Plant Science Terms - C

Calcium carbonate - compound found in limestone, ashes, bones, and shells; the primary component of lime

Callus - tissue that forms over wounds

Calorie - amount of heat required to raise the temperature of 1 cubic centimeter of water 1°C

Calyx - entire set of sepals on a flower. The highly colored portions of the flower that protect the inner reproductive structures. Often attract insects with their color or may contain osmophores which are scent structures (both of which facilitate pollination)

Canker - fruiting bodies that develop in a area below the bark and break through the surface in a sharply defined area on woody plant part

Crassulacean Acid Metabolism (CAM) - allows plants to keep their stomata closed during the hot part of the day to prevent water loss. These plants can open their stomata at night and save the collected carbon dioxide for the next day when sunlight is available

Cambium - layer of meristematic tissue that produces new phloem on the outside, new xylem on the inside, and is the origin of all secondary growth in plants. The cambium layer forms the annual ring in wood

Candelabrum - strong, dominant rose cane with accelerated growth that originates from a bud union and explodes with many blooms

Candle - on a pine tree, new terminal growth from which needles emerge

Canes -  externally woody, internally pithy stem of a bramble or vine; previous season's growth from the arms or trunk of a grape plant or, the supporting part of the raspberry plant, similar in function to the trunk of a tree 

Canker - plant lesion where part of the plant quits growing and the surrounding parts continue to grow. Sunken, discolored, dead areas on twigs or branches, usually starting from an injury, wound, or pathogen

Canopy - top branches and foliage of a plant; shape-producing structure of a tree or shrub

Capillary action - force by which water molecules bind to the surfaces of soil particles and to each other, thus holding water in fine pores against the force of gravity

Capitulum - dense, short, compact cluster of sessile flowers, as in composite plants or clover.; very dense grouping of flower buds, as in broccoli

Capsule - simple, dry, dehiscent (see definition of dehiscent) fruit with two or more locules (the cavities of the ovary of the pistil of a flower) which split in various ways

Causal organism - organism (pathogen) that produces a given disease

Caterpillar - see larva

Catfacing - disfigurement or malformation of a fruit. Fruits typically affected include tomatoes and strawberries. Catfacing is caused by insects or adverse weather during fruit development, as well as other unknown factors

Cation - positively charged ion. Plant nutrient examples include calcium and potassium. (See also Anion)

Cation Exchange Capacity (CEC) - measure of how much fertilizer your soil can hold and release over time.  A high CEC is good because it means your soil will hold a lot of fertilizer ( a storehouse of reserve nutrients).  Clay soils have high CEC.  A low CEC means you will have to fertilize more often.  Sandy soils have low CEC

Catkin - type of spike arrangement of flowers on the floral axis that has unisexual flowers made up of sepals and petals

Cell - structural, functional unit of a plant

Central leader - trunk or stem extending up through the axis of a tree or shrub and clearly emerging at the top. (2) A system of pruning that uses the central leader as a basic component. (See also Leader)

Cercus (Cerci plural) - threadlike or sometimes forceps-like tail near the tip of an insect’s abdomen (usually a pair) which are used to help them sense and detect their environment

Certified seed - progeny of registered seed stock. It is the final stage in the expansion program and is certified with a metal seal and blue tag

Chelate - complex organic substance that holds micronutrients, usually iron, in a form available for absorption by plants

Chemical insect control - use of chemicals, or insecticide, to control insect populations

Chilling injury - description of plant damage to tropical and sub-tropical species, caused by temperatures that are cold but not freezing, generally ranging from 33 to 59°F. This includes certain horticultural products like banana, papaya, cucumber, and sweet potato

Chilling requirement - cold period required by certain plants and plant parts to break physiological dormancy or rest. The chilling requirement is expressed in terms of the required number of hours at 7 degrees centigrade or less

Chimera - plant or plant part that is a genetic mixture of two or more genetically different types of cells

Chlorophyll - green pigment in plants responsible for trapping light energy for photosynthesis

Chloroplast - specialized component of certain cells. Contains chlorophyll and is responsible for photosynthesis

Chlorosis - yellowing or whitening of normally green tissue, due to a lack of chlorophyll

Chlorotic - yellow

Chitinous. Chitin - tough, semitransparent substance that is the main component of the exoskeletons of arthropods, such as the shells of crustaceans and the outer coverings of insects. Chitin is also found in the cell walls of certain fungi and algae. Chemically, it is a nitrogenous polysaccharide (a carbohydrate)

Cistern - reservoir, tank, or container for storing or holding water or other liquid

Clay - smallest type of soil particle (less than 0.002mm in diameter)

Clay Soil - soil composed of many tiny plate-like soil particles that can compact with time to form a hard, solid mass that makes shoveling difficult, digging holes more laborious, and often results in poor drainage

Cleft - incisions extend more than halfway to the midrib

Climber - plant (particularly vines) that climbs on its own by twining or using gripping pads, tendrils, or some other roots or stem structures to grip or attach itself to a structure or another plant. Plants that must be trained to a support are properly called trailing plants, not climbers

Cloche - plastic, glass, or Plexiglas plant cover used to warm the growing environment and protect plants from frost

Clone - plant group whose members have all been derived from a single individual through constant propagation by vegetative (asexual) means, e.g., by buds, bulbs, grafts, cuttings, or laboratory tissue culture

Clump Forming - plant that form clumps of foliage, often spreading to form other clumps close by

C:N ratio - ratio of carbon to nitrogen in organic materials. Materials with a high C:N ratio (high in carbon) are good bulking agents in compost piles, while those with a low C:N ratio (high in nitrogen) are good energy sources

Cohesion - sticking together of like molecules. Cohesion allows water to form drops

Cold composting - slow composting process that involves simply building a pile and leaving it until it decomposes. This process may take months or longer. Cold composting does not kill weed seeds or pathogens

Cold frame - plastic-, glass-, or Plexiglas-covered frame or box that relies on sunlight as a source of heat to warm the growing environment for tender plants

Cold storage - type of insulated storage utilizing mechanical refrigeration to maintain a stable, cold temperature for long-term storage

Cole crops - group of vegetables belonging to the cabbage family; plants of the genus Brassica, including cauliflower, broccoli, cabbage, turnips, and Brussels sprouts

Coleoptera - major order of insects that have two pairs of wings, or are wingless, and chewing mouthparts (beetles, weevils)

Collar - swollen area at the base of a branch where it connects to a trunk. Contains special tissue that prevents decay from moving downward from the branch into the trunk. The place to make a proper pruning cut. (See also Shoulder ring)

Collembola - major order of hexapods that are wingless and have chewing mouthparts (springtails)

Commercial floriculture - area of horticulture that includes the commercial production and distribution of cut flowers, flowering pot plants, foliage plants and bedding plants

Compaction - pressure that squeezes soil into layers that resist root penetration and water movement. Often the result of foot or machine traffic

Companion planting - practice of growing two or more types of plants in combination to discourage disease and insect pests

Compatible - different varieties or species that set fruit when cross-pollinated or that make a successful graft union when inter-grafted. (See also Pollinizer)

Complementary - in landscaping, use of opposite colors on the color wheel such as red and green, orange and blue, and yellow and violet

Complete fertilizer - fertilizer that contains all three macronutrients [nitrogen (N), phosphorus (P), potassium (K)]. Examples of commonly used fertilizers are 10-10-10, 16-4-8, and 12-4-8

Complete flower - flower composed of a short axis or receptacle from which arise four sets of floral parts-sepals, petals, stamens, and pistils

Complete metamorphosis - type of insect development in which the insect passes through the stages of egg, larva, pupa, and adult. The larva usually is different in form from the adult. (See also Simple metamorphosis)

Compost - soil-like substance high in organic matter created by the breakdown of organic waste (decomposition) under conditions manipulated by humans. It is an excellent fertilizer used to improve both the texture and fertility of any soil. (See also Humus)

Compound bud - more than one bud on the same side of a node. Usually, unless growth is extremely vigorous, only one of the buds develops, and its branch may have a very sharp angle of attachment. If it is removed, a wider angled shoot usually is formed from the second (accessory) bud. Ashes and walnuts are examples of plants that typically have compound buds

Compound leaf - leaf with the blade divided into several leaflets or sections

Compound umbel - type of flower structure in which a series of simple umbels (see definition of umbel) arise from the same point on the main axis

Conifer - cone-bearing tree or shrub, usually evergreen. Pine, spruce, fir, cedar, yew, and juniper are examples

Conk - tough, often shelf-like (bracket) fungal fruiting body emerging from standing, fallen, or buried wood. Sign of wood decay in progress because it forms on rotting woody plants

Contact herbicide - chemical that will harm a plant when it comes into contact with green plant tissue

Container Plant Style - plants used in combinations are sometimes classified as thrillers, fillers and spillers to identify what role each plant fulfills in a combination design.  Container plant style identifies this designation

Controlled Release Fertilizer - fertilizer in pellets form and is an improved version of Slow Release Fertilizer.  Fertilizer is released based on soil temperature itself (not microbe action) and tends to be more exact than Slow Release Fertilizer. Also called Time Release Fertilizer

Cool-Season Grass - grasses that put on most of their growth in spring before temperatures begin exceeding 75 degrees Fahrenheit and in the fall when temperatures cool down to no lower than 60 degrees Fahrenheit. They generally maintain good color through the summer but won't grow much when it is hot 

Cordate - heart-shaped or broadly ovate; tapering to an acute apex, with the base turning in and forming a notch where the petiole is attached

Cordon - method of espaliering fruit trees, vines, etc., to horizontal, vertical, or angled wire or wooden supports so the maximum branch surface is exposed to the sun, resulting in maximum fruit production; branch attached to such a support

Coriaceous - leaf textures that are leather-like and tough

Coring - see Aerification

Cork cambium - on woody plants, the layer of cells that produces bark, or cork, located just below the bark layers

Corm - short, fleshy, below ground stem that is solid, swollen, and covered with reduced, scale-like leaves with few nodes and very short spaces between nodes (for example, Gladiolus and crocus)

Cormel - small, underdeveloped corm, usually attached to a larger corm

Cornicle - short, blunt horn or tube (sometimes button like) on the top and near the end of an aphid’s abdomen. Emits a waxy liquid that helps protect against enemies

Corolla - part of a flower; all of the petals together 

Cortex - tissue in roots and stems immediately inside the epidermis

Cortex cells - found beneath the epidermis, these cells help move water from the epidermis and are active in food storage

Corymb - usually flat-topped (raceme) flower cluster in which the individual flower stalks (pedicels) grow upward from various points on the main stem to approximately the same level resulting in a flat-topped flower cluster

Cotyledon - seed leaf that is a food storage structure in seeds; the first leaf from a sprouting seed. Monocots have one cotyledon, dicots have two

Cover crop - crop planted to protect the soil from erosion; crop planted to improve soil structure or organic matter content

Crawler - early stage of insect development (nymph) that is mobile

Creeping growth habit - plant development at or near the soil surface that results in lateral spreading by rhizomes, stolons, or both

Crenate - having rounded teeth

Crop rotation - practice of growing different types of crops in succession on the same land chiefly to preserve the productive capacity of the soil by easing insect, disease, and weed problems

Crop seed - any seed grown for profit, often including undesirable grassy weeds, such as orchard grass

Cross-pollination - fertilization of an ovary on one plant with pollen from another plant, producing an offspring with a genetic makeup distinctly different from that of either parent. Specifically, pollen is transferred from an anther of one flower to the stigma of a second flower of a different cultivar (See also Pollinizer)

Crotch angle - angle formed between a trunk and a main scaffold limb. The strongest angles are 45 to 60°

Crown - collectively, the branches and foliage of a tree or shrub; thickened base of a plant’s stem or trunk to which the roots are attached.; compressed aboveground stems as occurs in grasses. The portion of a grass plant that includes the stem apex, un-elongated internodes, and lower nodes from which secondary roots begin

Crown gall - specific disease caused by the bacterium Agrobacterium tumefaciens that causes excessive, undifferentiated growth that may girdle roots, stems, or branches

Cultipack - firm and pulverize (a seedbed) with a corrugated roller

Cultivar - plant derived from a cultivated variety of a species that has originated and persisted under cultivation, not necessarily referable to a botanical species, and of botanical or horticultural importance, requiring a name. Cultivars propagation results in little to no genetic change in the offspring, preserving desirable characteristics

Cultivation - working of the soil without the destruction of the turf

Cultural insect control - controlling an insect population by maintaining good plant health and by crop rotation and/or companion crops

Cuneate - wedge-shaped, tapering at an acute angle toward the base

Curlytop - rolling and curling of leaves at the growing point. May indicate a viral infection

Cuticle - waxy layer on the epidermis on leaves or fruit that which protects the tissue against excess moisture loss; outer layer of an insect’s body

Cutin - waxy substance on plant surfaces that tends to make the surface waterproof and can protect leaves from dehydration and disease; waxy substance on an insect’s cuticle that protects the insect from dehydration

Cuttings - detached vegetative plant parts which when placed under conditions favorable for regeneration and develop into a complete plant with characteristics identical to the parent plant. It is one of several forms of asexual propagation

Cyme - broad, more-or-less flat-topped determinate (having a fixed number) flower stalk on which the florets start blooming from the top of the stem and progress toward the bottom

Cyst - swollen, egg-containing female body of certain nematodes. Can sometimes be seen on the outside of infected roots

Cytokinins - class of plant growth substances (phytohormones) that promote cell division, or cytokinesis, in plant roots and shoots, and promote the growth of buds

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