Foundation seed. Seed stock handled to most nearly maintain specific genetic identity and purity under supervised or approved production methods certified by the agency.

Frost pocket. A depression in the ground into which cold air drains but from which it cannot escape, thus causing it to be an area very subject to freeze injury.

Fruit. An expanded and ripened ovary with attached and subtending reproductive structures. Genes. Basic units of hereditary material that dictate the characteristics of individuals.

Germination. The initiation of active growth by the embryo, resulting in the rupture of seed coverings and the emergence of a new seedling plant capable of independent existence.

Grafting. The joining of two separate structures, such as a root and stem or two stems, so that by tissue regeneration they form a union and grow as one plant

Growing season. The period from the last spring freeze until the first freeze in the fall. In the United States this ranges from about 100 to 365 days.

Hardening. The result of many changes that occur in a plant as it develops resistance to adverse conditions, especially cold.

"Hardening off." The treatment of tender plants to enable them to survive a more adverse environment. Treatments involve withholding nutrients, lowering temperatures, allowing temporary wilting, and other methods to slow growth rate.

Hardpan. A layer in the soil that cannot be penetrated and which restricts root penetration as well as movement of air and water.

Hardwood cuttings. Cuttings made from woody deciduous species and narrow-leaved evergreen species, such as grape and hemlocks.

Heading back. Type of pruning cut where the end portion of the shoot is removed but the portion at the base is not.

Herbaceous cuttings. Cuttings made from herbaceous plants (see definition below), such as chrysanthemums, coleus, and geraniums.

Herbaceous perennials. Plants with soft, succulent stems whose tops are killed back by frost in many temperate and colder climates, but whose roots and crowns remain alive and send out top growth when favorable growing conditions return.

Herbarium. A collection of plant specimens that have been taxonomically classified, pressed, dried, and mounted on a sheet of herbarium paper.

Horticulture. The intensive cultivation of plants.

Humus. A dark-colored organic material that is the product of organic matter breakdown by both microorganisms and chemical reactions.

Hybrid. In its simplest form, a first-generation cross between two genetically diverse parents. Imperfect flower. Flower lacking either the stamen or the pistil.

Incomplete flower. Flower lacking one or more of the fours sets of floral parts.

Indehiscent. Type of dry fruit in which the fruit wall does not split at any certain point or seam at maturity. Indeterminate growth. Growth that is potentially limitless.

Inflorescence. The arrangement of the flowers on the floral axis-a flower cluster.

Interstock. Intermediate stem piece that is grafted between the upper and lower pars of the graft.

Landscape design. The profession concerned with the planning and planting of outdoor space to secure the most desirable relationship between land forms, architecture, and plans to best meet human needs for function and beauty.

layering. A vegetative method of propagation that produces new individuals by producing adventitious roots (roots growing from unusual places) before the new plant is separated from the parent plant.

Leaching. The downward movement of nutrients or salts through the soil profile in soil water. Leaching accounts for nutrient losses but can also be beneficial in ridding a soil of excess salts.

Leaf arrangement. The arrangement of leaves on the stem.

Leaf-bud cuttings. Cuttings consisting of a leaf blade, leaf stalk, and a short piece of the stem. Leaf cuttings. Entire leaves with or without the leaf stalks.

Leaflets. Individual parts of a compound leaf.

Leaves. Vegetative plant parts that are lateral outgrowths of stems that have developed special structures for photosynthesis.

Legume. A simple, dry, dehiscent (see definition of dehiscent) fruit with one locale that splits along two seams.

Lime. Ground limestone that is used to raise soil pH.

Malling-Merton series. A group of apple rootstocks that were the result of the crossing the Malling series with the 'Northern Spy' to add resistance to woolly aphids.

Market gardening. The growing of an assortment of vegetables for local or roadside markets. Mesocarp. The center portion of the fruit wall.

Micronutrient. An essential nutrient that is needed in small amounts; also called a trace or minor element. Monoecious. Plants that produce male and female flowers on the same plant.

Mound or stool layering. A layering procedure in which the new shoots develop in spring and soil is mounded around their bases, excluding light and enhancing root formation.

Mulch. A material applied to the surface of a soil for a variety of purposes such as conservation of moisture, stabilization of soil temperature, and suppression of weed growth.

Nursery grower. A person who produces or distributes ornamental plants.

Nut. An indehiscent dry fruit similar to the achene except that the fruit wall is hard throughout. Offsets. Miniature bulbs grown to full size.

Offshoots. Short, horizontal stems that occur in whorls or near whorls at the crown of stems.

Olericulture. The study of vegetable production.

Opposite leaves. Leaves arising from opposite sides of the same node.

Organic matter. Materials rich in carbon of either plant or animal origin, which exist in all stages of decomposition of soils.

Ovary. Part of the pistil that contains one or many small bodies known as ovules. Ovule. The immature seed in the ovary.

Palmate leaf. A compound leaf with all the leaflets arising from one point at the end of the leaf stalk

Palmately veined leaves. Leaves with netted veins having several large veins radiating into the blade from the leaf stalk at the level where the leaf stalk and blade join.

Panicle. Type of flower cluster with either a cluster of racemes or corymbs (see definitions), distinctly branched.

Pepos. Berries that have a hard rind around the fruit.

Perennials. Plants that do not die after flowering but live from year to year.

Perfect flower. A flower that has both a pistil (or pistils) and stamens but may lack sepals, petals, or both. Perianth. Structure consisting of the sepals and petals.

Pericarp. The fruit wall, consisting of three distinct layers; the exocarp, the mesocarp, and the endocarp.

Pest management. The control of a pest or group of pests by a broad range of techniques from biological control to pesticides. The goal is to keep damage below economic levels without completely eliminating the pest.

Petals. Structures collectively making the corolla, which protect the inner reproductive structures and often attract insects by either their color or their nectar and thus facilitate pollination.

Petiole. The leaf stalk.

pH. A measure of acidity or alkalinity, expressed as the negative log of the hydrogen ion concentration. A pH of 7 is neutral; less than 7 is acidic more than 7 is basic

Pinching. Breaking off the uppermost growing point, thus allowing the willary buds to start to grow. This promotes outward growth rather than upward growth.

Pinnate leaf. A compound leaf with the leaflets arranged along both sides of the midrib.

Pinnately veined leaves. Leaves with netted veins where secondary veins extend laterally from a single midrib.

Pistil. The female reproductive organ, consisting of the stigma, style, and ovary. Plant growth. A permanent increase in volume, dry weight, or both

Plant pathogen. A microorganism that causes a plant disease.

Plant propagation. Increase in numbers or perpetuation of a species by reproduction.

Pome. Type of fruit in which the portions produced by the pericarp are enclosed within fleshy parts that are derived from parts of the flower other than the ovary. An apple is a pome.

Pomology. The study of fruit production.

Pot-bound. Having restricted root growth and a circular pattern of root growth caused by a too-small container.

Rest. A state of suspended growth or outwardly visible activity due to internal physiological factors. Also referred to as physiological dormancy.

Rhizome. Horizontal stems that grow underground. They serve as storage organs and a means of vegetative reproduction.

Root. Vegetative plant part that anchors the plant, absorbs water and minerals in solution, and often stores food.

Root cuttings. Cuttings 5 to 15 cm long made from root sections in the fall or winter.

Runner. A slender stolon (see definition) with elongated internodes. These root at the nodes that touch the ground. Example: strawberries.

Rust. A type of fungal disease that requires two hosts. For example, White Pine Blister Rust alternates between white pine and Ribes sp. Gives a rusty appearance to the plant.

Samara. An indehiscent dry fruit with either one or two seeds, in which pericarp bears a flattened wing-like outgrowth. The "helicopters" of the maple trees are double-samaras.

Scales. Modified leaves that protect structures.

Scaling. A type of propagation that separates bulb scales from the mother bulb to induce the formation of bulblets.

Scarification. The chemical or physical treatment given to some seeds to break or weaken the seed coat sufficiently for germination to occur.

Scion (cion). The upper part of the union of a graft.

Seed. Plant embryo with associated stored food encased in a protective seed coat.

Self-pollination. The process by which pollen is transferred from the pollen producing section of the plant to the pollen receiving part of the plant of the same flower or another flower of the same cultivar.

Semihardwood cuttings. Cuttings made from woody, broad-leaved evergreen species such as ligustrum and holly.

Sepals. Structures that usually form the outermost whorl of the flower; collectively, the calyx.

Separation. The use of bulbs and corms in propagation that utilizes the naturally detachable parts.

Serrate leaf. A leaf with serrations or "teeth" along the edge of the leaf.

Sessile. Without a petiole (as in some leaves), or without a pedicel (as in some flowers and fruits).

Simple layering. A method similar to tip layering, except that the stem behind the end of the branch is covered with soil and the tip remains above ground.

Simple leaves. Leaf blades consisting of one unit.

Sinus. The indentation of a leaf. Sinuses alternate with lobes.

Slow-release fertilizer. A fertilizer that is made by coating the particles with a wax or other insoluble or very slowly soluble material to provide a predictable, slow release of the encapsulated materials.

Softwood cuttings. Cuttings taken from soft, succulent, new spring growth of deciduous or evergreen species of woody plants.

Soil. The outer, weather layer of the earth's crust that has the potential to support plant life. Soil is made up of inorganic particles, organic matter, microorganisms, water, and air.

Soil management. The practices used in treating a soil, which may include various types of tillage and production systems.

Soil structure. The arrangement of individual soil particles.

Spike. Flower cluster of an indeterminate (unlimited number) raceme of sessile flowers attached to the floral axis with the oldest flowers at the base.

Spikelet. Diminutive type of spike inflorescence found in grasses.

Spines. Sharp-pointed woody structures, usually modified from a leaf or part of a leaf.

Stamen. Part of the flower consisting of the anther, in which pollen is produced, and a slender filament that holds the anther in a position favorable for pollen dispersal. Male reproductive organ.

Staminate flower. Flower in which only the stamens (male reproductive parts) are present; there are no pistils (female reproductive parts).

Stigma. The pollen-receiving site of the pistil.

Stipules. Leaflike appendages often found on either side of the base of the petiole; they may subtend the leaf, but they are not actual parts of the leaf.

Stock (rootstock). The lower part of a graft.

Stolon. An aboveground stem that reclines or becomes prostrate and may form roots at the nodes that may come into contact with the ground.

Stratification. The storing of seeds at low temperatures under moist conditions to break physiological dormancy or rest.

Succulent leaves. Water storage structures characteristic of plants in and and semiarid regions.

Taproot. Primary root that persists and maintains its dominance.

Tendrils. Slender, twining leaf modifications used for support, as in the terminal leaflets of the grape.

Terminal buds. Large and vigorous buds at the tips of stems, responsible for terminal growth.

Thorn. A short, sharp-pointed branch.

Tip layering. Layering in which rooting takes place near the tip of the current season's shoot, which naturally falls to the ground.

Tissue culture. The growing of masses of unorganized cells on agar or in liquid suspension. Useful for the rapid asexual multiplication of plants.

Topworking. Grafting procedure by which branches of trees are changed to a more desirable cultivar.

Trickle irrigation. The application of small quantities of water directly to the root zone through various types of delivery systems on a daily basis.

True leaves. The first leaves to emerge after the germination of a seed.

Tubers. Enlarged underground stems serving as storage organs of starch or related materials. Potatoes are tubers.

Twig. Stem, 1 year old or less, without leaves.

Umbel. Type of flower cluster in which the pedicels arise from a common point and are about equal in length.

Variegated. Leaves with green and white striped pattern instead of the typical all-green look.

Vegetable. The edible portion of an herbaceous garden plant.

Weed. A plant growing where it is not wanted.

"Wet feet." A condition where plants are exposed to excess soil moisture caused by flooding or a high water table.

Whorled arrangement. Three or more leaves at a node.

Wilt. Loss of rigidity and drooping of plant parts caused by many different plant diseases. Generally, it involves an interference with water conduction inside the stems.

Woody perennials. Plants with woody fiber.