acidophobia an inability to accommodate to acid soils. Cf. basophobia. —acidophobic, adj. amensalism a parasitic relationship between plants that has a destructive effect on one and no effect on the other. apheliotropism the tendency of some plants to grow in a direction away from the sun. apogeotropism the tendency of some plants to grow away from the earth and the pull of gravity. —apogeotropic, adj. aquapontics the cultivation of plants in nutrient solutions, usually for commercial purposes. Cf. hydroponics. —aquapontic, adj. aquiculture hydroponics. —aquicultural, adj. auxography the measurement of the swelling and shrinking of parts of plants. —auxographic, adj. basiphobia an inability to accommodate to alkaline soils. Cf. acidophobia. —basophobic, basiphobic, adj. biodynamics the study of the physiological processes of plants and animals. —biodynamic, biodynamical, adj. biostatics the study of the relation between structure and function in plants and animals. —biostatical, adj. biota the animal or plant life of a particular region. botanomancy a form of divination involving the examination of plants. caricography the description of plants belonging to the genus Carex. caricology the study of sedges. —caricologist, n. cecidiology, cecidology Biology. the study of galls produced on trees and plants by fungi, insects, or mites. —cecidiologist, cecidologist, n. chlorosis 1. a diseased condition of plants in which green parts lose their color or turn yellowish. 2. the process by which floral parts of a plant turn into leaves. Also chloranthy. See also disease and illness. citriculture the cultivation of citrus fruits, as lemons, oranges, etc. —citriculturist, n. crescography a technique for making apparent to the eye the successive stages of plant growth. —crescographic, adj. cumaphytism the procedures involved in adapting plants for growth under surf conditions. —cumaphytic, adj. dendrophilia the apparent preference of some plants, as orchids, to grow in or near trees. —dendrophilous, adj. desmidiology the study of microscopic single-celled algae. —desmidiologist, n. diatropism the capacity or tendency of some plants to adopt a position transverse to the line of force of an external stimulus. —diatropic, adj. dichogamy the condition, in some flowering plants, in which the pistils and stamens mature at different times, thus preventing self-pollination. —dichogamous, adj. ecesis the transplanting of a plant to a new environment. epiphytism a form of mutualism in which one plant lives on the surface of another, as moss on a tree. —epiphyte, n. etiolation 1. the process of growing plants away from the light to make them white and crisp, especially in vegetable gardening. 2. the condition of the plants grown in this manner. See also disease and illness. exostosis a knot growing on the stem or root of a plant. See also bones. florimania a mania for plants and flowers. fungicide a substance that kills fungi or retards the growth of spores. halophytism the ability of certain plants to grow normally in solis having a high mineral salt content. —halophyte, n. —halophytic, adj. heliophilia an attraction or adaptation to sunlight, as the sunflower. —heliophile, n. —heliophilic, heliophilous, adj. heliotaxis a tendency of certain plants to move in response to sunlight. heliotropism the tendency in some plant species to turn or grow toward sunlight. —heliotrope, n. —heliotropic, adj. herbalist a person who collects or deals in herbs, especially for medicinal purposes. See also botany. herbarist Obsolete, a herbalist. herbicide a substance for destroying plants, especially weeds or other unwanted species; a weed-killer. —herbicidal, adj. heterosis abnormal development, especially increased size, in plants or animals, usually as a result of cross-breeding. hydrophily ombrophily. hydrophytism the ability of certain plants to grow naturally in water or in highly moist soils. —hydrophyte, n. —hydrophytic, adj. hydroponics the science of growing plants in specially prepared solutions instead of in soil. Cf. aquapontics. —hydroponic, adj. hypertrophy excessive growth of one part of a plant to the disadvantage or detriment of the plant as a whole. See also body, human; size. —hypertrophic, hypertrophical, hypertrophous, adj. hyponasty an increase in growth in a lower part of a plant causing it to bend upward. —hyponastic, adj. mangonism Obsolete, any procedure for raising plants under other than natural conditions of growth. mesophytism the ability of certain plants to grow naturally in moderate but constant moisture. —mesophyte, n. —mesophytic, adj. mycolatry the worship of fungi, especially mushrooms. olericulture the branch of horticulture that specializes in the cultivation of edible plants. —olericultural, adj. ombrophily the capacity of some plants to thrive in the midst of copious rain. Also called hydrophily. —ombrophilic, ombrophilous, adj. parasitism a relationship between plants in which one gains sustenance from the other. See also animals; biology. perigyny the state of having the pistils, stamens, petals, etc., arranged around a cuplike receptacle. —perigynous, adj. pesticide any chemical substance used for killing pests, as insects, weeds, etc. philobotanist Rare. a lover of plants. photodynamics the science or study of light in relation to the movement of plants. —photodynamic, photodynamical, adj. photonasty the tendency in certain plant species to respond to light by developing sufficient cellular force or growth on one side of an axis to change the form or position of the axis, as in the opening and closing of the flowers of four-o’clocks. Cf. thermonasty. —photonastic. adj. photoperiodism the study of the relative amounts of light and darkness in a 24-hour period required to best effect the growth, reproduction, and flowering of plant species or the growth and reproduction of animals. Also photoperiodicity. Cf. thermoperiodism. —photoperiodic, photoperiodical, adj. photophily the necessity, in some plant species, for exposure to strong light. —photophile, photophilic, photophilous, adj. photosynthesis the synthesis of complex organic substances from carbon dioxide, water, and inorganic salts, with sunlight as the energy source and a catalyst such as chlorophyll. —photosynthetic, adj. phototropism motion in response to light, either toward it or away from it, as manifested by certain plants. —phototropic, adj. phytogenesis, phytogeny the origin and evolution of plants. —phytogenetic, phytogenetical, phytogenic, adj. phytoserology the identification, classification, and study of plant viruses. —phytoserologist, n. —phytoserologic, phytoserological, adj. plagiotropism the tendency of some plants to diverge from the vertical in their growth. —plagiotropic, adj. rheotropism the tendency of some plants to respond to a current of water by growing with it (positive rheotaxis) or against it (negative rheotaxis). saprophytism the ability of certain plants to live in dead or decaying organic matter. —saprophyte, n. —saprophytic, n., adj. sclerosis the hardening of the cell wall of a plant, as by the formation of wood. See also body, human. —sclerotic, adj. stirpiculture selective breeding to develop strains with particular characteristics. —stirpicultural, adj. sycomancy the art of divination by inspection of figs or flg leaves. thermonasty the tendency in certain plant species to respond to temperature changes by developing a sufficient cellular force or growth on one side of an axis to change the form or position of the axis, as in the closing or folding of rhododendron leaves in cold air. Cf. photonasty. —thermonastic, adj. thermoperiodism the study of the relative day and night temperatures required, in a 24-hour period, to achieve the best growth, reproduction, or flowering of plant species or the growth and reproduction of animals. Also thermoperiodicity. Cf. photoperiodism. —thermoperiodic, thermoperiodical, adj. thermotropism the tendency in some plant species to turn toward or away from a source of heat. —thermotropic, thermotropical, adj. xenogamy cross-fertilization in plants or flowers. xerophily the ability of some plants to survive in dosert or salt marsh areas by storing fresh water internally. —xerophilic, xerophilous, adj. xerophytism the natural adaptation of plants living under desert or marsh conditions to store water internally. —xerophyte, n. —xerophytic, adj.