Horticultural Terms

Have you ever picked up a garden book, and they began using words that seemed foreign and strange? The common gardener usually has learned by trial and error and many years of practice. Most garden books were written by individuals with PhD’s. My intention is to offer a brief selection of words that usually appear in books or instructions for gardening.

This is in no way a complete list, as professional horticulturalist has considerably more scientific terms that they use. When I first started digging deeper into learning more about a particular plant I got overwhelmed by the terms. Once the word was broken down, I was comfortable.

A

Aberrant. Unusual, or exceptional; a plant or structure that varies from customary structure or from the type; used mostly of variation.

Abundant Levels of Nitrogen Helps grow roots and shoot tissue; however, may lead to increased disease problems and reduce fruit quality.

Acariasis

Infection by mites

Acicular

Slender needle-like body, needle-like spines or bristles

Accessory buds.

Buds more than one in an axil.

Accessory fruit. Fruit-like.body composed of pericarp and other structure or structures seemingly a part of it, but not originally united with it, as wintergreen berry.

Acotyledonous. Without cotyledons.

Accrescent. Increasing; becoming larger after flowering

Accumbent. Lying against; said of cotyledons when the edges are placed against the radicle.

Abrupt Changes in Light Intensity May harm foliage.

Adventitious buds. Buds appearing on occasion, rather than in regular places and order, as those arising about wounds.

Adventitious Roots Roots arising from some plant part other than roots.

Aggregate fruit. One formed by the coherence of pistils that were distinct in the flower, as blackberry.

Alburnum. The sapwood or younger wood of a tree.

Anther Holds the pollen grains.

Angiosperms True flowering plants. Flowering plants are called angiosperms because their fruit is enclosed within a fruit.

Annual. Of one season’s duration from seed to maturity and death. Said of a body combined of flowers and fruit united into a solid mass, as in the pineapple or the mulberry.

Apical Meristem Responsible for the increase in the length of shoot tips, root tips, and buds.

Appressed Flattened against another part of the plant as in spine.

Areole(s) In cacti the specialized area from which the spines, wool or flowers rise; the cell nucleus of the plant.

Ascending Curing upwards, as in spines or flower petals

Asexual. Sexless; without sex.

Axil The area on the stem or shoot that is above where a leaf attaches.

Axillary Buds Lateral buds that occur in the area where the leaf attaches to the stem.

Axis. The main or central line of development of any plant or organ; the main stem.

B

Barb. A short point or bristle; usually employed to designate points with reflexed or fishhook-like rarely ascending appendages.

Bark. The word is often used in a general way to designate the softer outer envelope of a stem or root. In this sense, it includes all that peels readily, as the bark of the hemlock and oak, used for tanning leather. In a stricter sense, it is applied to the corky layers formed on the outer surface of woody plants. It is formed from an active layer of tissue,—the phellogen. The bark is developed in different ways on different trees. So distinct are the resulting tissues that species of trees may be readily recognized by their bark alone. Cork of commerce is the bark of the cork oak, a native of southwestern Europe. Inasmuch as the word covers so many structures, it is little used by botanists in technical descriptions.

Basin. The depression at the apex or blossom-end of an apple or other pome fruit.

Bifoliolate. With two leaflets to a leaf.

Bilobed. Two-lobed; parted into two lobes.

Bilocular. Two-celled; with two locules or compartments.

Bipartite. Divided into two parts; separated nearly to base.

Bipinnate. Twice-pinnate; when the primary divisions are pinnate.

Bipinnatifid. Twice-pinnatifid; when pinnatifid primary parts are pinnately cut.

Biplicate. Bearing two plaits or folds.

Biseptate. Twice-divided; with two partitions.

Biserial. In two series or sets.

Biserrate. Doubly serrate; the serratures themselves serrate.

Bisexual. Two-sexed; with both stamens and pistils.

Biternate. Twice-ternate; when the divisions of a ternate leaf are divided into three.

Blade. The expanded part of leaf or petal.

Blanching . A whitening or decoloring of the usually green parts of plants, as in celery or endive when it is prepared for use.

Blue and Red Light Stimulate or inhibit germination.

Botany The study of plants and all facets of their structure and physiology.

Bract. A much-reduced leaf, particularly the small or scale-like leaves in a flower-cluster or associated with the flowers.

Bracteal. Concerning or pertaining to bracts.

Bracteole. Bractlet.

Bractlet. Bract born on a secondary axis, as on the pedicel or even on a petiole.

Budding. operation of applying a single bud to the surface of the growing wood of the stock, with the intention that it shall grow. The bud is usually inserted underneath the bark of the scion, and is held in place by a bandage. Budding is a part of the general process of grafting. Called inoculation in old writings.

Bulb. A thickened part in a resting state and made up of scales or plates on a much shortened axis.

Bulbel. A bulb arising from a mother-bulb.

Bulbiferous. Bulb-bearing.

Bulblet. Aerial bulb; a bulb borne above ground, as in the flower-cluster or a leaf-axil.

C

Caducous. Falling off early, or prematurely, as the sepals in some plants.

Callus A hardened plant tissue that forms

Calyx The outer ring of the parts of the flower, a floral tube or cup

Cambium The increase in stem and root diameter or thickness is due to the growth of a lateral meristem.

Capsule A dry, dehiscent seed vessel composed of two or more parts

Carpel Pistil-cell whether pistil is one cell or several. The modified leaf in which are produced the ovules, the individual constuctive, physiological units of the plant body.

Cataphyll. An undeveloped leaf, as at the beginning of a growth.

Cephalium Wooly of bristly growth of the flowering zone formed by elongation of spines and areolar hair. Compression of growth within the cephalium zone causes its dense appearance.

Clone Genetically identical plants from a single individual and reproduced by vegetative means such as cuttings, grafts, and so on. Specific cultivar but a cultivar is not necessarily a clone because cultivars may be propagated by sexual or asexual means.

Caudicle. Little stem, stemlet; stalk of pollinium in orchids.

Common Classification Systems Growth habit, structure or form, leaf retention, climatic adaptation, use, and botanical or scientific classification.

Compound leaf. A leaf with two or more separate leaflets; in some cases (as in Citrus) some of the leaflets may be obsolete and the compound leaf have only one leaflet.

Conifers Cone-bearing plants.

Cool-Season Crops Grow best between 55 to 75 degrees.

Corm. A solid bulb-like part, usually subterranean, as the “bulb” of crocus and gladiolus.

Cotyledon. Seed-leaf; the primary leaf or leaves in the embryo; in some plants the cotyledon always remains in the seed-coats and in others (as bean) it emerges on germination.

Cross-pollination. Transfer of pollen from flower to flower.

Cuticle Waxy or varnish-like coating

D

Day Neutral Plants Not affected by amount of daylight.

Dicot Two seed leaf.

Dicot Characteristics Two seed leaf’s, flowering parts in fours or fives or multiples of those, vascular tissues arranged in concentric zones, and a netted pattern of leaf veins.

Dioecious Species in which staminate and pistillate flowers occur on separate individuals.

Deciduous Plants that lose all of their leaf’s for some period of time in the fall and winter months. Drought-Stressed Plants Light green/Grayish green

Dumose. Low and branching, as a bush.

E

Effuse. spreading; very diffuse.

Epichile. The upper part of the jointed lip of an orchid.

Epicotyl. That part of the caulicle lying above the cotyledons.

Epigeal. Cotyledons rising into the air in germination.

Epidermis Thin protective layer of cells.

Epiphyte, Air-plant; a plant growing on another or on some other elevated support.

Essential Minerals in Photosynthesis Nitrogen, Sulfur, Magnesium, and Phosphorous. They help synthesize more complex compounds needed to produce new cells.

Evergreens Plants that don’t lose all of their leaves although they cast off old leaves on a periodic basis. They are further divided into broadleaf and needle-leaved.

F

Fertile. Said of pollen-bearing stamens and seed-bearing fruits

Fertilization. Impregnation of the ovule; the act of union of sperm and egg cells, in the higher plants taking place within the ovule: fecundation.

Flagging. Wilting; said particularly of newly made cuttings and recently transplanted plants.

Flora. The plant population of a given region; also, a book describing this population.

Florets. Individual flowers of composites and grasses; also other very small flowers that make up a very dense form of inflorescence.

Floriferous. Flower-bearing.

Foliaceous. Leaf-like; said particularly of sepals and calyx-lobes and of bracts that in texture, size or color look like small or large leaves.

Foliate. In combinations, -leaved; having leaves; as trifoliate, three-leaved.

Foliolate. Having leaflets; as trifoliolate, of three leaflets.

Frond. Leaf of fern; sometimes used in the sense of foliage.

G

Gemma. A bud; particularly a bud or bud-like structure by which a plant propagates.

Gemmiparous. Bud-bearing.

Gemmule. A little bud or bud-like structure.

Grafting. The process of inserting a cion [also spelled [scion]]in a plant with the intention that it shall grow there. See Budding.

Grass Meristem Responsible for shoot growth is found near the base of the plant.

Guard Cells Pairs of specialized cells that control the opening and closing of the stomata.

Gymnosperms Conifers cycads, and ginkgo’s. These are gymnosperms because their seeds lie exposed.

Gynandrous. With the stamens grown on the pistil, forming one organ, as in the orchids.

H

Hardy Crops Plants that can tolerate some amount of short time freezing.

Heartwood The center portion of large tree limbs.

Herb. Naturally dying to the ground; without persistent stem above ground; lacking definite woody firm structure.

Herbaceous. Not woody; dying down each year; said also of soft branches before they become woody.

Hermaphrodite. Bearing both stamens and pistil in the same flower; two-sexed; bisexual.

High Concentration Hormone may induce a particular response

High Light Intensity Necessary for development of maximum color and for the best sugar and flavor in edible crops.

Hybrid. A plant resulting from a cross between two or more parents that are more or less unlike.

Hygroscopic. Capable of absorbing moisture from atmosphere.

I

Imparipinnate. Unequally pinnate; odd-pinnate; with a single terminal leaflet.

Inactive Xylem Cannot transport water and minerals.

Interfoliaceous. Between the leaves, particularly between two leaves of a pair.

Internode. The part or space of stem between two nodes or joints.

JK

Juvenility A plant from the time it is seedling until it is mature and capable of initiating flowers. Bamboo can be juvenile for 10 years.

L

Lamina. The blade of a leaf or petal or other expanded part or body.

Lateral Buds Found along the sides of stems.

Leaf Veins The continuation and termination of xylem and phloem from the roots and stems.

Leaves Provide the surface area needed for the plant to collect sunlight and conduct photosynthesis, which produces food for the plant.

Light Quality An expression of the color of the light source.

Lobe. Any part or segment of an organ; specifically a part of petal or calyx or leaf that represents a division to about the middle.

Lobule. A small lobe.

Low Concentration A hormone may induce a particular response.

M

Meristem Plant tissues in which cells divide to reproduce, grow, and develop new tissue.

Monocot One seed leaf.

Monocot Characteristics One seed leaf, flower parts in threes or multiples of threes, vascular tissues arranged in bundles, and usually parallel leaf veins.

Monoecious Plants with both staminate and pistillate flowers.

Monoclinous. Hermaphrodite; perfect; the two sexes in the same flower. See Diclinous.

Monocotyledonous. With a single cotyledon.

N

Nectary. A structure or organ that secretes nectar.

Node. A joint where a leaf is borne or may be borne; also incorrectly the space between two joints, which is properly an internode.

Nucleus. The kernel of a seed; the central denser structure of a cell.

Nucule. A small nutlet; any hard seed-like fruit or part.

Nut. An indehiscent 1-celled and 1-seeded hard and bony fruit, even if resulting from a compound ovary.

Nutlet. A small or diminutive nut; nucule.

O

Oculus. An eye; a leaf-bud when used as a cutting.

Offset. plant arising close to the base of mother plant.

Outside Layers Active Xylem, Cambium, Phloem

Ovary Contains the ovules.

P

Palmate. Lobed or divided in a palm-like or hand-like fashion.

Parasitic. Growing and living on or in another organism.

Pedicel. Stem of one flower in a cluster.

Peduncle. Stem of a flower-cluster or of a solitary flower.

Perennial. Of three or more season cycles’ duration.

Perfect flower. One that has both stamens and pistil.

Perfoliate. The stem apparently passing through the part, as a leaf; united around the stem.

Petiole Thing that attaches to the main stem.

Petal. One of the separate leaves of a corolla.

Phloem Tissue that conducts photosynthetically produced food and other compounds from the leaves to other plant parts. Materials can move up and down.

Photoperiod Dormancy in response to a specific length of daylight in a 24 hour period. Such plants are called photoperiodic.

Pinna. A primary division or leaflet of a pinnate leaf.

Pinnate. Feather-formed; with the leaflets of a compound leaf placed on either side of the rachis.

Pinnatifid. Cleft or parted in a pinnate (rather than palmate) way.

Pinnatipartite. Pinnately-parted.

Pinnatisect. Cut down to the midrib in a pinnate way.

Pinnule. A secondary pinna or leaflet in a pinnately decompound leaf.

Pip. A perpendicular or upright small rootstock used in propagation, as of lily-of-the-valley.

Pisiform. Pea-shaped; pea-like.

Pistil. The ovule-bearing and seed-bearing organ.

Pistillate. Having pistils and no stamens; female.

Plant Growth Requires a source of water, carbohydrates, chemical energy, and mineral nutrients.

Plant Metabolic Processes Gradually shut off in many species as temperatures exceed 96 F or drop below 40 F.

Pistil The principal female structure.

Pistillate Incomplete flowers that have only the female structures.

Plur-annual. Of one season’s duration only because killed by frost.

Polyadelphous. The stamens in many bundles or fascicles.

Polygamous. Bearing imperfect and hermaphrodite flowers on the same plant.

Polymerous. Of many parts or series.

Pome. Fruit of apple, pear, quince, etc.

Procumbent. Trailing or lying flat, but not rooting.

Proliferous. Bearing offshoots or redundant parts; bearing other similar structures on itself.

Proterandrous. Anthers maturing before pistils.

Proterogynous. Pistils maturing before anthers.

Pseud-annual. Perennial by means of bulbs, corms, or tubers.

Q

R

Ramification. The mode or style of branching of a plant.

Receptacle The plant part where the floral structures are attached.

Reducing Light Intensity Causes leaf drop.

Respiration Rate Doubles every 18 F between 40 F and 96 F. Occurs 24 hours a day at variable rates depending on temperature.

Root Function Take up water and soluble mineral nutrients from the soil, produce essential compounds, store excess food materials, and anchor the plant. Root Tip Meristematic area responsible for increasing root length.

Root Hairs Increase the surface area of the root system and allow it to take up water and minerals more efficiently.

Ruminated. Chewed; particularly applied to wrinkled albumen in seeds that are irregularly channeled or pierced, as in nutmeg and in Annona fruits.

Runcinate. Said of sharply lobed or cut leaves that have the segments directed backward.

Runner. A slender trailing shoot taking root at the nodes.

S

Staminate Incomplete flowers that have only the male structure.

Seed. The ripened ovule; the essential part is the embryo, and this is contained within integuments.

Seedling. A young plant raised from seed; a plant direct from seed without the intervention of grafting of any kind.

Segment. One of the parts of a leaf, petal, calyx or perianth that is divided but not truly compound.

Self-fertilization. Secured by pollen from same flower; close fertilization.

Self-pollination. Transfer of pollen from stamen to pistil of same flower; close pollination.

Sepal The small, green, leaf-like structures found at the base of flowers.

Scientific Binomial Name Consists of two parts: Genus followed by the specific epithet. Epithet is sometimes incorrectly called the species.

Shoot. A new plant from the root of the old plant; also any growing twig or axis.

Shrub. A woody plant that remains low and produces shoots or trunks from the base.

Silicle. The short fruit of certain Cruciferae.

Silique. The long fruit of certain Cruciferae.

Short Day Plants Need less than 12 hours of light to flower.

Singular Buds Occur in one plane. Alternate from one side to the other in a zigzag fashion.

Soil Water Moves passively in plant by diffusion or movement through a force gradient.

Specific Epithets They are usually adjectives and are always lowercased.

Specific Vegetative Growth Responses Seed Germination, Tuber Formation, Bulb Formation, Shoot Dormancy, Leaf Abscission, and runner and stolen development.

Spike. Compact, more or less simple indeterminate, mostly elongated cluster, with flowers sessile or nearly so.

Spikelet. A secondary spike; one part of a compound spike; particularly, one of the ultimate clusters in grosses.

Stratification Plants exposed to cold temperatures. Moist soil in order to break dormancy and germinate.

Stamen The principal male structure.

Stalk. The stem of any organ, as the petiole, peduncle, pedicel, filament, stipe.

Stamen. The pollen-bearing or “male” organ.

Staminate. Having stamens and no pistils; male.

Stipel. Stipule of a leaflet.

Stipule. A basal appendage of a petiole; the three parts of a complete leaf are blade, petiole, stipules (usually 2). Stress Could be purposely used to stunt the plant to increase its growth.

Shrubs Short, upright-growing plants with several main stems.

Stomata Tiny openings (Pores in leafs.) Succulent. Juicy; fleshy; soft and thickened in texture.

T

Tap-root. A strong nearly or quite perpendicular main root that carries the plant axis straight into the ground, all the other roots being secondary to it, rather than branching equally or diversely at the crown.

Taxonomy. Classification of species.

Tendril. A rotating or twisting thread-like process or extension by which a plant grasps an object and clings to it for support; morphologically it may be stem or leaf.

Tender Crops Plants that are killed or injured by freezing temperatures.

Terminal (Apical) Bud Found at the tips of shoots.

Translocation The movement of water, mineral nutrients, food, and other dissolved compounds from one part of the plant to another.

Transpiration The evaporative loss of water vapor from plant leaves through stomata. Helps to cool plants on hot days and serves to transport minerals from the soil and organic compounds produced in the roots to plant cells. Increases as temperature increases.

Tripinnate. Three times pinnate.

Triternate. Three times three; the leaflets or segments of a twice ternate leaf again in three parts.

Truncate. Appearing as if cut off at the end; the end nearly or quite straight across.

Tuber. A short congested part; usually defined as subterranean (as of a rootstock), although this is not essential.

Tubercle. .A small tuber, or rounded protruding body.

Tuberiferous. Tuber-bearing.

Tuberous. With or resembling a tuber or tubers.

Trees A tall plant with a single or few main stems. May be further defined according to their shape or canopies.

UVW

Unisexual. Of one sex; staminate or pistillate only.

Vascular Tissue Made up of Phloem and Xylem and usually form a continuous multi-branched system from every root tip to every shoot and leaf tip.

Vernation. The disposition or arrangement of leaves in the bud.

Vernalization Exposure to cold temperature for a period that is required before the initiation of flowers. It is the mechanism that controls flowering in biennial plants.

Vines Trail along the ground unless provided support.

Warm-Season Crops Grow best between 65 to 95 degrees.

Widow Maker A large limb or tree branch that has fractured and could fall at any time

Woody Stems The Phloem and Xylem separated by cambium.

XYZ

Xylem, Phloem, Grass Occur together in numerous vascular bundles. Scattered throughout the stem