Glossary
- Page ID
- 159959
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)| Words (or words that have the same definition) | The definition is case sensitive | (Optional) Image to display with the definition [Not displayed in Glossary, only in pop-up on pages] | (Optional) Caption for Image | (Optional) External or Internal Link | (Optional) Source for Definition |
|---|---|---|---|---|---|
| (Eg. "Genetic, Hereditary, DNA ...") | (Eg. "Relating to genes or heredity") |  |
The infamous double helix | https://bio.libretexts.org/ | CC-BY-SA; Delmar Larsen |
| Word(s) | Definition | Image | Caption | Link | Source |
|---|---|---|---|---|---|
| Zoysiagrass | A warm-season grass of fine to medium texture that turns brown with the first hard frost in the fall and greens up about mid-May. | ||||
| Xylem | Transport tissue in vascular plants, transports water from roots to stems and leaves (also transports nutrients) | ||||
| Woody plants | Perennials (life span ranges from decades to centuries, or in some cases millennia) in which the shoot (above ground portion of the plant) persists during plant dormancy (usually late-autumn to early-spring) | ||||
| Witch’s broom | deformity in a woody plant where a mass of shoots grows from a single point | ||||
| Windbreaks | Plantings of trees and shrubs placed strategically to slow winds | ||||
| Wide row planting | Planting in such closely-spaced bands rather than in rows of individual plants | ||||
| Whorled | Leaf arrangement where leaves are arranged in circles along the stem. | ||||
| Wetland | Transitional lands between terrestrial and aquatic systems where the water table is usually at or near the surface, or the land is covered by shallow water. Wetlands are those areas where water saturation is the dominant factor determining the nature of soil development and the types of plant and animal communities living in the surrounding environment. | ||||
| Well | Deep hole or shaft sunk into the earth to obtain water groundwater. | ||||
| Watersprouts | Vigorous, usually-upright shoots that grow from the trunk or branches | ||||
| Watershed | Area that drains or contributes water to a particular point, stream, river, lake or ocean. Watersheds are also referred to as basins. Watersheds range in size from a few acres for a small stream basin, to large areas of the country like the Chesapeake Bay Basin that includes parts of six states. | ||||
| Water-holding capacity | The amount of water that a soil can hold for crop use | ||||
| Water table | The depth at which soils are fully saturated with water, the upper surface of an unconfined aquifer. | ||||
| Voucher specimen | A specimen of a species that depicts clearly its most important physical characteristics and structures. | ||||
| Vine | A plant that develops long, trailing stems that grow along the ground unless they are supported by another plant or structure | ||||
| Verticutting | Vertical mowing to remove thatch buildup | ||||
| Vernalize | Cool the plant in order to encourage flowering | ||||
| Vermiculite | A sterile, lightweight, mica product used as a soil amendment | ||||
| Vermicompost | Compost made by worms as they digest plant material | ||||
| Vegetative bud | A bud that contains partially preformed leaf and stem tissue | ||||
| Vascular cambium | The main growing tissue of stems and roots in most plants. It produces the secondary xylem and secondary phloem. | ||||
| Vascular bundle | Part of the transport system in vascular plants that includes the xylem, phloem, and other tissues | ||||
| Variety | A subpopulation of a species that has a distinctive trait that distinguishes it from the rest of the species and occurs in nature | ||||
| Vacuole | A large liquid-filled cavity within a cell | ||||
| Unity | Design principle created by repetition of shapes, lines or colors, the grouping or arranging different parts of the design to appear as a single unit | ||||
| Twig | A stem that is less than one year old and has no leaves since it is still in the winter-dormant stage | ||||
| Turgor | Turgidity (swelling) and resulting rigidity of plant cells or tissues, typically from the absorption of fluid | ||||
| Turbidity | Measure of the cloudiness or opaqueness of the water expressed in nephelometric turbidity units (ntu). The turbidity is influenced by the amount and nature of suspended organic and inorganic material in water. Typically, higher concentrations of the suspended material equal greater turbidity. The source of turbidity could be sediment (fine sand, silt, and clay), organic material, particles of iron and manganese or other metal oxides, rust from corroding piping, algae, carbonate precipitates, etc. | ||||
| Tuberous stem | Shortened, flattened, enlarged, and underground stem. Examples are tuberous begonia and cyclamen. | ||||
| Tuberous roots | Underground storage organ | ||||
| Tuberous root | Modified lateral roots that are enlarged to function as an underground storage organ. Found in dahlia and sweet potato. | ||||
| Tuber | Enlarged portion of an underground stem. The tuber, like other stems, has nodes that produce buds. | ||||
| Trunk | A main stem of a woody plant | ||||
| Trowel | A small hand-tool for digging | ||||
| Trees | Perennial woody plants, usually with one main trunk and usually more than 12 feet tall at maturity | ||||
| Tree-like shrubs | Shrubs that have woodier, finely divided branches and can be pruned as a single-trunk or multi-stemmed trees | ||||
| Transpiration | Process by which a plant loses water, primarily from leaf stomata. | ||||
| Topping cuts | Height-reducing pruning cuts made indiscriminately in internode areas | ||||
| Thinning cuts | Also called reduction cuts, pruning cuts that remove branches at their points of origin or attachment | ||||
| Thermoperiod | The daily range of temperatures a plant is exposed to | ||||
| Thatch | An organic mat of stems that forms between the mineral soil and the turfgrass canopy | ||||
| Terminal buds | Buds located at the apex of a stem | ||||
| Terminal bud | Buds located at the apex of a stem | ||||
| Temperate | Perennials native to moderate temperature regions without extreme cold or a tropical climate | ||||
| Taxon | Any taxonomic group/category | ||||
| Taproot | Formed when the primary root continues to elongate downward into the soil and becomes the central and most important feature of the root system, with a somewhat limited amount of secondary branching. | ||||
| Tall fescue | A fine to moderate coarse-textured turfgrass which is tolerant of a wide range of soil types and climatic conditions | ||||
| Symptoms | Physical expressions of disease in the host tissue, e.g., changes in color, appearance, integrity, etc. | ||||
| Surface horizon | Contains more organic matter than the other soil layers. Organic matter gives a gray, dark-brown, or black color to the surface horizon | ||||
| Suckers | Vigorous shoots growing from the trunk or roots | ||||
| Subspecies | A grouping within a species used to describe geographically isolated variants | ||||
| Subsoil | Usually finer and firmer than the surface soil. Organic matter content of the subsoil is usually much lower than that of the surface layer. | ||||
| Stubble mulch | A stubble of crop residue left in place for winter | ||||
| Stress | Any change in environmental conditions that adversely affects survival, growth, development and yield in plants | ||||
| Storage leaves | Serve as food storage organs, found on bulbous plants and succulents | ||||
| Stomata | Openings in leaves that allow passage of water and gasses into and out of the leaf. Singular: stoma | ||||
| Stolon | Horizontal stem that is fleshy or semi-woody and lies along the top of the ground | ||||
| Staminate flowers | Flowers that contain stamens, but no pistils | ||||
| Stamen | The male reproductive organ. It consists of a pollen sac (anther) and a long, supporting filament | ||||
| St. Augustinegrass | A coarse-textured stoloniferous warm-season grass that has the best shade tolerance of warm-season grasses. | ||||
| Sprigs | The stems from shredded sod. Sprigs should include leaves, a stolon, and roots | ||||
| Spines | Specialized modified leaves that protect the plant | ||||
| Specific epithet | The second word of the Latin binomial that usually functions as an adjective (or sometimes named after an individual) and indicates or describes the member of the genus | ||||
| Species diversity | The use of many varied taxa (family, genus, species) within an “area”, where an area may range from a residential site to municipal or larger sites | ||||
| Species | A group of individuals that can be characterized by a set of identifiable characteristics that distinguishes them from other types | ||||
| Spading fork | Digging tool with strong, flat tines that is ideal for breaking and turning heavy soils and for loosening subsoil layers when double digging a bed | ||||
| Soluble salts | Minerals dissolved in water that can accumulate in potted plants | ||||
| Sod | Upper layer of soil with grass growing, often harvested and rolled | ||||
| Simple leaves | Leaves with a leaf blade that is a single continuous unit | ||||
| Simple fruits | Fruits that develop from a single ovary | ||||
| Silt | Relatively fine soil particles that feel smooth and floury. When wet, silt feels smooth but is not slick or sticky. | ||||
| Signs | Structures or products of the pathogen itself on a host plant, for example, mold, fungal fruiting bodies, or bacterial slime/ooze | ||||
| Shrubs | Perennial woody plants that have one or several main stems, and usually are less than 12 feet tall at maturity. | ||||
| Shovel | Tool used for digging and lifting loose soil or other materials | ||||
| Short-day | Plants that form their flowers only when the day length is less than about 12 hours in duration. | ||||
| Shoot | A young stem with leaves present | ||||
| Sexual propagation | Involves the union of the sperm (male) with the egg (female) to produce a seed | ||||
| Sepals | Small, green, leaf-like structures on the base of the flower that protect the flower bud | ||||
| Sediment | In the context of water quality, soil particles, sand, and minerals dislodged from the land and deposited into aquatic systems as a result of erosion. | ||||
| Sedges | Members of the Cyperaceae family of grass-like monocotyledonous flowering plants; distinguishable from rushes and grasses by their triangular stems | ||||
| Secondary growth | Growth in lateral meristems that causes increase in girth | ||||
| Sclerites | Hardened plates joined together forming the hard surface of insects | ||||
| Scion | In grafting, the piece of shoot with dormant buds that will produce the stem and branches on the upper portion of the graft | ||||
| Scarification | Breaking, scratching, or softening the seed coat so that water can enter and begin the germination process | ||||
| Scale | Design principle that refers to the size relationship or proportion between different parts of a landscape. This could be between buildings and plants, plants and plants, or plants and people | ||||
| Sand | Coarser mineral particles of the soil | ||||
| Rushes | Members of the Juncaceae family of flowering plants; distinguishable from grasses and sedges by their round (and frequently unbranched) stems filled with pith (not hollow) | ||||
| Runoff | Part of rainfall or snowmelt that does not infiltrate the soil but flows over the land surface toward a surface drain, eventually making its way to a stream, river, lake or an ocean. It can carry pollutants into receiving waters. Also known as stormwater. | ||||
| Runner | A specialized stem that grows on the soil surface and forms a new plant at one or more of its nodes. A type of stolon. | ||||
| Rotary tiller | Power toll with a series of rotating tines used for working soil several inches deep | ||||
| Rosulate | A circular arrangement of leaves, usually near the soil (for example, dandelion) | ||||
| Rose standard | Tree rose, a Hybrid Tea, Grandiflora, or Floribunda budded at the top of a tall trunk | ||||
| Rootstock | In grafting, the piece of shoot that provides the new plant’s root system and sometimes the lower part of the stem, the lower portion of the graft | ||||
| Root hairs | Projects of root epidermal cells, important in absorption of nutrients, plant anchorage, and more | ||||
| Root cap | Outermost tip of the root, consists of cells that are sloughed off as the root grows through the soil | ||||
| Riparian | Pertaining to the banks of a river, stream, or other typically, flowing body of water as well as to plant and animal communities along such bodies of water. This term is also commonly used for other bodies of water, e.g., ponds, lakes. | ||||
| Rhythm | Design principle of even repetition, and it directs the eye in the landscape through continuity and flow | ||||
| Rhizomes | Specialized stem that grows underground and sends out roots and shoots from nodes | ||||
| Respiration | Process by which plants use the sugars produced during photosynthesis (plus oxygen) to produce energy | ||||
| Relative humidity | The ratio of water vapor in the air to the amount of water the air could hold at a given temperature and pressure, expressed as a percent | ||||
| Rambler roses | Rose bushes that have clusters of flowers, each usually less than 2 inches across | ||||
| Rake | Tool with a long handle and crossbar with a toothed comb, helpful in spreading mulches and smoothing seedbeds | ||||
| Rain garden | A shallow landscaped depression that filters polluted stormwater before it evaporates, evapo-transpires through the plants, or percolates through the soil into the groundwater. | ||||
| Radicle | Primary root, first organ to appear when a seed germinates | ||||
| Provenance | Source of plant material | ||||
| Primocane | Raspberry and blackberry plants that bear fruits on the first year cane (shoot) which are ready for harvest in late summer | ||||
| Pregermination | Sprouting the seeds before they are planted in pots (or in the garden) | ||||
| Precocity | In grafting, the ability of rootstocks to induce fruitfulness. Precocity is measured in apple rootstocks by observing the length of time from planting to when the cultivar produces flowers. | ||||
| Precipitation | Rain, sleet, snow, or hail that falls to the earth as the result of water vapor condensing in the atmosphere. | ||||
| Pollution | Alteration of the physical, biological, chemical, and radiological integrity of water due to human activities ‚ any unwanted contaminating property that renders a water supply unfit for its designated use. | ||||
| Pollutant | Any substance of such character and in such quantities that when it reaches a body of water the effect is to degrade the receiving water perhaps to a point rendering it unfit for some specified designated use | ||||
| Pole pruners | Shears with a hooked blade above and a cutting blade beneath. The cutter is on a pole and is operated by a cord or chain pulled downward | ||||
| Point source pollution | Pollutant loads discharged at a specific location from pipes, outfalls, and conveyance channels. Point source discharges are generally regulated through the National Pollution Discharge Elimination System (NPDES) permitting procedures established by the EPA. Point sources can also include pollutant loads contributed by tributaries to the main receiving stream or river. | ||||
| Plumule | Embryonic shoot | ||||
| Plugs | Small squares/circles of sod grown in a tray | ||||
| Plant nutrition | The needs and uses of the basic chemical elements in the plant | ||||
| Plant community | The collection of plant populations found in that area | ||||
| Pistillate flowers | Flowers are those that possess a functional pistil(s), but lack stamens | ||||
| Pistil | The female part of the plant that consists of the stigma, style, and ovary | ||||
| Pinnate | Leaf shape in which leaflets are attached along an extension of the petiole | ||||
| Photosynthesis | Process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water. Generally involves the green pigment chlorophyll (in green plants) and generates oxygen as a byproduct. | ||||
| Phloem | Transport tissue in vascular plants, transports the soluble organic compounds made during photosynthesis to the rest of the plant in a process called translocation | ||||
| Phenotypic | Visual appearance as a result of DNA expression | ||||
| Petiole | Stalk that supports the leaf blade | ||||
| Petals | Modified leaves, typically brightly colored, segments of a flower’s corolla | ||||
| Pesticide | Any substance that is used to prevent, destroy, repel, or mitigate any pest. Can be synthetic (man-made), or natural products derived from plants, microorganisms, or inorganic elements | ||||
| Perlite | A sterile, porous soil amendment material produced by heating volcanic rock to approximately 1800ºF | ||||
| Perfect flower | A flower with functional stamens and pistils | ||||
| Perennial ryegrass | A fine-medium textured grass that mixes well with Kentucky bluegrass | ||||
| Perennial | Plants that live for many years. May be herbaceous or, if significant xylem develops in the stem and the top persists, may be classified as woody. | ||||
| Pendulous | Tree form in which branches hang down, also called weeping | ||||
| Peds | Peds are made up of mineral particles (clay, silt, sand) and organic matter; held together by the electrical charges on the surfaces of the minerals and organic matter | ||||
| Peat moss | Decomposed mosses and other living material found in peat bogs | ||||
| Parent material | Bottom soil horizon, decomposed rock that has acquired some characteristics of the subsoil and retained some characteristics of the rock from which it weathered. | ||||
| Parallel-veined | Leaf venation pattern in which numerous veins that run essentially parallel to each other and are connected laterally by minute, straight veinlets | ||||
| Palmate | Leaf shape in which leaflets form and radiate from a single point of attachment | ||||
| Overhead watering | Watering system in which water is sprayed down on crops, directly wetting the crop surface | ||||
| Organic matter | Plant and animal material in varying stages of decomposition present in soil. | ||||
| Organic | Methods that involve growing and maintaining healthy plants without using synthetic (manmade) fertilizers, pesticides, hormones, and other materials | ||||
| Opposite | Leaf arrangement where leaves are positioned across the stem from each other, two leaves at each node. | ||||
| Open pollinated | Seed that is self or cross-pollinated by wind or insects and is produced by isolating plants from other plants of different varieties to produce seed that is "true to type" | ||||
| Nucleus | Organelle that contains the genetic information for the organism and controls the activities of the cell | ||||
| Nonpoint source pollution | Pollution originating from diffuse sources on the landscape. Examples include runoff from fields receiving manure applications, runoff from urban landscapes, or roadbed erosion in forestry. It has been estimated that NPS pollution accounts for more than one-half of the water pollution in the United States today. | ||||
| Node | The part of the stem where one or more leaves are attached | ||||
| Net-veined | Leaf venation pattern in which veins branch from the main rib(s), then subdivide into finer veinlets which then unite in a complicated network | ||||
| Native plants | Plants that occur in the region in which they evolved. | ||||
| Nativars | Cultivars of native species | ||||
| Multiple fruits | Fruits derived from a tight cluster of separate, independent flowers borne on a single structure | ||||
| Mounding habit | Shrub growth habit in which plants often have soft, flexible stems, small leaves, and are often used in mass plantings | ||||
| Monoecious | Plants with male and female reproductive organs on the same plant | ||||
| Monocots | Grass and grass-like flowering plants with seeds that typically contain only one embryonic leaf | ||||
| Miniature roses | Rose bush 6 to 12 inches high with tiny blooms and foliage | ||||
| Micropyle | A small pore located in a seed's seedcoat that allows water absorption and gas exchange | ||||
| Micronutrients | Chemical elements required in small amounts for plant growth and development. These are: Iron (Fe), Zinc (Zn), Manganese (Mn), Boron (B), Copper (Cu), Molybdenum (Mo), Chlorine (Cl) | ||||
| Microclimates | Zones of atypical high or low temperatures | ||||
| Meristem | An area of cell division and growth Cells in the meristem can develop into all other tissues and organs found in plants. | ||||
| Mechanical/physical control | Using hands-on techniques or simple equipment/devices to reduce or prevent the spread of pest populations | ||||
| Macronutrients | Chemical elements required in large amounts for plant growth and development. These are: Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), Phosphorus (P), and Potassium (K), Calcium (Ca), Magnesium (Mg), and Sulfur (S). | ||||
| Lopping shears | Long handled shears that are operated with both hands | ||||
| Long-day | Plants form flowers only when day lengths exceed 12 hours (short nights). | ||||
| Loam | A textural class of soil that has moderate amounts of sand, silt, and clay | ||||
| Light quality | The spectral distribution of light, or the number of different colored photons emitted by the light source (for example, blues, reds, greens) | ||||
| Light intensity | Influences the manufacture of plant food, stem length, leaf color, and flowering | ||||
| Lesion | A well defined area of diseased or injured tissue, often dead spots or areas. Lesions are often a primary symptom. | ||||
| Leaf bud | Bud composed of a short stem with embryonic leaves | ||||
| Leaching | Removal of dissolved chemicals from soil caused by the movement of a liquid (like water) through the soil | ||||
| Lateral root | Side or branch root that arises from another root. Also called a secondary root. | ||||
| Lateral buds | Buds borne on the sides of a stem | ||||
| Landscape design | The process of planning and organizing the natural and man-made parts of the landscape into an aesthetic, functional, and environmentally sustainable space | ||||
| Kentucky bluegrass | Turfgrass that provides lush, blue-green, fine-bladed lawns. Best suited to areas in and west of the Blue Ridge Mountains and north of Richmond. | ||||
| Irrigation | Controlled application of water to land to supply plant water requirements not satisfied by rainfall | ||||
| Intra-specific variation | Variation within a species | ||||
| Interspecific hybrid | A cross between different species of the same genus | ||||
| Internode | Section of the stem between two successive nodes | ||||
| Intergeneric hybrid | Cross between two genera (a very rare occurrence) | ||||
| Integrated pest management | An ecosystem-based strategy that focuses on long-term prevention of pests or their damage through a combination of appropriate control tactics. These tactics can be preventative, curative, or both and are often combined to provide the best possible results. | ||||
| Inoculum | Part of a pathogen that can cause infection | ||||
| Infiltration rate | Quantity of water that enters the soil surface in a specified time interval. Often expressed as a volume per unit of soil surface per unit of time (in3 per in2 per hour). Soil surface wetness, soil texture, residue cover, precipitation rate, irrigation application, topography, and other factors control the infiltration rate. | ||||
| Infiltration | Process by which water (surface water, rainfall, or runoff) enters the soil. | ||||
| Infection | To become established on/in the plant and initiate disease development | ||||
| Hypocotyl | The portion of a seedling between the radicle and the first leaf-like structure | ||||
| Hybrid | A genetic cross of two different plants, usually from two different varieties of the same species | ||||
| Humus | The portion of organic matter that remains after most decomposition has taken place | ||||
| Host | A plant that another organism (such as an insect or virus) lives on | ||||
| Holometabolous | An insect that undergoes complete metamorphosis with four distinct stages of development | ||||
| Hoe | Tool with a blade at a right angle to the handle. Examples may be pointed with a heart-shaped blade or have a narrow blade to slice through soil. | ||||
| Herbarium | An organized and cataloged collection of such specimens, usually at a university or a museum. | ||||
| Hedge shears | Shears with long, flat blades and relatively short handles, one for each hand | ||||
| Heading cuts | Pruning cuts that reduce the height or width of a plant by cutting back lateral branches and removing terminal buds; made at nodal areas either above side branches or buds | ||||
| Hardiness | A plant’s ability to withstand low winter temperatures and remain aesthetically pleasing | ||||
| Hardening | The process of altering the quality of plant growth to withstand the change in environmental conditions which occurs when plants are transferred from a greenhouse or home to the garden | ||||
| Hand cultivators | Digging hand tool with tines | ||||
| Habitat | The area within an ecosystem where an animal is able to secure the food, water, cover and space it needs to survive and reproduce. | ||||
| Gymnosperms | Seed-bearing vascular plants that produce exposed seeds, or ovules, which are usually borne in cones | ||||
| Guard cells | Epidermal cells located around a stoma that help regulate gas exchange by opening and closing | ||||
| Groundwater | Water that fills voids, cracks, or other spaces between particles of clay, silt, sand, gravel or rock within a saturated zone or formation (aquifer) below the soil surface. | ||||
| Gradual rejuvenation | Pruning technique that removes growth gradually | ||||
| Geophytes | Herbaceous plants with underground storage organs, rather than fibrous root systems | ||||
| Genus | A group of somewhat closely related individuals (a group name) comprising one or more species | ||||
| Galls | Growth on the external tissues of a plant | ||||
| Freezing stress | Stress that occurs in plants sensitive to temperatures below the freezing point of water or 32°F | ||||
| Flower primordia | The small buds at the end of stems from which flowers develop | ||||
| Flower bud | A but that contains partially preformed flower tissue | ||||
| Floricane | Raspberry and blackberry plants that bear fruits on the second year cane | ||||
| Flooding | Temporary condition of partial or complete inundation of normally dry land areas from the overflow of inland or tidal waters or from the unusual and rapid accumulation of runoff. | ||||
| Fine-leaf fescues | Includes creeping red, hard, and chewing fescues. Exhibits the best tolerance of shade, drought, low-nitrogen, and acid soil | ||||
| Fibrous root system | Root system in which the primary root ceases to elongate, leading to the development of numerous lateral roots which branch repeatedly and form the feeding root system of the plant | ||||
| Fertilization | When materials for plant nutrition are supplied to the environment around the plant | ||||
| Fertility | The ability of soil to sustain plant growth | ||||
| Ferns | Class of herbaceous vascular plants that reproduce via spores | ||||
| Fastigiate | Tree form that looks like a narrow oval | ||||
| Extensive rejuvenation | Pruning technique that involves complete removal of the entire plant 6-10 inches above the ground | ||||
| Evaporation | Process by which a liquid is transformed to the gaseous state | ||||
| Evapo-transpiration | Water lost through stomata when they are open during the day | ||||
| Erosion | Detachment and transport of soil particles by water and wind. Sediment resulting from soil erosion represents the single largest source of nonpoint source pollution in the United States. | ||||
| Enlarged hypocotyl | Storage organ, the swollen portion of the stem below the cotyledon and above the roots | ||||
| Endosperm | Built-in food storage supply in a seed | ||||
| Edge | Places where two habitat types come together. | ||||
| Ecosystem | Biologically diverse communities, combined together with the other non-living (abiotic) elements of the surrounding environment, such as soil, water and sunlight that form a functional system of continuous energy exchange. | ||||
| Drainage | (1) the natural movement of surface water over a land area to a river, lake or ocean (surface drainage), (2) removal of water from a soil using buried pipelines that are spaced regularly and perforated (subsurface drainage). | ||||
| Disease triangle | Represents three factors that interact to produce turfgrass disease: the disease causer, the susceptible grass, and a favorable environment | ||||
| Dioecious | Plants with male and female reproductive organs on separate individuals | ||||
| Digger | Hand tool with a narrow curved or straight blade on the end of a long stick, also called an asparagus knife | ||||
| Dicots | Flowering plants with seeds that contain a pair of embryonic leaves (cotyledons). Most of the broadleaf herbs, shrubs, and trees are dicots. | ||||
| Deciduous trees | Angiosperm trees that lose their leaves in the fall | ||||
| Day-neutral | Plants that form flowers regardless of day length | ||||
| Day-length | Duration of light received. For example, Poinsettia, kalanchoe, and Christmas cactus bud and flower only when day-length is short (11 hours of daylight or less). | ||||
| Cutting | A vegetative plant part which is severed from the parent plant in order to regenerate itself, thereby forming a whole new plant | ||||
| Cuticle (insects) | The outer covering of the insect, includes most of the material of the exoskeleton | ||||
| Cuticle | Protective film covering the outermost layer of epidermis in leaves, some shoots and some other plant organs. | ||||
| Cultural Control | Modifying or disrupting the pest environment to make it less habitable for a pest | ||||
| Cultivar | Variety bred by people to have desired traits that are reproduced in each new generation (usually through asexual propagation) | ||||
| Crowns | Region of compressed stem tissue from which new shoots are produced, generally found near the surface of the soil | ||||
| Crown | A region of compressed stem tissue from which new shoots are produced | ||||
| Cotyledons | Modified leaves that are found on the embryonic plant and commonly serve as storage organs | ||||
| Corolla | The petals of a flower | ||||
| Corms | A solid, swollen stem whose scales have been reduced to a dry, leaf-like covering. They have shapes similar to bulbs, but do not contain fleshy scales. | ||||
| Cork spot | Small dimples on the surface of apples, likely caused by lack of calcium availability in the developing fruit | ||||
| Cork cambium | Falls outside the vascular cambium and is responsible for growth that replaces the epidermis in stems and roots. | ||||
| Contaminants | Undesirable substance not normally present, or an usually high concentration of a naturally-occurring substance, in water, soil, or other environmental medium. In more restricted usage, a substance in water that may be harmful to human health. | ||||
| Conservation landscaping | Landscape principles that apply best practices for conserving water, soil, and existing native plant communities. | ||||
| Conifers | Gymnosperms, mostly evergreen but there are notable deciduous species, that have needle, scale-like, or awl-like foliage | ||||
| Compound leaf | Leaf composed of several separate leaflets arising from the same petiole | ||||
| Complete flower | A flower with a stamen, pistils, petals, and sepals | ||||
| Columnar | Column-like tree form | ||||
| Cold stratification | Process where seeds are exposed to a period of cold temperatures to break their dormancy cycle | ||||
| coconut coir | A pH-neutral, non-hydrophobic soil amendment that aerates and improves water retention of soil. Readily renewable and more environmentally friendly than peat moss | ||||
| Clones | Groups of plants that are identical to their one parent and that can only be propagated asexually | ||||
| Climbing roses | Rose bushes that have flowers more than 2 inches across, borne on wood that is 2 or more years old. Canes are larger and sturdier than those of ramblers | ||||
| Clays | The finest soil particles | ||||
| Chlorosis | Yellowing of normally green tissue | ||||
| Chloroplasts | Sites of photosynthesis within cells that contain chlorophylls and carotenoid pigments | ||||
| Chitin | The primary component of the exoskeletons of arthropods such as crustaceans and insects | ||||
| Chilling stress | Stress that occurs in plants sensitive to temperatures in the range of 68-32° F | ||||
| Chemical control | Use of pesticides to reduce pest populations. A pesticide is any substance that is used to prevent, destroy, repel, or mitigate any pest | ||||
| Chelates | Chemical claws that help hold metal ions, such as iron, in solution, so that the plant can absorb them | ||||
| Cerci | Typically paired appendages on the abdomen of many species of insect, typically with sensory function | ||||
| Centipedegrass | A coarse-textured stoloniferous warm-season grass that is adapted in southern Virginia from Martinsville to the coast. It is the lowest maintenance, highest density warm-season grass available. | ||||
| Cell wall | A rigid, structural layer outside the cell membrane in cells of plants, fungi, and some other organisms | ||||
| Cation exchange capacity | A measure of the total negative charges within the soil that adsorb plant nutrient cations | ||||
| Cataphylls | The small, leathery, protective leaves that enclose and protect buds, found on rhizomes and are | ||||
| Caneberries | Fruits that grow on woody stems called canes, for example, raspberries, blackberries, and their hybrids | ||||
| Cane habit | Shrub growth habit in which plants spread by sending up erect new branches, called canes, from their base | ||||
| Cane | A stem that has a relatively large pith (the central, strength-giving tissue of stem) and usually lives only one or two years | ||||
| Cambium | In woody plants, the layer of cells located between the wood and bark of a stem from which new tissues originate | ||||
| CAM plants | Found in very hot dry desert areas. Like C4 plants, CAM plants are not susceptible to photorespiration because, unlike C3 and C4 plants, they open their stomata at night, thus conserving water and fixing CO2 and storing it for use during the day to make sugar. | ||||
| Calyx | The sepals of a flower | ||||
| C4 plants | Found in hot, dry, subtropical to tropical environments. They are fast growers and have higher rates of photosynthesis than C3 plants. Because C4 plants do not photorespire, they are more efficient in fixing CO2 than C3 plants. | ||||
| C3 plants | Found in temperate to cold climates with high moisture environments and represent the majority of plant species. They typically are slower-growing plants than C4 plants and use CO2 less efficiently as a result of an energy-wasting process called photorespiration. | ||||
| Bypass pruners | Pruning shears with two blades that cut like scissors | ||||
| Bulbs | Shortened, compressed, underground stems surrounded by fleshy scales (leaves) that envelop a central bud located at the tip of the stem | ||||
| Budding | The union of one bud and a small piece of bark from the scion with a rootstock | ||||
| Bud | Small package of partially preformed tissue which becomes leaves/stems or flowers | ||||
| Broadleaf evergreens | Angiosperms trees that retain foliage throughout the year | ||||
| Branch collar | The swollen area that forms around the base of a branch, often appearing a bit swollen | ||||
| Branch bark ridge | Prominent ridge of raised bark that forms within the branch crotch | ||||
| Branch | A stem that is more than one year old and typically has lateral stems | ||||
| Bracts | Modified leaf or scale with a flower or flower cluster in its axil. Often brightly colored, as in poinsettias. | ||||
| Bolt | flower prematurely | ||||
| Blade | Expanded, thin structure on either side of the midrib of a leaf. The blade is usually the largest and most conspicuous part of a leaf. | ||||
| Biotic | Living agents such as fungi, nematodes, bacteria, and viruses | ||||
| Biological control | Using living organisms (i.e., natural enemies) to reduce pest populations (typically insects and weeds) | ||||
| Biodiversity | The variety of genes, species and ecosystems in the aggregate, across the larger landscape. | ||||
| Binomial nomenclature | System of naming organisms in which the name is composed of two terms | ||||
| Biennials | Plants that start from seeds and produce vegetative structures and food storage organs the first season and flowers, fruit, and seeds the second season | ||||
| Bermudagrass | A fine-bladed, warm-season grass with exceptional drought tolerance that aggressively creeps by both rhizomes and stolons. | ||||
| bedding plants | Encompass a wide variety of non-hardy, seasonal things like annuals, tropicals, herbs, vegetable transplants, etc. | ||||
| Bark | A nontechnical term that refers to all the tissues outside the vascular cambium, including the periderm | ||||
| Bare root plants | Perennials that are dug up during their dormant season and sold without soil around the roots | ||||
| Balance | Design principle that refers to an aesthetically pleasing integration of elements; a sense of one part being of equal visual weight or mass to another | ||||
| Axillary buds | Buds arising in the leaf axils | ||||
| Autotrophy | Ability of plants to manufacture their own food | ||||
| Atmospheric humidity | Amount of water vapor in the air, expressed as a percentage of the moisture saturation of air | ||||
| Aquifers | Geologic formation that holds and yields usable amounts of water. The water in an aquifer is called groundwater. Aquifers may be categorized into confined aquifers and unconfined aquifers. | ||||
| Anvil style shears | Pruning shears with a sharpened blade that cuts against a broad, flat plate | ||||
| Annuals | Plants that pass through their entire life cycle from seed germination to seed production in one growing season, then die | ||||
| Angiosperms | Flowering plants that produce seeds enclosed in a fruit | ||||
| Ametabolous | An insect that undergoes slight or no metamorphosis | ||||
| Alternate | Leaf arrangement where leaves are arranged in alternate steps along the stem with only one leaf at each node. | ||||
| Aggregate fruits | Fruits that come from a single flower with many ovaries | ||||
| Adventitious buds | Buds arising at sites other than in the terminal or axillary position | ||||
| Adsorption | Attachment of dissolved or gaseous pollutants to the surface of solids. For example, odors from freezers and refrigerators are adsorbed to baking soda. | ||||
| Accent | Focal point, something that deliberately stands out from the overall landscape | ||||
| Absorption | Process by which substances, particularly water and minerals, are moved into the plant. This occurs mainly through the roots in the tip region where root hairs are present, but it may also occur through leaf surfaces. | ||||
| Abiotic factors | Nonliving factors such as nutrient deficiencies and water or temperature stress |