Displaying 1501 - 1575 out of 1575 Object(s)

Per Page

• 25
• 50
• 75

Term	Definition
Type	"A nomenclatural type (typus) is that element to which the name of a taxon is permanently attached, whether as the correct name or as a synonym. The nomenclatural type is not neccessarily the most typical or or representative element of a taxon." This quotation is from The International Code of Botanical Nomenclature (Vienna Code) 2006. The ICBN is updated every five years based on recommendations sent to the ICBN Committe and discussed at the International Botanical Congress which meets at different places in the world. The latest ICBN is available online (http://ibot.sav.sk/icbn/main.htm) and as hardcopy.
Type specimen	A specimen chosen to represent a species and is cited as such in the publication in which the species is described. There are different types of types, e.g. see holotype, isotype, syntype. The International Code of Botanical Nomenclature now requires that one specimen be designated as the holoytpe.
Umbel	A convex- or flat-topped inflorescence with all pedicels arising from the same point.
Umbela	Una inflorescencia distalmente convexa, cuyos pedicelos salen de un mismo punto de inserción. Las umbelas compuestas son típicas de las Apiaceae y algunas especies de Araliaceae y Smilacaceae
Umbell	A convex- or flat-topped inflorescence with all pedicels arising from the same point.
Umbo	A relatively small protrusion usually in the middle of a structure; e.g., the operculum of a fruit.
Umbonate	Referring to a structure, such as a fruit apex, that possesses an umbo.
Unbranched inflorescence	An inflorescence with a single rachis.
Uncinate	Hooked at the apex.
Uncinate	Hooked at the apex, usually refers to stiff trichomes that stick in the fur or clothing of animals to facilitate seed dispersal.
Understory tree	A tree growing in a hypothetical stratum in the forest consisting of the crowns of trees found below the canopy and usually less than 20–25 meters tall at maturity.
Understory tree	A species of tree in which adult individuals do not reach the more-or-less continuous canopy tree layer of a forest.
Undulation (adj. = undulate)	Wavy, usually referring to the margin of a structure such as a leaf.
Unguiculate	Referring to a structure, such as a petal, the is abuptly constricted toward the base (having a claw). Same as clawed.
Uni-	A prefix meaning one.
Unicate collection	Referring to a collection number that is represented by a single herbarium specimen. Unicate collections are made when additional collections are not available, when a plant is rare and permission has been obtained to make a collection that does not adversely impact the population from which it is collected, or when a species is so well known that the only reason for collecting it is to document its presence in a specific locality. For more information about plant collecting see Tropical Plant Collecting: From the Field to the Internet. This book can be purchased at: http://tecceditora.com/ or Amazon.com.
Unilaterally winged seed	Referring to a seed wing that arise from one side.
Uniseriate perianth	Referring to a perianth with a single whorl composed of either the calyx or the corolla; e.g., the perianth of Nyctaginaceae and Thymelaeaceae.
Unisexual flower	Referring to a flower with either functional stamens or functional gynoecia but not both. Same as imperfect flower.
Unitegmic ovule	An ovule with one integument.
Upper septum	In neotropical Lecythidaceae, the part of a wall-like partition of a locule located above an articulation (often only seen as a thin line), as seen in longitudinal section, that divides the septum into a lower part and an upper part.
Urceolate	Shaped like an urn, same as urn-shaped.
Urn-shaped	Shaped like a vase that is wide at the base and narrower at the apex. Same as urceolate.
Urticating trichomes	Trichomes that cause itching or burning sensations such as in some species of Euphorbiaceae and Urticaceae; sometimes called urticating hairs but urticating trichomes is preferred because it limits the term to plants. Urticating trichomes are thought to protect the plant from predators.
Valva	Cada uno de los segmentos de un fruto dehiscente que hipotéticamente representa a un carpelo del ovario
Valvate (adjj.)	A type of aestivation in which the edges of the sepals and petals meet exactly and do not overlap (compare with imbricate); referring to the opening of an anther by small flaps; e.g., in Lauraceae.
Valve	One of the segments of an ovary each of which is hypothesized to represent a carpel or one of the segments of a dehiscent fruit.
Variegated leaves	Having streaks, marks, or patches of different colors; e.g., the immature leaves of some species of Calathea (Marantaceae) and several species of Psychotria (Rubiaceae), and the mature leaves of Cyclopogon olivaceus (Orchidaceae).
Várzea	A Portuguese term referring to forest growing in areas periodically indundated by alkaline, café au lait-colored water (also called white water).
Várzea	A Portuguese term referring to forest growing in areas periodically indundated by alkaline, café au lait-colored water (also called white water). Do not confuse white-water with rapidly flowing water of rapids and waterfalls. See Prance (1979) for more information about forests subjected to inundation in Amazonia.
Vascular bundle	In the angiosperms, separate strands of phloem and xylem cells that transport water and nutrients to the leaves and photosynthate (carbohydrates produced by photosynthesis) to other parts of the plant.
Vascular trace	That part of a vascular bundle extending from the vascular cylinder of the stem into the base of the leaf.
Vegetative reproduction	Referring to non-sexual reproduction, by ramets developing from stolons, sprouts from rhizomes, budding from the leaves, tubers, or bulblets.
Venule	The ultimate division of the venation of a leaf blade.
Versatile anther	A stamen in which the filament is attached to the anther above the base of the anther.
Verticilada	Se refiere cuando tres o más órganos se encuentran dispuestos en el mismo plano e insertos en un mismo nudo alrededor de un tallo; por ejemplo, a las hojas en un tallo. Comparar con alterna y opuesta
Verticillate	Arising from an axis in groups of more than two at the same node; e.g., leaves along a stem or flowers along a rachis. Same as whorled. Compare with alternate and opposite.
Very narrowly elliptic	Referring to a two-dimensional shape with the widest point at the middle and tlength to width ratio of 6:1 or more.
Very widely oblong	Referring to a two dimensional shape in which the greatest width extends throughout a middle zone at least one-third the length of the blade (in this zone the margins are more-or-less parallel) and the length to width ratio is 1.2:1 or less.
Very widely obovate	Very widely obovate refers to a leaf, sepal, petal, or other flat structure that is wider above the midpoint and has a length-to-width ratio of 1:1 or less.
Very widely ovate	Very widely ovate refers to a leaf, sepal, petal, or other flat structure that is wider at the base than at the midpoint, tapers toward the apex, and has a length-to-width ratio of 1:1 or less.
Vestigial stamen	An appendage derived directly from a staminode and indirectly from a stamen that no longer has an anther or the anther is small and withered compared to the fertile anthers of normal stamens in the staminal ring or the fodder pollen-producing anthers of staminodes.
Vestigial stamen nectaries	In the Lecythidaceae, the inner-most appendages at the apex of a fully-coiled, zygomorphic-flowered, neotropical Lecythidaceae that produce nectar which accumulates in the nectar chamber. Nectar-producing vestigial stamens and nectar chambers are only found in species of Couratari and Eschweilera sensu lato. Fully coiled refers to species that have more than one inward coil, i.e., species with two or more coils.
Vestigial stamens	An appendage, most likely derived directly from a staminode and indirectly from a stamen, that no longer has an anther or the anther is small and withered compared to the fertile anthers of normal stamens in the staminal ring or the fodder pollen-producing antherodes of staminodes.
Vestigial stamens external	Referring to an inwardly, once coiled androecial hood that possesses vestigial stamens only on the outside (externally of the coil. This feature is only used to describe species with at single coil.
Vestigial stamens internal	Referring to an inwardly, once-coiled androecial hood that possesses vestigial stamens on the inside (internally) as well as on the outside of the coil (externally).
Vexillum	The upper, broad petal of Fabaceae. Same as standard, flag, and banner with standard the preferred term.
Viscidium	In the Orchidaceae, a sticky part of the rostellum that is removed with the pollinia as a unit and serves to attach the pollinia to the dispersal agent.
Vivipary (viviparous)	In plants, germinating while still attached to the parent plant.
Voucher	A herbarium specimen used to document the identification of a species of plant in floristic, monographic, anatomical, ecological, economic, medicinal, taxonomic, etc. studies. If a voucher does not document plant studies there is no way to confirm or reject the identifications of the species in the studies.
Water dispersal	Referring to diaspores that are carried away from the mother plant by water. Most water dispersed seed have corky seed coats. However, other species have seeds with arched cotyledons that surround air spaces that give the seeds bouyancy and others have entire fruits that fall into the water.
Weed	A plant that grows anywhere that a human does not want it to grow. Most of the time invasive plants are considered to be weeds.
Whorled	Arising from an axis in groups of more than two at the same node; e.g., leaves from a stem or flowers from the rachis of an inflorescence. Same as verticillate. Compare with alternate and opposite.
Whorled leaves	Arising from an axis in groups of more than two leaves at the same node; e.g., leaves along a stem or flowers along a rachis. Same as verticillate. Compare with alternate and opposite.
Widely elliptic	A widely elliptic shape is widest at the middle and possesses a length to width ratio greater than 1.5:1 to less than 2:1. Based on Hickey (1973).
Widely oblong	Referring to a two dimensional shape in which the greatest width extends throughout a middle zone at least one-third the length of the blade (in this zone the margins are more-or-less parallel) and the length to width ratio is 1.5:1 to less than 2:1.
Widely obovate	Widely obovate refers to a leaf, sepal, petal, or other flat structure that is wider above the midpoint and has a length-to-width ratio of 1.2:1 to less than 2:1.
Widely ovate	Widely ovate refers to a leaf, sepal, petal, or other flat structure that is wider at the base than at the midpoint, tapers toward the apex, and has a length-to-width ratio of 1.2:1 to less than 1.5:1.
Wind dispersal	Referring to a type of seed dispersal in which the diaspores are carried away from the mother plant by the wind. The most common types of wind-dispersed plants are those with winged fruits and seeds and comose seeds. Same as anemochory.
Wind pollination	Pollination by the wind, i.e., the movement of pollen by the from the stamens of a flower to the stigma of another flower. This includes movement for the anther to the stigma of the same flower, from the anther to the stigma of another flower on the same plant, or from the anther of a flower on one plant to the stigma of a flower on another plant. Same as anemophily.
Wing	Either of the two lateral petals of a flower of Fabaceae; a thin, flattened outgrowth from stems, petioles, fruits, or seeds,in the latter definition a winged organ is the same as an alate organ.
Winged	With a thin, conspicuous ridge running down the length of a structure such as a stem, leaf rachis, ovary, or fruit. Same as alate.
Winged fruit	Referring to fruits that either have have wings along their length that do not aid in wind dispersal or to fruits that have well-developed wings that aid in wind dispersal. Note that both winged fruits and winged seeds aid in wind dispersal.
Winged seed	Referring to seeds with a wing-like extensions that surround the seed, are are two sides of the side, or extend from one end of the seed, all of which facilitate wind dispersal.
Wood cross section	An anatomical section that runs at right angles to the main axis of the stem or the trunk.
Wood radial section	A wood anatomical section that runs parallel to the rays.
Wood tangential section	A wood anatomical section that cuts across the rays of a block of wood or a stem.
Xenogamy (Xenogamous)	Referring to the fertilization of the ovules of a flower by pollen from a flower on a different plant. Compare with geitonogamous.
Xeric	Referring to dry habitats.
Xylem	The water-and mineral conducting tissue of plants, which (with age) loses this function and serves to support the plant,
Xylopodium (plural = xylopodia)	An underground, woody, storage organ derived from stems or roots and common in cerrado vegetation.
Zarcillo	Filamento espiral, propio de las plantas trepadoras, que ayuda a trepar; por ejemplo, en Bignoniaceae, Passifloraceae y Vitaceae
Zigomorfa	Cuando una estructura solamente puede ser dividida en dos partes iguales. Este término usualmente es aplicado a las flores. Zigomorfa es lo mismo que irregular y radialmente asimétrica (simetría radial). Es opuesto a actinomorfa.
Zygomorphic	Capable of being divided into only two equal parts; a structure in which a line drawn through the middle will produce a mirror image of one side of the line to the other side of the line.
Zygomorphic flower	A flower capable of being divided into only two equal parts (mirror images) by a line passing through the middle of a flower, i.e., other lines passing the middle of the flower will not give mirror images of one another; same as monosymmetric, bilaterally symmetrical, and irregular flowers and opposite of actinomorphic, monosymmetric, radially symmetrical, and regular flowers. This term can refer to other plant parts as well.

• First
• Previous
• Page / 21