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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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