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Tap: [Roots] {type} An enlarged vertical main root that is noticeably larger in diameter than any attached lateral roots.

Tendril-bearing : [2-4-year-old twigs, Petioles, Rachises] {special surface features} With a slender, twining organ used to grasp support for climbing, as grape (Vitis) vines.

Tepal: any of the modified leaves making up a perianth

Terete: approximately cylindrical but usu. tapering at one or both ends

Terminal: (1) At the top, tip, or end of a structure.

Terminal: (2) [Inflorescences, Seed cones] {position} At the apex or tip of the stem.

Terminal (3) : [Buds] {position} At the apex or tip of the stem.

Ternate: In threes, as a leaf which is divided into three leaflets.

Tessellated [Leaf lower surface, Leaf upper surface] {color variegation} Color arranged in small squares, so as to have some resemblance to a checkered pavement.

Thorn: A woody, sharp-pointed, modified stem.

Three-angled: [Leaf cross section] {shape} More or less triangular-shaped in cross section.

Three-ranked: [Leaves] {habit} With leaves arranged in along the stem in three rows.

Thyrse: [Inflorescences] {type} An elongate, many-flowered inflorescence with an indeterminate main axis or rachis and numerous lateral branches, each in the form of a cyme, as in most lilacs (Syringa).

Thyrsoid: having somewhat the form of a thyrse

Tomentose: [Buds, Leaf lower surface, Leaf upper surface, Petioles, Phyllaries, Sepals, Young twigs] {pubescence type} With tangled woolly hairs.

Tracheid: a long tubular cell that is peculiar to xylem, functions in conduction and support, and is characterized by tapering closed ends which are not absorbed as in tracheae and by thickened strongly lignified walls which commonly have bordered pits

Tree: [Plants] {habit} A relatively tall, woody, perennial plant usually with a single stem (trunk) that bears branches.

Trichome: Any type of plant hair (except for root hairs).

Trifoliolate: [Leaves] {complexity form} Compound with three leaflets; three-leafleted or ternate.

Tripalmately compound: [Leaves] {complexity form} With three orders of leaflets, each palmately compound; three-times palmately compound.

Tripinnately compound: [Leaves] {complexity form} With three orders of leaflets, each pinnately compound; three-times pinnately compound.

Tripinnately lobed: [Leaves] {lobing form} With three orders of leaf lobing, each pinnately lobed; three-times pinnately lobed.

Tripinnate-pinnatifid: [Leaves] {complexity form} Three times pinnately compound with pinnatifid leaflets.

Triternate: [Leaves] {complexity form} With three orders of leaflets, each divided into threes or ternately compound; three-times trifoliolate.

Truncate: (1) [Leaf apices, Leaflet apices, Petal apices, Phyllary apices, Sepal apices] {shape} With the apex cut more or less straight across; ending abruptly, almost at right angles to the midrib.

Truncate: (2) [Leaf bases, Leaflet bases] {shape} With the base cut more or less straight across; ending abruptly, almost at right angles to the midrib.

Trunk: The aboveground, relatively stout, main stem of a tree; the bole.

Tuber: [Stems] {type} A solid, enlarged, horizontal, shortened stem, usually borne below ground and containing food reserves, as in potatoes (Solanum tuberosum).

Tubercle: This is a small bump or wart-like structure on the surface of a floral structure. This typically refers to the surface of an achene (seed), which may have a single tubercle, or its surface may be more or less covered with a multitude of minute tubercles. Sometimes 'tubercle' refers to the spore-bearing structures on horsetails and ferns, which often have a bumpy appearance.

Tuberculate: The granular-pebbly surface of a seed.

Tuberous: A tuberous root system consists of a loose collection of coarse roots that occasionally thicken into fleshy underground tubers. These tubers store water and energy for the plant. Occasionally, rhizomes develop from the tubers that can produce new plantlets.

Tussock: The dense mat of roots at the base of some plants push the ground upward to form a mound, which is called a 'tussock.' Such plants often have multiple stems that develop directly from the tussock; this includes some species of grass, sedge, and fern

Twig: The relatively small end portion of a woody branchlet; a small branchlet.

Two-angled: [Leaf cross section] {shape} More or less flat in cross section, with an upper and lower surface.

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Umbel: a racemose inflorescence that is characteristic esp. of the family Umbelliferae and has the flower stalks in a cluster arising from a common point at the apex of the main stalk and reaching approximately the same height and sometimes branching again to form secondary clusters

Umbellate: bearing, consisting of, or arranged in umbels   2 : resembling an umbel in form

Unarmed: [Seed cone scales] {armature} Without a hook, prickle or other sharply pointed structure on the end of the cone scale.

Undulate: [Leaf margins, Leaflet margins] {vertical disposition}; [Petal margins, Phyllary margins, Sepal margins] {form} With the margin undulating or wavy in a vertical plane.

Unifoliolate: [Leaves] {complexity form} A structurally compound leaf with a single leaflet, making it appear simple, the compound nature of the leaf evident by a distinct articulation in the leaf stalk, as in redbud (Cercis canadensis); one-leafleted.

Unilocular: With a single interior compartment or locule.

Unisexual: [Flowers] {gender} Having functional reproductive structures of only one sex in the flower or cone.

Unlobed: [Leaflets, Leaves, Petals, Sepals] {lobing} With no recesses or indentations in the margin, or with indentations extending less than  the distance to the midrib or base.

Utricle: [Fruits] {type} A more or less small, dry fruit that does not split open at maturity (indehiscent), with a thin bladder-like outer wall that is loose and free from the single seed.

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Valvate: [Bud scales] {type} With scales (usually two) meeting by the edges without overlapping.

Valve: Some seed capsules are divided into cells with rounded exterior walls. The protruding walls of these cells are often referred to as "valves." Thus, a 3-celled seed capsule with 3 protruding walls is "3-valved." This also refers to the shape of the ovulum (base of the pistil) when such cells are present.

Variably serotinous: [Seed cones] {serotiny} Having some cones that open when the seeds ripen and others that remain closed long after the seeds are ripe.

Variegated [Leaf lower surface, Leaf upper surface] {color variegation} The color disposed in various irregular, sinuous, spaces.

Vascular bundle: A strand of conducting tissues and associated cells within a stem or connected structure.

Vegetative: 1) Of, or relating to, the non-flowering parts of a plant. 2) Producing new plants asexually by the spread or fragmentation of sterile (non-reproductive) tissue, without the formation of seeds.

Velamen (pl. velamina) : the thick whitish or greenish multiseriate corky epidermis covering the aerial roots of an epiphytic orchid and consisting of compactly arranged nonliving cells capapble of absorbing water from the atmosphere

Vernation: the arrangement of foliage leaves within the bud

Verticil: a circle or whorl of similar body parts (as flowers about a point on an axis . . . )

Verticillaster: [Inflorescences] {type} A pair of axillary cymes arising from opposite leaves or bracts and forming a false whorl, as in many salvias (Salvia).

Vessel: a conducting tube in a vacscular plant formed in the xylem by the fusion and loss of end walls of a series of cells -- compare TRACHEID

Vestigial: relating to or being a vestige, [being] a small and degenerate or imperfectly developed bodily part or organ that remains from one more fully developed in an earlier stage of the individual, in a past generation, or in closely related forms

Villous: [Buds, Leaf lower surface, Leaf upper surface, Phyllaries, Sepals, Young twigs] {pubescence type} With slender curved or wavy, but not matted hairs.

Vine: [Plants] {habit} A perennial plant with long woody or herbaceous stems that are flexible (at least initially), and are supported by other plants or structures, or that trail across the ground.

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Warty: [Bark of mature trunks] {surface appearance} Bark with relatively small, scattered protuberances, as in southern hackberry (Celtis laevigata).

Weak: [Seed cone armature] {strength} With armature that tends to break easily.

Weed: an introduced plant growing in ground that is or has been in cultivation usu. to the detriment of the crop or to the disfigurement of the place : an economically useless plant : a plant of unsightly appearance esp : one of wild or rank growth

Whorled: [Leaves] {insertion} With three or more leaves positioned on the stem at the same level; three or more leaves occurring at each node.

Winged: [2-4-year-old twigs, Petioles, Rachises] {special surface features} Having one or more elongate, relatively thin protrusions or appendages that loosely resemble wings, as the twigs of winged elm (Ulmus alata).

Woody: (1) [Plants] {woodiness} With an aboveground shoot composed of relatively hard tissue that persists from one growing season to the next.

Woody: (2) [Seed cone scales] {type} Of or resembling wood, and thus relatively hard and dry.

Wrinkled: [Apophyses] {texture} With small folds or creases.


Xerophyte: a plant structually adapted for life nd growth with with a limited water supply esp. by means of mechanisms (as epidermal thickening, waxy or resinous coats, or dense pubescence) that limit transpiration or that provide for the storabe of water -- u sed both of desert plants and of those occupying environments (as salt marshes or acid bogs) where water absorption is impeded by excess salts or acids in solution


Zoned: [Leaf lower surface, Leaf upper surface] {color variegation} The same as ocellated, but the concentric bands more numerous.

Zygomorphic: bilaterally symetrical specif: capable of division into esentially symmetrical halves by only onlongitudinal plane passing through the axis.

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