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Twig
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A small branch of a tree to which the leaves are attached, i.e., the ultimate, leaf-bearing branch. |
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Twig
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A branch of a tree of Lecythidaceae to which the leaves are attached, i.e., the ultimate, leaf-bearing branch. |
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Two-ranked
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Referring to structures that are arranged in two rows; usually referring to the way in which leaves or bracts are inserted on an axis. Same as distichous. |
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Type
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"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. |
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Type specimen
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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. |
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Umbel
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A convex- or flat-topped inflorescence with all pedicels arising from the same point. |
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Umbela
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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 |
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Umbell
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A convex- or flat-topped inflorescence with all pedicels arising from the same point. |
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Umbellate
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Like an umbel. |
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Umbo
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A relatively small protrusion usually in the middle of a structure; e.g., the operculum of a fruit. |
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Umbonate
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Referring to a structure, such as a fruit apex, that possesses an umbo. |
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Uña
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Es la parte baja, delgada y alargada de un pétalo libre. Por ejemplo, en las Malpighiaceae, algunas leguminosas y Lagerstroemia speciosa de Lythraceae. Ver unguiculado. |
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Unbranched inflorescence
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An inflorescence with a single rachis. |
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Uncinate
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Hooked at the apex. |
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Uncinate
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Hooked at the apex, usually refers to stiff trichomes that stick in the fur or clothing of animals to facilitate seed dispersal. |
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Understory Score
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0-25 scale of the % understory complement present compared to an "ideal" state, and % of that understory modified or disturbed in some way |
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Understory tree
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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. |
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Understory tree
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A species of tree in which adult individuals do not reach the more-or-less continuous canopy tree layer of a forest. |
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Undulate
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Wavy, usually referring to the margin of a structure such as a leaf. |
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Undulation (adj. = undulate)
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Wavy, usually referring to the margin of a structure such as a leaf. |
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Unguiculada, unguiculado
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Se refiere va aquellos pétalos libres que están abruptamente adelgazados y algo alargados hacia la base, es decir, provistos de una uña. Lo mismo que uñado. |
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Unguiculate
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Referring to a structure, such as a petal, the is abuptly constricted toward the base (having a claw). Same as clawed. |
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Uni-
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A prefix meaning one. |
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Unicate collection
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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. |
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Unifacial
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Referring to a leaf with the same type of tissue on each side as observed in a transverse section. |
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Unifoliate
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Referring to a plant with one leaf. |
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Unifoliolate leaf
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A leaf appearing to be simple but believed to be derived from an ancestor with a compound leaf, commonly found in species of Fabaceae. |
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Unilaterally winged seed
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Referring to a seed wing that arise from one side. |
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Unilocular
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Referring to an ovary with a single locule. |
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Uniseriado
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Se aplica a un perianto que posee un sólo verticilo, ya sea que esté conformado por el cáliz o por la corola; e.g., el perianto de Nyctaginaceae y Thymelaeaceae. Este término también se aplica a pelos pluricelulares, cuyas células están dispuestas en una sola hilera, en sentido longitudinal. |
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Uniseriate perianth
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Referring to a perianth with a single whorl composed of either the calyx or the corolla; e.g., the perianth of Nyctaginaceae and Thymelaeaceae. |
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Unisexual flower
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Referring to a flower with either functional stamens or functional gynoecia but not both. Same as imperfect flower. |
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Unitegmic ovule
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An ovule with one integument. |
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Upper
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See adaxial. |
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Upper septum
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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. |
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Urceolate
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Shaped like an urn, same as urn-shaped. |
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Urn-shaped
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Shaped like a vase that is wide at the base and narrower at the apex. Same as urceolate. |
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Urticaceous stamens
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Stamens that spring forward to release pollen at anthesis; typical of the flowers of the Urticaceae and some related families. |
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Urticant
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Causing itching or stinging when touched. |
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Urticating trichomes
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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. |
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Utricle
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A small, one-seeded, somewhat inflated, usually indehiscent fruit; e.g., in some species of Caryophyllaceae, Lemnaceae, and Plumbaginaceae; the inflated basal chamber formed by the perianth of Aristolochia (Aristolochiaceae); in Cyperaceae, see perigynium. |
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Utriculate
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In the shape of a bladder. |
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UV pattern
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Markings on a flower that are only seen under ultra-violet light by humans or to insects without being exposed to UV light. These markings usually serve as honey guides to the insects. |
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Vacuole
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A space or cavity within the cell. |
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Vaginate
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Possessing a sheath; e.g., used to describe the petiole base of some species of Piper. |
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Valva
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Cada uno de los segmentos de un fruto dehiscente que hipotéticamente representa a un carpelo del ovario |
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Valvate (adjj.)
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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. |
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Valve
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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. |
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Variegated leaves
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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). |
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Variety (abbreviation = var.)
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A subdivision of subspecies, i.e., a rank between and subspecies and a form. |
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