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A

Achene: [Fruits] {type} A more or less small, dry fruit that does not split open at maturity (indehiscent), with a typically thin, close-fitting wall surrounding a single seed.

Acicular: [Leaflets, Leaves] {shape} Very long and slender, gradually tapering to a point, like a needle; needle-shaped.

Acorn: [Fruits] {type} A nut with a persistent, cup-like structure (cupule) attached at the base consisting of numerous partially fused, overlapping, dry bracts, as in oaks (Quercus).

Actinomorphic: radially symmetrical -- used of organisms, organs, or parts capable of division into essentially symmetrical; halves by any longitudinal palne passing through the axis

Acuminate: [Leaf apices, Leaflet apices, Petal apices, Phyllary apices, Sepal apices] {shape} Gradually tapering to a sharp point, forming concave sides along the tip.

Acute: [Leaf apices, Leaflet apices, Petal apices, Phyllary apices, Sepal apices] {shape} Tapering to a pointed apex with more or less straight sides, the sides coming together at an angle of less than 90:.

Adnate: grown together, used especially of unlike parts

Adventitious: (1) Structures or organs arising in a position that is unusual for their type, as roots originating on the stem.

Adventitious: (2) [Roots] {type} Roots arising from any part of the plant (e.g. stem or leaf) other than the root system; usually growing laterally, often from the lower part of the main stem.

Aerial stem: [Stems] {type} A prostrate to erect, above ground stem.

Aggregate: of a flower clustered in a dense mass or head; of a fruit : formed from the several separate or fused ovaries of a single flower

Aggregate fruit: [Fruits] {type} A cluster of fruits that stick together or are fused, originating from two or more separate pistils contained within a single flower, as in jackfruity (Artocarpus).

Alternate: [Leaves] {insertion} Positioned singly at different heights on the stem; one leaf occurring at each node.

Ament: an indeterminate spicate inflorescence bearing scaly bracts and apetalous unisexual flowers (as in the willow)

Androecium: A collective term for all the stamens and any closely associated structures in a flower.

Angiosperm: [Plants] {major group} Plants that bear their seeds enclosed in an ovary; the flowering plants.

Annual: [Plants] {life span} Normally living one year or less; growing, reproducing, and dying within one cycle of seasons.

Anther: The pollen-producing portion of the stamen typically borne at the tip of a stalk or filament.

Anthocarp: a fruit with some portion of the flower besides the pericarp persisting, as in a pome with the fleshy perianth tube surrounding the pericarp (h)

Apex: The portion of a plant structure (such as a leaf, bud, stem, etc.) farthest from its point of attachment or uppermost; the tip.

Apical: [Placentation] {type} Attachment of ovules at the top or apex of the ovary.

Apiculate: [Leaf apices, Leaflet apices, Petal apices, Phyllary apices, Sepal apices] {shape} Ending abruptly in a small, slender, point that is not stiff and often slightly curved.

Apocarpous: having the carpels of the gynoecium separate

Apopetalous: [Corolla] {fusion} With petals distinct, not fused.

Apophysis: The outer portion of a cone scale which is exposed when the cone is closed.

Aposepalous: [Calyx] {fusion} With sepals distinct, not fused.

Appressed: [Leaves, Petals, Phyllaries, Sepals] {vertical orientation} Pressed upwardly close or flat against the bearing structure, thus more or less parallel to it.

Aquatic-emergent: [Plants] {habit} Growing in water with stem and leaves extending above the surface.

Aquatic-floating: [Plants] {habit} Growing in water with leaves floating on the surface.

Aquatic-submerged: [Plants] {habit} Growing in water with stem and leaves beneath the surface.

Arachnoid: [Buds, Leaf lower surface, Leaf upper surface, Phyllaries, Sepals, Young twigs] {pubescence type} With fairly sparse, fine, white, loosely tangled hairs; cobwebby.

Areole: a small pit or cavity (as that from which spines arise in cacti)

Aril: an exterior covering or appendage of certain seeds that develops after fertilization as an outgrowth from the funiculus and envelopes the seed

Aristate: [Leaf apices, Leaflet apices, Petal apices, Phyllary apices, Sepal apices] {shape} Bearing a prolonged, slender, stiff, usually straight tip; awned or bristled.

Armature: Any kind of sharp defense such as thorns, spines, or prickles.

Armed: (1) [Bark of mature trunks] {surface appearance} Bearing any kind of sharp defense such as thorns, spines, or prickles.

Armed: (2) [Seed cone scales] {armature} Bearing a hook, prickle or other sharply pointed structure on the end of the cone scale.

Ascending: [Leaves, Petals, Phyllaries, Sepals] {vertical orientation} Spreading at the base and then curving upward to an angle of 45: or less relative to the bearing structure.

Astringent: Foliage with a soapy or medicinal aroma because of the presence of saponins and other chemicals.

Asymmetric: (1) [Calyx, Corolla] {symmetry} Not divisible into essentially equal halves along any plane.

Asymmetric: (2) [Seed cones] {symmetry} Not divisible into essentially equal halves along any plane.

Attenuate: [Leaf bases, Leaflet bases] {shape} Tapering gradually to a narrow base.

Auriculate: [Leaf bases, Leaflet bases] {shape} With ear-shaped appendages at the base.

Autotrophic: [Plants] {nutrition} Able to synthesize the nutritive substances an organism needs from the non-living environment; in plants, photosynthetic.

Awl-shaped: [Leaflets, Leaves] {shape} Narrowly triangular and sharply pointed, like an awl.

Awn: A slender, more or less straight and stiff, fine-pointed appendage; may be located at the tip of a leaf or bract and a continuation of the midvein, or comprising the pappus in fruits of the sunflower family (Asteraceae).

Axil: The point of the upper angle formed between the axis of a stem and any part (usually a leaf) arising from it.

Axile: [Placentation] {type} Attachment of ovules at or near the center of a compound ovary which has more than one inner compartment (multilocular), the ovules located on the inner angle formed by the interior partitions (septa).

Axillary: [Buds, Inflorescences, Seed cones] {position} On the stem just above the point of attachment of a leaf (or leaf scar) or branch; borne in the axil of a leaf or branch.

Axis: Any relatively long, continuous, supporting structure that typically bears other organs laterally, and represents the main line of growth and/or symmetry; as a stem that bears leaves or branches, or the rachis of an inflorescence that bears flowers along its length.

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B

Banded: [Leaf lower surface, Leaf upper surface] {color variegation} Transverse, or
horizontal, stripes of one color crossing another.

Bark: The outermost layer of a woody stem, usually with one or more corky layers that prevent water loss and protect the inner living tissues from mechanical damage.

Basal: (1) At or very near the base of a plant structure.

Basal: (2) [Leaves] {position} With leaves arising at or near the base of the stem.

Basal: (3) [Placentation] {type} Attachment of ovules at the base of the ovary.

Base: The portion of a plant structure (such as a leaf, bud, stem, etc.) nearest the point of attachment or lowermost; the bottom.

Beak: This is a pointed slender appendage that defines the outer tip of a seedpod; the seedpods of many plant species lack beaks. For Carex spp. (Sedges), this term has a different meaning. The perigynium of a Carex sp. can have a slender beak at its apex to enclose the long style of a female floret, or the perigynium can be nearly beakless when the style of the female floret is quite short.

Berry: [Fruits] {type} A fleshy fruit that does not split open at maturity (indehiscent), with few or more seeds (rarely just one), the seeds without a stony covering; the flesh may be more or less homogenous or with the outer portion more firm or leathery; as grapes (Vitis).

Biconvex: convex on both sides

Biennial [Plants] {life span} Normally living two years; germinating or forming and growing vegetatively during one cycle of seasons, then reproducing sexually and dying during the following one.

Bifoliolate: [Leaves] {complexity form} Compound with two leaflets; two-leafleted or geminate.

Bifurcated: A structure that is divided into two parts along some portion of its length. This often refers to petals that are deeply notched at their tips, as occurs in the flowers of Stellaria spp. (Chickweeds) and Cerastium spp. (Mouse-Eared Chickweed).

Bigeminate: [Leaves] {complexity form} With two orders of leaflets, each divided into pairs or geminately compound; doubly paired.

Bilabiate: having two lips

Bilaterally symmetric: [Calyx, Corolla] {symmetry} Divisible into two essentially equal portions along only one plane.

Bipalmately compound: [Leaves] {complexity form} With two orders of leaflets, eachpalmately compound; twice palmately compound.

Bipinnate: twice pinnate

Bipinnately compound: [Leaves] {complexity form} With two orders of leaflets, each pinnately compound; twice pinnately compound.

Bipinnately lobed: [Leaves] {lobing form} With two orders of leaf lobing, each pinnately lobed; twice pinnately lobed.

Bipinnate-pinnatifid: [Leaves] {complexity form} Twice pinnately compound with pinnatifid leaflets.

Bipinnatifid: A simple leaf or leaflet that is pinnatifid with lobes along its side margins; these lobes are also pinnatifid with secondary lobes along their margins. Some species of ferns have bipinnatifid leaves; the lobes of such leaves are often cleft.

Bisexual: (1) Having functional reproductive structures of both sexes (i.e. male and female) in the same flower or cone.

Bisexual: (2) [Flowers] {gender} Having functional reproductive structures of both sexes (i.e. male and female) in the same flower.

Biternate: [Leaves] {complexity form} With two orders of leaflets, each divided into threes or ternately compound; twice trifoliolate.

Blade: The flat, expanded portion of a leaf, petal, sepal, etc.

Blade-like: [Stipules] {type} Expanded and flattened, as the main portion or blade of a broad leaf.

Blotched: [Leaf lower surface, Leaf upper surface] {color variegation} The color disposed in broad, irregular blotches.

Bordered: [Leaf lower surface, Leaf upper surface] {color variegation} One color is surrounded by an edging of another.

Boreal: of, relating to, or constituting a terrestrial biogeographic division comprising the northern and mountainous parts of the northern hemisphere in which mean temperature during the six hottest weeks does not exceed 64.4o F. and being equiva lent to the Holarctic region exclusive of the Sonoran and Transition zones and corresponding Old World areas

Brachiate: having widely spreading branches arranged in altenating pairs

Bract: A modified, usually reduced leaf, often occurring at the base of a flower or inflorescence.

Bracteole: a small bract; esp one on a floral axis -- called also bractlet

Branch: A division or subdivision of a stem or other axis.

Branchlet: An ultimate branch, i.e. one located at the end of a system of branches; a small Branch.

Bristle: A slender, more or less straight and stiff, fine-pointed appendage; may be located at the tip of a leaf or bract and a continuation of the midvein, or comprising the pappus in fruits of the sunflower family (Asteraceae).

Broadleaf herbaceous: [Plants] {habit} Herbaceous with relatively broad leaves, thus differing from the long, narrow leaves of grasses (Poaceae) and other grass-like plants .

Broad-leaved: [Leaves] {general form} With leaves that are not needle-like or scale-like, but having relatively broad, flat surfaces, as in most deciduous trees such as maples (Acer).

Bud: An immature shoot, either vegetative, floral or both, and often covered by protective scales.

Buffered: in the case of Nymphaeaceae plants are protected from extreme fluctuations in temperature by the slower rate of change in the body of water (nb)

Bulb: [Stems] {type} A short, vertical, usually underground stem with fleshy storage leaves attached, as in onions (Allium cepa).

Bulbets Small bulbs that are produced underground or above ground as an alternative to seeds. Above ground bulbs are produced in the inflorescence and are called "aerial bulbets." Such bulbets are often produced by some Allium spp. (Onions).

Bulrushes A common name that refers to species in the genus Scirpus. Because Scirpus spp. (Bulrushes) are members of the Cyperaceae (Sedge family), they are actually sedges, notwithstanding the common name.

Bundle scar: A small scar within a leaf scar left by a vascular bundle that previously entered the stalk (petiole) or base of the fallen leaf.

Bur: [Fruits] {type} A cypsela or other fruit enclosed in a whorl of dry bracts (involucre) covered with spines or prickles that are often hooked, aiding in their dispersal by animals, as in cocklebur (Xanthium).

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C

C3 Metabolism: Cool-season plants use a C3 metabolism to convert sunlight into carbohydrates using chlorophyll. They often grow best during the spring or fall when the weather is cool and moist. Most forbs and some grasses and sedges have a C3 metabolism. The chemical pathway of C3 metabolism is slightly different from that of C4 metabolism (see the description below).


C4 Metabolism: Warm-season plants use a C4 metabolism to convert sunlight into carbohydrates using chlorophyll. These plants often grow best during the summer when the weather is warm and somewhat dry. Some grasses and most Cyperus spp. (Flat Sedges) have a C4 metabolism. The chemical pathway of C4 metabolism is slightly different from that of C3 metabolism (see the description above).

Caducous: [Petals, Sepals, Stipules] {persistence} Falling off very early, as stipules that drop soon after the leaf develops.

Calyx: The collective term for all of the sepals of a flower; the outer perianth whorl.

CAM: Crassulacean Acid Metabolism

Canescent: [Buds, Leaf lower surface, Leaf upper surface, Phyllaries, Sepals, Young twigs] {pubescence type} Gray or white in color due to a covering of short, fine, gray or white hairs.

Capitulate: collected into small capitula

Capitulum: a simple racemose inflorescence in which the primary axis is shortened and dilated forming a rounded or flattened cluster of sessile flowers (as in the buttonbush and in all composite plants) -- called also head

Capsule: [Fruits] {type} A dry fruit that opens (dehisces) in any of various ways at maturity to release few to many seeds.

Carnivorous: [Plants] {carnivory} Capturing animals (usually insects), digesting their tissues and assimilating the digested substances as nourishment, especially nitrogen. [

Carpel: The basic ovule-bearing unit of flowers, thought to be evolutionarily derived from an infolded leaf-like structure; equivalent to a simple pistil or a division of a compound pistil.

Carpophore: a slender often forked prolongation of a receptacle or pistil or both which develops as the fruit ripens and from which the ripened carpels are suspended (as in members of the genus Geranium and in the Umbelliferae)

Caryopsis: [Fruits] {type} A more or less small, dry fruit that does not split open at maturity (indehiscent), with a thin wall surrounding and fused to the single seed, as the fruits of the grass family (Poaceae); a grain.

Catkin: [Inflorescences] {type} A pendent, more or less flexible, spike-like inflorescence with numerous small flowers, typically of only one sex (unisexual), lacking petals and subtended by scaly bracts, as in willows (Salix) and birches (Betula); catkins are often wind pollinated and fall as a unit after flowering or fruiting.

Caudate: [Leaf apices, Leaflet apices, Petal apices, Phyllary apices, Sepal apices] {shape}

Caudex: This is a spheroid enlargement at the base of a plant that is usually below the surface of the soil (in herbaceous plants). A caudex is woody and functions as a storage organ for nutrients and water. One or more stems develop from the top of a caudex, while coarse roots radiate below. See line drawing of a Caudex.

Cauline: [Leaves] {position} With leaves positioned along the stem above ground level.

Central Axis: This expression usually refers to the central stalk of an inflorescence that is a spike, raceme, or panicle. Sometimes it refers to the central stalk (or rachis) of a compound leaf.

Cereal: a plant (as a grass) yielding farinaceous seeds suitable for food (as wheat, maize, rice)

Chambered: [Pith] {type} Interrupted by more or less regularly spaced cavities.

Checkered: [Bark of mature trunks] {surface appearance} Bark divided into small squarish plates, resembling alligator leather, as in flowering dogwood (Cornus florida).

Ciliate: [Leaf margins, Leaflet margins, Petal margins, Phyllary margins, Sepal margins] {form}; [Buds] {pubescence type} With a fringe of hairs along the margin.

Circular: [Leaf cross section] {shape} Round in cross section.

Circumferential: [Stipules, Stipule scars] {extent} Encircling the twig.

Circumscissile: dehiscing by a transverse fissure around the circumference

Circumscissile capsule: [Fruits] {type} A capsule that splits open (dehisces) by a horizontal line around the fruit, the top coming off as a lid.

Clasping: [Leaf bases, Leaflet bases] {shape} The base partly surrounding the stem.

Claw: the slender, prolonged basal portion of certain petals (as in the pink)

Clawed: having claws (see above)

Cleft: The leaf is sharply divided into lobes; it may be pinnately or palmately cleft. The ends of the lobes are often pointed, rather than rounded. See line drawing of Cleft shape.

Circinate: characterized by hor having the form of a flat coil of which the apex is the center -- used esp. of arrangements of plant parts in vernation and of developing fern fronds

Clouded: [Leaf lower surface, Leaf upper surface] Colors are unequally blended together.

Clustered: [Leaves] {insertion}; [Needles] {presence of clusters or fascicles} Leaves grouped closely together at the point of attachment and tending to diverge from one another, as the leaves on short shoots in Gingko (Gingko biloba) or the needles on short shoots in larches (Larix).

Collateral: [Buds] {position} In pairs, within or straddling the leaf axils; often located on either side of an axillary bud.

Column: the united monadelphous stamens in mallows b : the united androecium and gynoecium in orchids

Composite Flower: A flowerhead consisting of numerous small florets. This flowerhead may have ray florets (a small flower resembling a petal) and/or disk florets (a small tubular flower with tiny lobes). The florets are held together by floral bracts surrounding the base of the flower.

Compound: [Leaves] {complexity} Divided into two or more equivalent parts, as a leaf that consists of multiple, distinct leaflets; not simple.

Compound dichasium: [Inflorescences] {type} A determinate, cymose inflorescence with the main axis bearing a terminal flower and a pair of opposite or nearly opposite lateral branches, each branch also bearing a terminal flower and a pair of lateral flowers or branches; a branched dichasium.

Compound ovary: An ovary formed by the fusion of the bases of two or more carpels; recognizable by the presence of more than one area of placentation, locule, ovary lobe, style (or style branch), or stigma.

Compound umbel: [Inflorescences] {type} An inflorescence composed of several branches that radiate from almost the same point, like the ribs of an umbrella, each terminated by a secondary set of radiating branches that end in one or more flowers, the upper surface of the whole inflorescence rounded, or more or less flat; a branched umbel; as in Queen Annes lace (Daucus carota).

Cone: Reproductive structures in conifers comprised of scales and/or other types of modified leaves densely arranged on a central stalk; female, or seed cones, bear ovules on the surface of their scales; male cones produce pollen.

Conic: [Buds] {shape}; [Seed cones] {shape before opening, shape when open} Rounded in cross section, broadest at the base and essentially triangular in outline; cone-shaped.

Conifer: Cone-bearing plants, such as pines (Pinus).

Conspicuous lenticels: [Bark of mature trunks] {surface appearance} Bark with readily visible pores or lenticels.

Continuous: [Pith] {type} Uninterrupted by cavities and essentially homogenous in texture; solid.

Cordate: [Leaf bases, Leaflet bases, Leaflets, Leaves] Heart-shaped, with the notch at the base.

Corm: [Stems] {type} A short, solid, vertical, usually underground, enlarged stem with leaves that are dry and scale-like or absent.

Corolla: The collective term for all of the petals of a flower; the inner perianth whorl.

Corona: an appendage or series of united appendages borne on the inner side of the corolla in certain flowers (as in the daffodil, jonquil, and milkweed) and often resembling an additional whorl of the perianth

Corymb: [Inflorescences] {type} A racemose inflorescence with the individual flower stalks (pedicels) progressively shorter toward the apex so the flowers are all at about the same level, forming a flat or rounded surface across the top.

Cotyledon: the first leaf or one of the first pair or whorl of leaves developed by the embryo in seed plants and in ferns and related plants that functions primarily to make stored food in the endosperm available to the developing young plant but in some cases acts as a storage or photosynthetic organ

Creeping: tending to spread over the ground or other substrate

Crenate: [Leaf margins, Leaflet margins, Petal margins, Phyllary margins, Sepal margins] {form} With rounded teeth along the margin; scalloped.

Crenulate: [Leaf margins, Leaflet margins] {form} With very small, rounded teeth along the margin; finely crenate or small-scalloped.

Crisped: [Leaf margins, Leaflet margins] {form} Margins divided and twisted in more than one plane, as parsley (Petroselinum crispum) leaves; curled.

Cross-shaped: two intersecting lines or bars usu. of equal or approximately equal length and crossing at or about their midpoints

Crumpled: wrinkled, creased, or bent out of shape by or as if by pressing, folding, or crushing

Culm: the jointed stem of a grass usu. hollow except at the often swollen nodes and usu. herbaceous except in the bamboos and other arborescent grasses; also one of the solid stems of sedges, rushes, and similar monocotyledonous plants

Cuneate: [Leaf bases, Leaflet bases] {shape} Wedge-shaped and tapering to a point at the base.

Cupule: A cup-like structure at the base of some fruits, such as the acorns of oaks (Quercus), composed of a persistent, usually dried, whorl of bracts (involucre) or other sterile floral parts, that are often partially fused.

Cyathium: [Inflorescences] {type} An inflorescence consisting of a single, naked, terminal pistillate flower with several tiny, naked, lateral staminate flowers, the whole more or less enclosed by a cuplike whorl of bracts (involucre) and resembling a single flower; as in poinsettias (Euphorbia).

Cylindric: [Buds] {shape}; [Seed cones] {shape before opening, shape when open} Rounded in cross section with a more or less uniform diameter and blunt ends; cylinder-shaped.

Cyme: [Inflorescences] {type} Generally, a determinate, compound, and frequently more or less flat-topped inflorescence; the basic cymose unit is a three-flowered cluster composed of a main stalk bearing a terminal flower and below it, two stalked, lateral flowers, each with a reduced leaf or bract at the base.

Cymose: In the form of a simple or compound cyme; bearing cymes.

Cypsela: [Fruits] {type} A dry, one-seeded fruit that does not split open at maturity (indehiscent), with persistent perianth tissue (pappus) attached at the top, as in some members of the Asteraceae.

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