acaulescent - a. (Gr. a, without; kaulos, stalk) having no stem or seemingly without a stem. accessory flower parts - sepal and petal organs found on flowers. The sepals and petals are not essential for pollination but may aid in attracting insects or other organisms. achene - n. (Gr. a, not; chainein, to gape) any small, dry fruit with one seed whose outer covering (pericarp) does not burst when ripe. acicular - a. (L. acicula, a small needle) slender and pointed; needle-like and with a sharp point. acropetal - a. (Gr. akros, summit; L. petere, to seek) developing upward from the base toward the apex. actinomorphic - a. (Gr. aktis, ray; morphe, form) descriptive of a flower or set of flower parts which can be cut through the center into equal and similar parts along two or more planes; having radial symmetry. aculeus - n. (L. aculeus, prickle) a prickle growing from bark. pl. aculei. acumen - n. (L. acumen, a point, a sting) the point of an acuminate leaf. acuminate - a. drawn out into a long point; tapering point. acute - a. (L. acutus, sharpened) sharp at the end; ending in a sharp point. adaxial - a. (L. ad, to; axis, axle) pertaining to the side of an organ toward the axis, such as the upper surface of a leaf. adnate - a. (L. adnatus, to be born, to grow to) fusion of unlike structures or parts. adventitious - a. (L. adventitius, extraneous) plant structures or tissue occurring in an abnormal positon. adventive - a. (L. advenire, to arrive) a plant that is not native to the environment. aerenchyma - n. (Gr. aer, air; enchyma, an infusion) parenchyma tissue with large and abundant intercellular air spaces; air-storing tissue; resembles the tissue of cork. aggregate - a. (L. ad, to; gregare, to collect into a flock) crowded into a cluster; a number of separate fruits from a single flower aggregated together; an aggregate flower is formed by a cluster of carples. allele - n. (Gr. allelon, one another) one of a pair or more of alternative hereditary characters; a gene which can occupy the same locus as another gene in a particular chromosome. allelochemicals - compounds that have an allelopathic effect. allelopathy - n. (Gr. allelon, one another; pathos, suffering) the influence or effect of one living plant upon another; refers to biochemical interaction between all types of plants and its effect depends on a chemical compound being added to the environment. alternate - a. (L. alteratus, one after another) said of leaves occurring one at a node; said also of members of adjacent whorls in the flower when any member of one whorl is in front of or behind the junction of two adjacent members of the succeeding whorl. alternation of generations - the occurrence in one life history of two or more different forms differently produced, usually an alternation of a sexual with an asexual form. alveola - n. (L. alveolus, small cavity) a pit on the surface of an organ. alveolate - a. (L. alveolatus, pitted) deeply pitted so as to resemble a honeycomb, as are the surfaces of some seeds or achenes. anaerobiosis - n. (L. Gr. an, without; aer, air; biosis, manner of life) life in the absence of air or free oxygen; anaerobic respiration, respiration occurring in the absence of oxygen. anastomosis - n. (Gr. ana, up to; stoma, mouth) connecting by cross-veins and forming a network. anatomy - n. (LL. anatomia, dissection) the branch of morphology that deals with the structure of plants, esp. the internal structure as revealed by the microscope. androecium - n. (Gr. andros, man; oikos, house) male reproductive organs of a plant; a collective term applied to all structures of the stamen whorl or whorls. androgynal - a. (Gr. andros, man; gonos, woman) bearing staminate and pistillate flowers on the same parent stem. androgynous - staminate flowers above the pistillate flowers in the same inflorescence. androphore - n. (Gr. aner, man; phoros, carrying) a support or column, formed by fusion of filaments, on which the stamens are borne. anemophily - n. (Gr. anemos, wind; philein, to love) pollination by wind. Angiospermae - n. (Gr. anggeion, vessel; sperma, seed) a major division of the plant kingdom, commonly called flowering plants as their reproductive organs are in flowers, having seeds which develop in a closed ovary made of carpels, a very reduced gametophyte, and endosperm develop from a triple fusion nucleus. pl. Angiosperms. annual - a. (L. annualis, yearly, from annus, year) a plant which completes its life history within a year. anoxia - n. (L. an, not; and oxygen) lack of oxygen or not enough oxygen. anther - n. (Gr. antheros, flowery, from anthein, to bloom) the top of the stamen, usually elevated by means of a filament, which contains the pollen. anthesis - n. (Gr. anthesis, bloom, from anthein, to bloom) stage or period during which the flower bud is fully open; flowering. antrorse - a. (L. ante, before; vertere, to turn) forward or upward. apetalous - a. (Gr. a, without; petalon, leaf) having flowers without petals; having no corolla. apical - a. (L. apex, the tip or top of a thing) at the tip or summit. apiculate - a. (LL. apiculatus, point) terminated abruptly by a small, distinct point, an apiculus or apicule. apocarpous - a. (Gr. apo, away; karpos, fruit) having separate carpels. apomixis - n. (Gr. apo, away; mixis, a mixing) in general, reproducing without sexual reproduction; often used to denote seed production without a sexual process having been involved. appressed - a., adv. (L. ad, to; pressare, to press) lying flat or close against something. Often used for hairs. aquatic plants - plants that must grow in water whether rooted in the mud or floating without anchorage; plants that must complete part or all of their life cycle in or near the water. aquatic vascular plants - aquatic plants containing the conductive vascular tissue, phloem and xylem. arachnoid - a. (Gr. arachme, spider, cobweb; eidos) like a cobweb; covered with or consisting of soft fibers or hairs so entangled as to give a cobwebby appearance. arcuate - a. (L. arcuatus, pp. of arcuare, to arch, bend like a bow, from arcus, a bow) bent or curved in the form of a bow. aril - n. (Fr. arrile, Sp. arillo, L. arilli, dried grapes, from aridus, dry) an additional covering that forms on some seeds after fertilization, and developing from the stalk of the ovule. aristate - a. (L. arista, awn) awned; having an awn. articulate - a. (L. articulatus, jointed, pp. of articulare, to join) having joints; jointed; provided with places where separation may take place. ascending - v. (Fr. scandere, to climb) rising or curving upward. asepalous - a. (Gr. a, without; L. pelatum, petal) without sepals. attenuate - a. (L. attenuare, to thin) gradually narrowed to a long point at apex or base. auricle - n. (L. auricle, small ear) any ear-like lobed appendages. aut- or auto- - comb. form. (Gr. from autos) a combining form meaning self.
autogamous - adj., relating to, or
reproducing by autogamy. autogamy - n. (aut- + -gamy, Gr. -gamia, fr, gamos, marriage) self-fertilization, pollination of a flower by its own pollen. auxins - growth promoting hormones that cause cell elongation, and are responsible for many developmental responses including phototropism. awn - n. (Icel. ogen, chaff) a stiff, bristlelike appendage, usually at the end of a structure. axil - n. (L. axilla, armpit) the angle found between any two organs or structures. axillary - a. (L. axilla, armpit) in an axil, growing in an axil, as buds. |