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Student Botanical Dictionary  

Acute: Terminating in a sharp point with more or less straight sides.

Acuminate: Gradually tapering to a sharp point and forming concave sides along the tip. [HJ]

Adventitious root: Root arising from part of plant other than root; usually produced laterally on aerial stems.

Aerial roots: Roots that grow above ground and are not covered by soil or water. [GT]

Algae (singular Alga): A simple and primitive group of photosynthetic organisms formerly placed in the Plant Kingdom but now put in Kingdom Protista. Many are single-celled, but others are multicullular, including algae known as seaweeds.

Alluvial: Soil composed of sand, clay or silt which has been dispersed by water.

Alternate: Leaves arranged singly along a twig or a shoot, and not in whorls or opposite pairs.

Angiosperms: The flowering plants. Plants that produce flowers in which the egg cells (ovules) are covered by a tissue called the ovary. The ovules develop into seeds and the ovary into a covering called the fruit.

Annual: A plant that emerges from seeds and goes through its entire life cycle in just one growing season.

Anther: the pollen-producing part of a stamen. [AV]

Anthophyta: Within the Plant Kingdom, the division of flowering plants. [AV]

Asexual reproduction: Reproduction that does not depend on the coming together of male and female sex cells. [KR]

Awl-shaped: Short, narrowly triangular, and sharply pointed like an awl. [HJ]

Axillary bud: Buds in the axils of leaves or leaf scars.

Basal: Positioned at or arising from the base, as leaves arising from the base of the stem. [HJ]

Biennial: A plant that takes two growing seasons to go through its life cycle. [KR]

Bipinnate: Twice pinnate; with the divisions again pinnately divided. [HJ]

Bole: The main stem or trunk of a tree.

Botany: The scientific study of plants.

Branchlet: A small branch.

Bract: A modified leaf which is part of a flower.

Bryophytes: The non-vascular plants including the mosses, liverworts, and hornworts; members of the division Bryophyta. [AV]

Bud: Immature vegetative or floral shoot or both, often covered by protective scales and born on stems or twigs.

Bulb: A short, erect underground stem surrounded by fleshy modified leaves. [RA]

Canopy: The upper layer of forest, formed by interlacing branches and leaves. [KR]

Cambium: A layer of living cells in a woody plant, such as a tree, between the bark and the wood of the stem. The cambium produces phloem (to the outside) and xylem (to the inside). In dicot woody plants, the xylem makes up what we call the tree's rings.

Carpel: The female part of a flowering plant that contains the ovary. [KR]

Carnivorous plants: Those that are able to digest and absorb nutrient elements from the bodies of animals, mainly insects.

Catkin: An elongated flower cluster.

Chlorophyll: The green pigment in plants that harnesses the Sun's energy during photosynthesis. [KR]

Clasping: Term used to describe a leaf with no petiole and partly surrounding the stem.

Club mosses: Within the Plant Kindgom, primitive vascular plants of the division Lycophyta. These plants are not true mosses (which lack vascular tissue). In some species the spores are born in club-like structures.

Composite: A family of flowering plants (Asteraceae or Compositae) in which the distinctive feature is that relatively small flowers (florets) are crowded together in a dense "head". Florets come in two types: ray and disk flowers. Some species have ray flowers only, some have disk flowers only and some have both. Members of this family include daisy, sunflower, and dandelion.

Compound Leaves: Leaves consisting of two or more blades or leaflets.

Cone: The reproductive organ of conifers, in which seeds lie between protective scales. [AV]

Conifers: Vascular woody plants that bear their seeds in cones. They are usually evergreen and have needle-like leaves. Within the Gymnosperms, this is the division Coniferophyta. [KR]

Cordate: Heart shaped, in leaves, the notch is positioned at the base of the petiole. [HJ]

Corymb: A flat-topped or round-topped inflorescence, with the lower pedicels longer than the upper. [HJ]

Cotyledon: The first or "seed" leaf of a seed plant. [AV]

Cyme: A flat-topped or round-topped inflorescence in which the central flower opens first. [SR]

Deciduous: Trees which loose their leaves seasonally or at some stage of development.

Dentate: Leaves with sharp, outward-pointing teeth surrounding the entire edge. [SR]

Dicots: Flowering plants whose embryo has two cotyledons. [AV]

Dormant: Inactive, or resting. Dormancy is a stage in seeds and buds that prevents them from germinating or opening in unfavorable conditions. [GT]

Downy: Covered with short, straight, soft hairs.

Elliptic: Broadest near the middle and gradually tapering to both ends. [SR]

Entire: Leaf margins which do not have teeth or lobes.

Epiphyte: A plant that grows on the branch, stem, bark, or leaves of another plant but makes its own food.

Escaped: Spread from cultivation and now growing and reproducing without aid from man.

Fascicle: A small cluster or bundle, such as with conifer needles. [SR]

Ferns: Plants of the division Pterophyta, with leaves (fronds) often consisting of many leaflets. [AV]

Fertile: As applied to soils, rich in plant nutrients. As applied to organisms, capable of producing offspring.

Fertilization: The joining of male and female sex cells to form a new individual. [AV]

Fibrous roots: Fine, threadlike or slender roots. [RA]

Filament: The stalk of a stamen. [AV]

Fissures: Linear splits or cracks. Term commonly refers to bark or stems.

Flower: The reproductive organ of angiosperms; contains male and/or female parts. The ovules are covered by a protective tissue (the ovary).

Fronds: The leaves of ferns. Fern fronds maybe uncut (undivided), once-cut (divided into subdivisions), twice-cut (divided into subdivisions twice-the subdivisions are themselves subdivided), or thrice-cut (divided into subdivisions three times-the subdivisions of the subdivisions are also subdivided!). Thrice-cut ferns are also called lacy ferns.

Fruit: The mature ovary of a flowering plant, containing ripe seeds, plus covering tissues. [AV]

Furrowed : Deeply grooved; often used to describe tree bark.

Germination: The period when a seed or spore begins to grow. [KR]

Glabrous: Smooth, without hairs. [SR]

Glaucous: Covered with a whitish or bluish waxy coating, as on the surface of a plum. [HJ]

Globular: Globe-shaped.

Gymnosperms: Vascular plants that do not have flowers and produce naked ovules and seeds (without a covering); include conifers, cycads, and gingko. [AV]

Hastate: Arrowhead shaped leaves, but with the basal lobes turned outward rather than downward. [HJ]

Herb: A plant with aboveground stems that live for only one season (also called non-woody stems).

Herbaceous: Having non-woody stems.

Heartwood: The older, harder wood in the middle of a tree trunk that can no longer transport water up to the leaves. This wood is often saturated with decay-protecting chemicals that also make it a different color from the outer wood. [KR]

Humus: Dark brown or black partially decomposed organic matter.

Incurvate: Inwardly curved.

Infertile: Poor in plant nutrients. [GT]

Inflorescence: The arrangement of flowers on the plant stem.

Internode: A section or region of stem between nodes. [RA]

Keel: A central longitudinal ridge. [SR]

Labellum: The large central petal of an orchid, which secretes nectar. [AV]

Lanceolate: AMuch longer than wide, widest below the middle, and tapering toward the tip. [SR]

Leader: The central or primary stem of a branch or tree.

Leaf: An expanded, usually green, structure borne on the stem of a plant. Undergoes photosynthesis and transpiration.

Leaflet: a single segment or subdivision of a compound leaf.

Leaf Margin: The outer edge of a leaf.

Leaf scar: A mark on branch or twig indicating former place of attachment of petiole or leaf base. [RA]

Legumes: Plants of the pea family (Fabaceae or Leguminosae). In many species, the fruit is the distinctive "legume" or pod with rows of seeds.

Linear: Long and narrow with essentially parallel sides. [SR]

Loam: Soil composed of sand, clay and organic matter.

Lobe: A rounded projection or division of a leaf.

Mangroves: Trees that grow on the shores of river deltas, estuaries and coastlines in Subtropical to Tropical climates.

Midrib: The central conducting and supporting structure of the blade of a simple leaf or leaflet. [RA]

Monocots: Flowering plants whose embryo has only one cotyledon. [AV]

Needles or Needle-like leaves: Long, narrow leaves, similar in form to the shape of a needle.

Node: Region of stem from which a leaf, leaves, or branches arise. [RA]

Obovate: Inversely ovate, with the petiole attachment at the narrower end. [HJ]

Obovoid: Egg-shaped fruit with the narrow end attached to the stem.

Obtuse: Blunt or rounded leaf tip, with the edges of the leaf coming together at an angle greater than 90 degrees. [HJ]

Opposite: Sets of leaves arranged along a twig or shoot in pairs, with one on each side and not alternate or in whorls.

Ovoid: A three dimensional, eggshaped object (fruit).

Ovary: The part of the plant in which the female sex cells are produced. [KR]

Ovate: Egg shaped, wider below the middle (describing a leaf shape). [SR]

Ovule: Structure in flowering plants containing the female sex cell (egg) that develops into a seed after fertilization. [GT]

Palmately compound: Leaves with leaflets coming from one point at end of petiole. [RA]

Palmately veined: Leaf veins spreading out from a common point.

Panicle: A multi-branched inflorescence with flowers maturing from the bottom upwards. [HJ]

Parasite: A plant that lives on another and derives, water, nutrients and/or organic compounds from it, such as mistletoe. [KR]

Pedicel: The stalk of a single flower that is part of an inflorescence. [SR]

Peduncle: Main stalk for entire inflorescence. [RA]

Perennial: A plant that lives for many growing seasons. All trees are perennials.

Perfect flowers: Flowers possessing both the male and female reproductive organs.

Petiolate: With a petiole; term used to describe leaf attachment to stem. [RA]

Petiole: The stalk of a leaf.

Photosynthesis: The conversion of carbon dioxide and water to sugars and starches, using energy from sunlight. Oxygen is also produced as a waste product. [AV]

Pinnae: One of the divisions of a pinnately compound leaf.

Pinnate: Compound leaves arranged on opposite sides of an axis or rachis.

Pistil: The female part of a flower, which develops into seeds and fruit when fertilized. [KR]

Pocosin: A raised area of wetland.

Pollen: Minute grains, usually powdery, containing the male sex cells of gymnosperms and flowering plants. [GT]

Pollination: The transfer of pollen from an anther to a stigma (of the same or another flower). [AV]

Polygamous: Having both perfect and unisexual (flowers possessing one reproductive organ) flowers.

Pterophytes: Ferns; members of the division Pterophyta. [AV]

Pubescent: Covered with short, soft hairs. [SR]

Rachis: The axis or central line of a leaf or flower.

Raceme: An elongate, unbranched flower structure with pediceled flowers. [SR]

Resin: Semisolid or viscous substance secreted by conifer wood or bark.

Respiration: The process by which living things breakdown energy containing organic molecules in the presence of oxygen to supply energy for growth and reproduction. Respiration produces carbon dioxide as waste product. [KR]

Rhizoid: Rootlike structure that helps anchor mosses, liverworts, and fern prothalli to the ground or other surface. Some are able to absorb moisture and dissolved minerals. [GT]

Rhizome: A horizontal underground stem. [RA]

Root: The nutrient absorbing and anchoring component of plants, usually initially developed from the radicle and growing downward underground. [RA]

Runner (or Stolon): An above ground propagative stem, rooting at the tip to form new plants. [RA]

Sapwood: The younger, softer wood in a tree trunk that transports water to the leaves. [KR]

Scale: Small, often triangular, leaf or leaf-like tissue.

Scales or Scale-like leaves: Leaves in the shape of small, flat or thickened triangles.

Serrate: Leaves with forward-pointing teeth surrounding entire edge.

Sessile: without petiole; term used to describe leaf attachment to stem. [RA]

Shrub: A much-branched woody perennial plant usually without a single trunk. [RA]

Simple leaves: Leaves consisting of a single undivided blade; not compound.

Sinus: A recess, cleft or gap between two lobes.

Solitary: Occurring singly and not borne in a cluster or group, such as a solitary lily flower. [HJ]

Sori: Clusters of sporangia on the undersides of fern fronds. [AV]

Spike: An elongate, unbranched flower structure with sessile flowers. [SR]

Spine or Spine-like: A stiff, slender, sharp-pointed structure representing a modified leaf or stipule. [HJ]

Sporangia: Spore-producing structures in ferns. [AV]

Spore: A simple unit in fungi and primitive plants consisting of one or a few cells, produced either sexually or asexually, that can then grow into a new organism.

Stamen: A male part of a flower producing pollen. Stamens usually consist of the pollen-bearing anther on a stalk called the filament.

Stigma: The sticky receptive surface of the pistil, on which pollen grains germinate.

Stipule: A leafy appendage at the base of a petiole or nearby on the twig or stalk.

Stomata: A very small pore which allows water and air to enter and exit a leaf.

Style: Non-ovule-bearing portion of pistil between stigma and ovary.

Taproot: A single broad root. [AV]

Tendril: Long, slender, coiling plant organ, adapted for climbing. Formed by modification of a part of a plant, such as a stem, a leaf or leaflet. [RA]

Terminal buds: Buds found on the end of a twig.

Thorn: A sharp-pointed branch. [RA]

Transpiration: The process in which plants give off excess water into the atmosphere in the form of water vapor. [KR]

Tree: A tall, woody perennial plant usually with a single trunk. [RA]

Trifoliate: Having three leaves or three leaflets. [SR]

Umbel: An inflorescence in which individual flower stalks arise from a single point and are approximately of equal length. In a compound umbel this branching is repeated.

Understory: Trees, shrubs and other plants located beneath and in the shade of larger trees.

Vine: An elongate, weak-stemmed, often climbing annual or perennial plant, with herbaceous or woody stems. [RA]

Whorl: An arrangement of similar anatomical parts (such as leaves) in a circle around a point on an axis.

Dictionary Sources  

[AV] Alvin, Virginia, and R. Silverstein. (1996). The Kingdom of Life Plants. Connecticut: Twenty-first Century Books.

[GT] Greenway, Theresa. (2000). The Plant Kingdom: A Guide to Plant Classification and Biodiversity. Texas: Steck-Vaughn Company.

[HJ] Harris, James G., and M.W. Harris. (2001). 2nd edition. Plant Identification Terminology - An Illustrated Glossary. Utah: Spring Lake Publishing.

[KR] Kerrod, Robin. (1994). Let's Investigate Science Plant Life. New York: Marshall Cavendish.

[RA] Radford, Albert E., W.C. Dickison, J.R. Massey, C.R. Bell. (1976). Vascular Plant Systematics. New York: Harper and Row.

[SR] Smith, Richard M. (1998). Wildflowers of the Southern Mountains. Knoxville: The University of Tennessee Press.

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