite leaves: A leaf arrangement where pairs of leaves grow at the same level, directly across from each other on the stem.

Orbicular leaf: A leaf with a blade that is nearly circular in outline, with length and width approximately equal.

Orobranchin: A chemical compound present in some parasitic plants responsible for their brown coloration when dried.

Ovary: The part of a flower that contains one or more ovules. After fertilization, the ovary develops into a fruit, protecting the seeds inside. It is a component of the female reproductive organ of the flower, called the gynoecium.

Ovary wall: The outer layer of the ovary that develops into the pericarp after fertilization.

Ovate leaf: A leaf shaped like an egg, broader at the base.

Ovoid fruit: A fruit shaped like an egg, with one end broader than the other, typically three-dimensional and symmetrical along its long axis.

Ovule: It is a small structure inside the ovary of a flower where the female gametophye (megametophyte) develops. After fertilization by pollen, the ovule matures into a seed.

Palmate venation pattern: A venation pattern where several main veins spread out from a single point at the base of the leaf, resembling the fingers of a hand.

Palmately compound leaf: A type of compound leaf where multiple leaflets spread out from a single point at the end of the petiole, resembling the fingers of a hand.

Paniculate inflorescence: An inflorescence in which the main axis bears lateral branches that themselves may be further branched, with flowers typically borne on the ultimate branches. It allows a large number of flowers to be displayed efficiently.

Pappus: A modified calyx that aids in seed dispersal, especially by wind, commonly found in the Asteraceae family.

Parallel venation pattern: a type of leaf venation pattern in which the veins run mostly parallel along the length of the leaf, typical of most monocotyledons.

Parasitic plants: Plants that obtain some or all of their nutrients from another living plant (host), often causing harm to the host.

Pedicel: The small stalk that supports a single flower in a cluster or inflorescence.

Pedicellate flower: A flower that is borne on a pedicel, a small stalk that connects the flower to the main stem or inflorescence axis.

Peduncle: The main stalk or stem that supports an inflorescence or a single flower. It connects the flowers to the rest of the plant.

Peel (or skin): The outer protective layer of a fruit, often corresponding to the exocarp, which can be either edible or inedible depending on the species.

Pendulous spike: A type of inflorescence in which flowers are arranged along a central stem (spike) that hangs or droops downward due to its weight or growth pattern.

Pentamerous flower: A flower with floral organs arranged in five parts per whorl, commonly referring to perianth parts.

Perennial plants: Plants that live for more than two years, often producing flowers and seeds multiple times throughout their lifespan. They survive adverse seasons by means of underground structures like roots, bulbs, or rhizomes.

Perianth: The outer part of a flower, formed by the calyx (made up of sepals) and the corolla (made up of petals), which protects the reproductive organs and can attract pollinators.

Pericarp: The part of a fruit formed from the ovary wall after fertilization, typically divided into three layers: exocarp, mesocarp, and endocarp.

Perigone: The outer floral envelope of a flower, consisting of tepals when the calyx and corolla are not clearly differentiated. It often serves to attract pollinators visually or olfactorily and may provide a landing platform for insects.

Persistent calyx: A calyx that remains attached to the plant after the flower has withered.

Petals: The colorful parts of a flower that surround the reproductive organs. Petals collectively form the corolla, which along with the sepals (forming the calyx) makes up the perianth. The corolla often attracts pollinators with its bright colors and scent.

Petiolated leaf: A leaf that is attached to the stem by a petiole.

Petiole: The stalk that connects a leaf blade to the plant stem, supporting the leaf and allowing transport of water, nutrients, and sugars.

Petiolule: The small stalk that attaches a leaflet to the main axis (rachis) of a compound leaf.

Phloem: A type of vascular tissue in plants responsible for transporting sugars and other organic nutrients produced during photosynthesis from the leaves to other parts of the plant for growth, storage, or energy use.

Photosynthesis: A process by which green plants use sunlight, carbon dioxide, and water to produce glucose (a type of sugar) and oxygen. It takes place mainly in the leaves and provides energy for the plant’s growth.

Phyllody: A condition in which floral organs, such as petals or stamens, transform into leaf-like structures

Phyllotaxis (or leaf arrangement): The arrangement of leaves on a stem or branch. It influences how efficiently a plant captures sunlight.

Phytomelanin: A dense, black, carbon-rich pigment deposited in the seed coat. It forms a hard, crust-like outer layer that protects the seed from mechanical damage, desiccation, and sometimes predation.

Pinnate venation pattern: A leaf venation type in which a single main vein runs along the center of the leaf, giving rise to smaller lateral veins arranged like the vanes of a feather.

Pinnately compound leaf: A compound leaf in which leaflets are arranged in pairs along both sides of a central rachis, resembling the structure of a feather.

Pinnatifid leaves: Compound or deeply lobed leaves with segments arranged along both sides of a central vein.

Pinnatisect leaf: A type of leaf in which the blade is divided deeply into lobes or segments that extend almost to the central vein, giving a feather-like appearance, while remaining a single continuous structure.

Pinnule: The smallest individual leaflet found on a twice or more finely divided compound leaf.

Pistil: The individual female reproductive unit of a flower, composed of one or more fused carpels; distinct from the gynoecium, which refers to the collective set of all pistils or carpels in a flower.

Placenta: The tissue within the ovary to which ovules are attached, providing them with nutrients during development.

Placentation: The arrangement and attachment of ovules within the ovary, including the structure and position of the placenta where the ovules are borne.

Polar nuclei: Two haploid nuclei located in the center of the embryo sac of flowering plants. They fuse with a sperm cell during fertilization to form the triploid endosperm, which nourishes the developing embryo.

Pollen: The fine powder produced by the male part of a flower (anther), containing the male gametes, necessary for fertilization of the ovules.

Pollen tube: The structure that forms after a pollen grain lands on the stigma, allowing sperm cells to travel from the pollen to the ovule. It grows through the style and delivers the sperm cells to the egg cell for fertilization.

Pollen sac (theca): A chamber within the anther of a flower where pollen grains are produced and stored before being released.

Pollination: The process by which pollen is transferred from the male part of a flower (anther) to the female part (stigma), enabling fertilization and the production of seeds.

Pollinator: An organism, such as a bee, butterfly, bird, or bat, that transfers pollen from the male parts (anthers) of a flower to the female parts (stigma) of the same flower or of another flower of the same species, enabling fertilization and reproduction.

Pseudanthia: A type of inflorescence that looks like a single flower but is actually composed of multiple small flowers called florets clustered closely together.

Pseudonectary: A structure on a flower that mimics a nectar gland to attract pollinators, but does not produce actual nectar.

Pubescence: The presence of soft, short hairs (trichomes) covering the surface of a plant organ, such as leaves or stems, which can serve protective or adaptive functions.

Racemose inflorescence (indeterminate): An inflorescence where the main axis continues to grow and produce flowers, with older flowers at the base.

Rachis: The central axis of a compound leaf to which the leaflets are attached. It is an extension of the petiole.

Radially symmetrical flower (actinomorphic flower): A flower that can be divided into equal halves along multiple planes passing through its center, like a daisy or lily.

Receptacle: The part of a flower’s stalk where calyx, corolla, androecium, and gynoecium are attached.

Raphe: A ridge or seam on a seed formed by the fusion of the funiculus to the seed coat.

Reniform leaf: A leaf shaped like a kidney, broader than long, with a notch at the base.

Reproductive organs: The parts of a flower involved in sexual reproduction. These include the stamens (male organs, forming the androecium), which produce pollen that contains the male gametes (sperm cells) and the carpels (female organs, forming the gynoecium), which produce ovules that contain the female gametes (egg cells).

Resupination: A developmental twisting of the flower or floral parts, often resulting in the flower being upside down.

Reticulated venation: A venation pattern where veins form a network resembling a net across the leaf blade.

Rhizomes: Horizontal underground stems that grow beneath the soil surface. They store nutrients and can produce new shoots and roots, helping the plant spread and survive adverse conditions.

Root: A plant organ typically found underground, responsible for anchoring the plant in the soil and absorbing water and nutrients essential for growth. Roots also store food and can engage in symbiotic relationships with soil microorganisms.

Root nodule: A small swelling on the roots of certain plants that houses nitrogen-fixing bacteria.

Rosette: An arrangement of leaves, scales, or other plant structures radiating from a short stem at ground level or at the tip of a stem, forming a circular cluster.

Rotate corolla: A corolla with a short tube and a flat, circular limb that spreads widely like a wheel.

Ruminated endosperm: An endosperm with a mottled or irregularly patterned surface caused by infoldings of the seed coat into the tissue.

Runner: A horizontal stem that grows along the soil surface and produces new plants at its nodes. It allows a plant to spread and reproduce asexually.

Sap: The fluid that circulates within a plant, containing water, minerals, and organic nutrients, which transports essential substances to support growth, metabolism, and storage.

Sarcotesta: A fleshy, often brightly colored outer layer of the seed coat that aids in seed dispersal by attracting animals.

Scale: A small, thin, and often flat structure found on plants, such as on buds, stems, or cones, that can protect delicate tissues or help reduce water loss.

Scape: A leafless stem that arises directly from the ground or a basal rosette, supporting the inflorescence or a single flower.

Scale-like leaves: Small, thin, and overlapping leaves that resemble tiny scales, commonly found on some conifer plants. They help reduce water loss and protect the plant.

Schizocarp: A dry fruit that splits at maturity into multiple separate segments, each containing a seed, as in celery.

Scutellum: A specialized, shield-shaped cotyledon found in the seeds of caryopses, functioning in nutrient absorption during germination.

Secondary growth: The process in vascular plants by which stems and roots increase in thickness through the activity of the cambium.

Seed: The mature fertilized ovule of a plant, containing the embryo and nutrient storage all enclosed within a protective seed coat. Seeds are capable of developing into a new plant under suitable conditions.

Seed coat: The protective outer layer of a seed. It surrounds the embryo and nutrient storage, shielding them from physical damage, dehydration, and pathogens.

Seed plants: Seed plants are a group of plants that reproduce through seeds, which contain the embryo and nutrient storage for its development. This group includes gymnosperms (like conifers) and flowering plants (angiospermae). Seed plants have specialized structures for reproduction, such as pollen and ovules.

Seed wings: Thin, flat extensions of the seed coat that help seeds disperse by wind.

Seedling: A young plant that develops from a germinated seed and begins to grow roots, stems, and leaves.

Sepals: The green, leaf-like parts of a flower that typically form the outermost whorl. Sepals collectively make up the calyx, which protects the developing flower bud before it opens. Together with the petals (which form the corolla), sepals make up the perianth.

Septa: Internal walls or partitions within a fruit or ovary that divide it into separate chambers.

Septicidal dehiscence:A fruit opening mechanism that occurs along the septa, splitting the fruit into its original carpels.

Serrated magrin: Leaf margins that have tooth-like projections pointing toward the leaf apex, resembling a saw blade.

Sessile flower: A flower that is attached directly to the stem or branch without a stalk (pedicel).

Sessile gland: A glandular structure lacking a stalk, directly attached to the surface of an organ (such as a leaf, stem, or petal), often involved in secretion of substances.

Sessile leaf: A leaf that attaches directly to the stem without a petiole.

Sexual reproduction: A process in which male and female gametes combine through fertilization to create a new plant with genetic material from both parents. In plants, the male gametes are sperm cells contained in pollen, and the female gametes are egg cells contained in ovules.

Sheath: A protective, often tubular structure that surrounds the base of a leaf or stem. It helps support the leaf and sometimes protects young shoots.

Shell: A hard, protective outer covering found in some seeds, nuts, or fruits. It helps protect the contents from physical damage, dehydration, and predators.

Shoot: A young stem or branch of a plant, including new leaves and buds, that grows from the main stem or root.

Shrubs: Woody plants with multiple stems that are shorter than trees. They typically grow close to the ground and have a dense, bushy appearance.

Silique: A dry, elongated fruit that splits open along two seams, typical of plants in the Brassicaceae

Simple-accessory fruit: A fruit developed from a single ovary , where tissues other than the ovary, such as the floral receptacle, form part of the edible flesh, as in apples.

Simple fruit: A fruit that develops from a single ovary of one flower, such as a cherry or a tomato.

Simple leaf: A leaf with a single, undivided blade connected to the stem by a petiole. It is not divided into smaller leaflets.

Simple stigma: A stigma that is undivided, consisting of a single lobe or receptive surface.

Simultaneous microsporogenesis: A type of microsporogenesis in which the cell walls form only after both meiotic divisions are complete, producing four separate haploid microspores at once.

Soft and fleshy endosperm: A moist, nutrient-rich tissue inside some seeds that provides food for the developing embryo.

Soft endocarp: A fleshy or tender innermost layer of the pericarp that surrounds the seed, allowing easier access compared to hard or stony endocarps.

Sperm cell: The male reproductive cell that carries half of the genetic material and is responsible for fertilizing the egg cell. In plants, it is produced within the pollen and reaches the egg through the pollen tube.

Spathe bract: A specialized leaf-like structure that surrounds or subtends an inflorescence, often fused and sometimes forming a protective sheath.

Spike: An unbranched inflorescence where sessile flowers (without stalks) are attached directly along a central stem.

Spine: A sharp, pointed structure that develops from a modified leaf or part of a leaf. It serves mainly as protection against herbivores and reduces water loss in some plants like cacti.

Spiny leaf: A leaf modified to bear sharp, rigid projections (spines) along its margin, surface, or tip, primarily functioning as a defense against herbivores and sometimes reducing water loss.

Spiral phyllotaxy: A type of leaf arrangement where leaves are arranged in a helical pattern around the stem.

Spore: A tiny reproductive cell produced by certain plants that can develop into a new individual without fertilization. In plants like mosses and ferns, spores are used instead of seeds to reproduce and disperse.

Stalk: A general term for the stem or stem-like part that supports a leaf, flower, or fruit. It connects these structures to the main plant body.

Stamens: The male reproductive organs of a flower, consisting of a filament topped by an anther where pollen is produced. All the stamens together form the androecium, which is one of the main reproductive structures of the flower.

Staminode: A sterile stamen—that is, a stamen that does not produce pollen. They serve roles in attracting pollinators, protecting fertile organs, or mechanically aiding pollination.

Starch: A carbohydrate composed of glucose units, serving as the primary energy storage molecule in plants.

Starchy endosperm: The tissue inside seeds that stores starch, providing energy for the developing embryo during germination.

Stem: A main structural plant organ that supports leaves, flowers, and fruits, and acts as a conduit for transporting water, nutrients, and sugars between roots and aerial parts. Stems contain vascular tissues—xylem for water transport and phloem for nutrient transport—and can also store food and produce new growth through buds.

Stigma: The part of the carpel of a flower that receives pollen during pollination. It is often sticky or feathery to help capture pollen grains.

Stipel: A small, leaf-like appendage found at the base of a leaflet in some compound leaves. It is similar in function and form to a stipule but occurs on individual leaflets rather than the whole leaf.

Stipule: Small leaf-like or scale-like appendages found at the base the petiole in some plants. They can protect young leaves or have other functions depending on the species.

Stomata: Small pores mostly found on the underside of leaves that allow gases like oxygen, carbon dioxide, and water vapor to pass in and out of the plant. They play a key role in gas exchange and transpiration.

Stone: The hard, woody part of the fruit’s endocarp that surrounds and protects the seed, commonly found in drupes (stone fruits).

Strap-like leaf: A type of leaf that is long, flat, and narrow, resembling a strap in shape.

Style: The stalk-like part of the carpel that connects the stigma to the ovary. It allows pollen tubes to grow down to reach the ovule for fertilization.

Successive microsporogenesis: A type of microsporogenesis in which cell walls form after each meiotic division, resulting in four separate haploid microspores.

Succulent geophyte: A plant that survives unfavorable seasons through underground storage organs such as bulbs, corms, or tubers, while producing fleshy, water-storing leaves or stems during active growth periods.

Succulent plants: Plants that have thick, fleshy tissues adapted to store water. They are commonly found in arid environments and include species like aloe, agave, and many cacti.

Suffrutescent chamaephyte: A perennial plant form characterized by a partly woody base and herbaceous upper shoots, with renewal buds located close to the ground surface (usually within 25 cm), allowing survival under adverse conditions such as grazing or frost.

Suffruticose plants: Plants with a partially woody base and herbaceous upper stems, often surviving unfavorable seasons through their woody base.

Superior ovary: An ovary positioned above the point of attachment of other floral parts (sepals, petals, stamens), meaning the ovary is free and sits above the receptacle.

Symbiotic relationships: A close and long-term interaction between two different organisms that benefits at least one of them. In plants, this often involves relationships with fungi or bacteria that help with nutrient uptake.

Sympetalous corolla: A corolla in which the petals are fused together, at least at the base, forming a tubular, bell-shaped, or funnel-shaped structure.

Syncarpous ovary: An ovary in which carpels are completely united into a single pistil.

Synergid cells: Two specialized cells located next to the egg cell within the female gametophyte (embryo sac) of flowering plants. They help guide the pollen tube toward the egg cell and assist in the fertilization process.

Tegmen: The inner layer of the seed coat, usually thinner and more delicate than the outer layer (testa). It derives from the inner integument of the ovule.

Tendril: A slender, coiling structure that some climbing plants develop to grasp and anchor onto nearby supports, helping the plant grow upward.

Tenuinucellate ovule: An ovule in which the nucellus is reduced to a few cell layers, placing the embryo sac close to the surface.

Tepals: Floral parts that are not clearly differentiated into petals and sepals, typically found in flowers where all outer segments look similar, such as in lilies or tulips.

Terminal inflorescence: An inflorescence that forms at the tip of a stem or branch.

Ternate leaf: Compound leaf divided into three leaflets arising from a single point.

Testa: The outer layer of the seed coat, derived from the outer integument, often serving as the main protective covering of the seed.

Tetrachene: A type of dry fruit that splits into four one-seeded segments (nutlets) at maturity.

Tetracyclic flower: A flower composed of four distinct whorls—typically calyx, corolla, androecium, and gynoecium—arranged concentrically around the receptacle.

Tetramerous flower: A flower with floral organs arranged in four whorls, typically calyx, corolla, androecium, and gynoecium.

Tetrasporangiate anther: An anther that contains four pollen sacs, typically arranged in two pairs, where pollen develops and matures.

Thick root: A root that becomes enlarged due to the accumulation of storage tissues, often serving as a reservoir of nutrients and water. It may develop from a primary root or from adventitious roots, and is common in plants adapted to survive unfavorable conditions.

Thyrsoid inflorescence: A type of compound inflorescence in which the main axis grows indeterminately while the lateral branches are determinate, producing a mixed structure that is typically pyramidal or elongated.

Toothed margin: A leaf edge with small, sharp or saw-like projections.

Transpiration: The process by which water vapor is lost from a plant, mainly through small openings called stomata in the leaves. Transpiration helps regulate temperature and enables the movement of water and nutrients from roots to leaves.

Trees: Large, woody plants with a single main stem called a trunk, supporting branches and leaves. They can live for many years and play important roles in ecosystems by providing oxygen, habitat, and resources.

Triangular fruit: A fruit with a roughly three-sided shape, which can be angular or slightly rounded at the edges.

Trichome (hair): A small hair-like projection on a plant surface, often involved in protection, secretion, or reducing water loss.

Tricolpate pollen: Pollen grains with three furrows or pores (colpi), a defining feature present in all eudicots.

Trifoliate leaf: A compound leaf composed of three distinct leaflets emerging from a single petiole, commonly found in many plant species.

Trigonous fruit : A fruit with three distinct angles or sides, often giving a triangular cross-section.

Triploid: Having three complete sets of chromosomes (3n) instead of the usual two. In plants, this condition often arises in the endosperm after fertilization and can influence seed development and viability.

Trunk: The main woody stem typical of trees and other woody plants. It supports the branches and leaves and contains vascular tissues (xylem and phloem) that transport water, nutrients, and sugars between the roots and the canopy.

Tuber: A thickened, underground part of a stem that stores nutrients. It helps the plant survive dormant seasons and can produce new shoots. Unlike roots, tubers have buds or “eyes” from which new plants can grow.

Tuberous roots: Swollen roots that store nutrients, similar in appearance to tubers but structurally different. Unlike tubers (which are modified stems), tuberous roots are true roots and do not have buds or “eyes.” They help the plant survive unfavorable seasons and regrow.

Tubular calyx: A calyx in which the sepals are fused into a tube-like structure, elongated and cylindrical.

Tubular corolla: A corolla shaped like a long, narrow cylinder, with little distinction between tube and limb.

Umbel: A type of inflorescence where all flower stalks (pedicels) emerge from the same point, like the ribs of an umbrella.

Unitegmic seed: A seed that develops from an ovule with a single integument, resulting in a seed coat with only one layer.

Unisexual flower: A flower that has either the androecium (male reproductive part) or the gynoecium (female reproductive part), but not both.

Unitegmic ovule: An ovule with only one protective layer (integument) around the embryo sac.

Unspecialized cell: A cell that has not yet developed a specific structure or function. In plants, these cells are found in meristems and can divide to form all other types of plant cells.

Urceolate corolla: A bell-shaped corolla that is swollen in the middle and constricted at the opening, resembling a small urn or pitcher.

Valve: A flap or segment of the anther that opens to release pollen in some species.

Vascular plants: Plants that have vasular tissues (xylem and phloem) for transporting water, minerals, and nutrients throughout the plant. This system allows them to grow larger and live in a variety of environments. Examples include gymnosperms, ferns, and flowering plants.

Vascular tissue: A group of specialized parts inside the stem, made up of xylem and phloem, that transport water, minerals, and nutrients throughout the plant. It also helps support the plant’s structure.

Veins (nervatures): The vascular structures within a leaf that form a network of tubes transporting water, nutrients, and sugars. They provide support and help distribute resources throughout the leaf.

Venation pattern: The arrangement of veins in a leaf. It determines how nutrients and water are transported and provides structural support to the leaf blade.

Verticillaster: An inflorescence formed by pairs of flowers positioned opposite each other at a node, creating the appearance of a circular arrangement around the stem.

Vessel: A tube-like cell found in the xylem of most flowering plants, responsible for efficiently transporting water and minerals from the roots to the leaves.

Vines: Plants with long, flexible stems that climb or trail on other plants or structures for support. They can be woody or herbaceous.

Wavy margin: A leaf edge that undulates gently without clear teeth or lobes.

Whorl: The circular arrangement of flower parts (calyx, corolla, androecium, and gynoecium) that is attached at the same level around the stem or receptacle.

Whorled leaves: Leaves that grow in a circular pattern around a single point or node on the stem, with three or more leaves radiating from the same level.

Woody fruit: A type of fruit with a hard, lignified pericarp that typically remains closed at maturity.

Woody plants: Plants that produce hard, lignified stems and branches that persist year after year. This group includes trees, shrubs, and some vines.

Xylem: A type of vascular tissue in plants responsible for transporting water and dissolved minerals from the roots to the rest of the plant. It also provides structural support.

Zygomorphy: The quality or condition of having bilateral symmetry, where an organism or structure can be divided into two mirror-image halves along only one plane.

Zygote: The cell formed when a male gamete, contained in pollen, fertilizes a female gamete, contained in ovules. The zygote will develop into an embryo and eventually grow into a new plant.