A
Abortive Lacking or defective
Abscission layer Layer of cells at base of leaf that, when developed, causes the leaf to die and eventually drop
Accessory An additional part
Achene A small, dry, one-seeded fruit
Acicular Needlelike
Actinomorphic Radially symmetrical; regular flower
Aculeate “Spiny” or “prickly” leaf margin
Acuminate Tapering gradually to a point
Acute Tapering rapidly to a point
Adnate Fusion of unlike parts of a flower (e.g. perianth and stamens, which form the hypanthium)
Agamospermy The asexual formation of a seed
Aggregate a cluster of fruits developed from separate pistils of a single flower and remaining together at maturity
Allelopathy The process in which a plant releases into the environment a chemical compound that inhibits or stimulates the growth of another plant in the same or neighboring habitat. In native plant communities allelopathy may determine distribution patterns of plants in relation to their associates; in forestry, allelopathy may also affect yields or forest regeneration. Some important allelopathic trees are black walnut, eucalyptus, sugar maple, hackberry, balsam poplar, and sassafras
Allergenic Causing an allergic reaction such as dermatitis or nasal bronchial irritation in susceptible individuals
Allogamy Cross-fertilization between flowers; including geitonogamy and xenogamy
Allopatric Two taxa with non-overlapping geographical ranges
Alternate Plant parts that are placed individually along a stem, in a zig-zag arrangement, one leaf at each node - not opposite each other
Ament the flowers of some trees are aggregated in conspicuous structures called aments or catkins appearing much like large buds. They consist of many reduced, unisexual flowers borne close together on a common axis, with subtending scales
Anastomosing Interlacing
Androecium The collective term for all the stamens of a flower
Androgynous Having both staminate and pistilate flowers in the same inflorescence
Anemochory Wind dispersal of diaspores
Anemophilous Wind-pollinated
Anueploid A chromosome number that is not an exact multiple of the base haploid number within a group
Angiosperm A class of plants characterized by the formation of flowers and seeds enclosed in fruits
Anther The pollen-bearing portion of the stamen
Anthesis The time of opening of a flower when pollination can occur
Apetalous Without petals
Apex The extreme top or tip of a plant part
Apiculate Abruptly pointed
Apomixis (apomictic) Asexual reproduction as a substitute for the normal sexual process
Apophysis The part of a cone scale that is exposed when the cone is closed
A posteriori Derived after observation of the facts
Appressed Pressed closely and flatly along the length of a plant part
A priori Derived by reasoning before the facts
Arborescent Treelike
Arcuate Arching, as in leaf venation when veins arch from the midrib and follow the margin back to the tip of the leaf
Aril A fleshy appendage growing from the point of attachment of a seed and often covering the seed
Aristate Bearing a stiff bristle at the apex
Articulate Joined or jointed
Artificial classification Based upon a few convenient characters and a priori reasoning
Asepalous Without sepals
Association A group of species occurring in the same habitat with one or more dominant species as well as associated species; often designated by the names of the dominant species (e.g. spruce-fir or pine-oak)
Attenuate Long, tapering; acuminate
Auriculate With earlike lobes at the base
Autoecology Ecology of an individual plant or species
Autogamy Self-fertilization; pollination within one bisexual flower
Awl (Awn) Subulate leaf type of conifers that are short, stiff, and tapered to a point
Axil The upper angle formed by a leaf petiole with the stem
Axile Situated on the axis
Axillary In an axil
Axillary bud The buds developed along the side of a twig are known as axillary buds or lateral buds
Axis The central line of an organ; the “stem” to which stricture are attached
B
Ballochory (autochory) Seed dispersal by ballistic means - being shot out of the fruit
Bark The tissues formed on the outside of a woody stem
Barochory Diaspore dispersal by weigh (gravity)
Base The bottom portion of an object
Basionym The name bringing synonym in any change in position or rank of a taxon
Bast Fibrous constituents of the bark
Berry The flesh fruit without a stone, usually containing many seeds embedded in the pulp
Bi- or Bis- Prefix denoting two, double, or twice
Bifib two-cleft; split into two parts
Bilibiate Two-lipped
Bipinnate More than one set of leaflets per leaf
Bisexual Having both sex organs in the same flower; perfect, monoclinous
Blade The flat, expanded portion of a leaf, lamina
Bloom White powdery layer on plant parts. Usually easily rubbed off
Bole Trunk of a tree
Boss (bossed) A raised projection, usually pointed but not prickly
Bract A modified leaf subtending a flower, branch of an inflorescence, or conifer cone scale
Bracteole A tertiary bract
Bractlet A secondary bract
Branch One of the divisions of the trunk
Bristle A stiff, thin hair which may be straight or hooked
Bud The undeveloped state of a branch, leaf and/or flower cluster, with or without hard scales
Bud scale Modified leaves forming a covering which protects the bud from drying out and other injuries
Bundle A cluster of plant parts
Bundle scars Marks within leaf scar produced when the petiole separates from the stem, indicating the broken ends of the xylem and phloem strands
Buttress Swollen base of a tree trunk
C
Cache A secure place of storage, as a hoard of nuts
Calicole (calicphile) A plant restricted to, or growing best on, alkaline soils
Calyx Collective term for all the sepals of a flower
Cambium Lateral meristem responsible for secondary growth
Campanulate Bell-shaped
Capitate Shaped like a head
Capsule A dry fruit with many seeds, opening near the tip
Carpel The basic unit of the gymnoecium; a simple pistil; the megasporophyll of a flower
Catkin A slender, pendulous, dense, flower cluster
Chambered A solid pith that is interrupted by uniformly spaced partitions of hollow spaces
Character A feature such as a leaf shape or bark color
Character state A particular character expression, such as ovate leaf shape or gray bark color
Ciliate Descriptive of a margin fringed with hairs
Cladistics A taxonomic approach to phylogeny emphasizing the branching of evolutionary lines and origin of character divergence
Cladogram Diagram of cladistic relationships
Cleft Divided into lobes separated by sinuses that extend more than halfway to the midrib
Climax The terminal community in ecological succession capable of self-replacement under the prevailing climatic, edaphic, physiographic, biotic, and pyric (fire) conditions
Cline A gradient of character states correlated with a geographical or ecological gradient
Clone A population of individuals propagated vegetatively or by apomixis from a single origin
Collateral Being side by side, as in buds on a stem
Comose Seeds with long hairs on the surface, as in cotton or cottonwood
Community All the organisms inhabiting a common environment and interacting with one another
Compilospecies A species that incorporates genes, and characters, from other species through hybridization
Complete A flower having sepals, petals, stamens, and carpels
Compound The leaf blade is divided into several separate sections called leaflets
Compessed Flattened
Concave Depressed or hollowed out
Cone The fruit of a conifer, usually with woody, overlapping scales. An aggregation of sporangia-bearing structures at the tip of a stem; best restricted to the conifers among seed plants
Conifer A cone-bearing tree
Coning Development and maturation of a cone; “flowering” in conifers
Connate Fusion of similar parts of a flower (e.g. sympetalous corolla)
Continuous Solid - no cavities or hollow spaces
Continuum A gradual change in species compositions along and environmental gradient
Convergent evolution The independent origin of similar features in different evolutionary lines due to similar adaptive pressures
Convex Arched
Cordate Heart-shaped
Coriaceous Thick and leathery
Cork Outer bark of the cork oak; generally the outer layer of bark
Corolla Collective term for all the petals of a flower
Corticolous Growing on the bark of tree trunks or branches
Corymb Short, broad, more or less flat-topped inflorescence, with branches arising spirally along the stem
Costa-palmate Leaf of some palms that appear fan-shaped but have a short midrib (costa)
Cove A sheltered valley between opposing slopes
Crenate A leaf margin with rounded, shallow teeth
Crenulate Finely crenate
Crown Upper part of a tree - the living branches with their foliage
Cultivar A horticultural variant, either selected from the wild or produced in cultivation, but maintained under cultivation; reproduced by either sexual or asexual means
Cuneate Wedge-shaped, tapering to a narrow base
Cupule A cuplike structure below or surrounding one or more nuts in the Fagaceae, formed by fusion of inflorescence axes bearing bracts that are modified into either scales (Quercus, Lithocarpus) or spines (Fagus, Castanea, Chrysolepis)
Cuspidate Abruptly tipped with a sharp, rigid point
Cyme Inflorescence consisting of a central rachis terminated early by a flower, then lower lateral branches developing and either ending with a flower or another cyme
Cymose Cyme-like
D
dbh (DBH) Diameter at breast height (4 ½ ft. or 1.3 m from the ground or 18 inches above butt swell)
Deciduous Plant having leaves that fall off each season
Decompound More than once divided or compounded
Decurrent Said of leaf base that extends down and is fused to the twig below the point of divergence; tree habit of diffusely branched, spreading form (deliquescent)
Decussate Opposite, 4-ranked leaf arrangement; each pair at right angles to the pairs above and below
Dehiscent Opening
Deliquescent Descriptive of a tree form lacking one central axis but rather with diffuse branches
Deltate Triangular or delta-shaped; “deltoid” is the three-dimensional form
Deltoid Triangular
Dentate Sharp teeth of margin pointed out, not forward
Denticulate Minutely dentate
Determinate short root Spur branch without a functional terminal bud
Diadelphous Stamens formed into two groups by fusion of the filaments
Diaspore The dispersed part of the plant; either seed, fruit, or cone
Dichotomous Y-branching: equal forking into pairs
Diclinous Flower that is unisexual; literally meaning “two couches”
Dicotuledonous (dicot) Having two cotyledons; members of the Magnoliopsida
Dimorphous Having two morphological forms
Dioecious Plant having unisexual flowers or cones; with only one sex per plant; literally meaning “two houses”
Disjunct A species population separated by a considerable distance from the main distributional range
Dissected Finely divided
Distichous Leaves all in one plane (i.e. in two ranks); either opposite or a ½ phyllotaxy if alternate
Divergent Bud sticks out, pointing away from stem
Double serrate Margin with large teeth, each tooth having smaller teeth
Downy Plant part is coated with soft hairs
Drupaceous Drupe-like
Drupe A simple, usually 1-seeded, fleshy fruit with the outer pericarp fleshy and the endocarp bony; a stone fruit
Druplet A small drupe
E
Echinate Armed with prickles
Ecology Branch of biology dealing with relationships between organisms and their environment
Ecophene A direct, non-genetic modification of a plant form by some environmental factor
Ecotone A transitional zone between two habitats and communities
Ecotype A heritable, morphological, or physiological form resulting from selection by an ecological condition
Eglandular Without glands
Ellisoid A three-dimensional form having the outline of an ellipse
Elliptic Widest at the middle, tapering equally to each end
Elliptical Plane figure resembling an ellipse, being widest at the center
Emarginate Apex with a shallow, broad notch
Embryo A young stage of the sporophyte plant in a seed
End bud the buds which terminate a twig are defined as end buds or terminal buds
Endemic A species restricted to a very limited, native, geographical area
Endocarp Inner layer of the pericarp (fruit wall)
Endosperm The food reserve outside the embryo within a seed; a postzygotic structure of Angiosperms
Endozoochory Diaspore dispersal by being eaten by animals and passing through the digestive tract
Entire Leaf edge (margin) has no indentations or teeth at all, completely smooth
Entomorphilous Insect pollinated
Epicormic A shoot arising from an adventitious or dormant bud on a stem or branch of a woody plant; coppice or “water” sprout
Epigeal (or Epigeous) Seed germination in which the cotyledons of the seedling are above the ground surface, as in maple or pine
Epigynous Perianth appearing to arise from above to ovary; often used to describe a flower with an inferior ovary
Epipetalous The fusion of filaments to the corolla; appearing as if the stamens
Erose Irregularly toothed, eroded or “chewed”
Estipulate Without stipules
Evergreen A woody perennial bearing foliage throughout the year
Excurrent Tree form with a main axis or trunk extending to the top of the crown and with secondary branches from the trunk
Exfoliate To peel or flake off in thin layers
Exocarp Outer layer of the pericarp (fruit wall)
Exozoochory Diaspore dispersal by being carried on the outside of any animal in fur or feathers, etc.
Exserted Extending out, beyond the surrounding structures
Extant Living at the present time
Extinct Eliminated entirely
Extirpated Eliminated from only a portion of the natural range
Extrorse Facing or opening outward
F
Falcate Sickle- or scythe-shaped
False whorl An apparent whorl of secondary branches in pines; considered “false” because the actual arrangement is a tight spiral
Family A level in the classification hierarchy between genus (below) and order (above); indicated by the suffix -aceae, pronounced -ay-see-ee
Fascicle A bundle or cluster
Fastigate A very narrow tree form having upright branches close to the trunk
Fertilization Union of male and female gametes
Filament The stalk of the stamen that supports the anther
Fimbricate-margined Appearing fringed
Fireblight an especially destructive bacterial disease on many species in the rose family, can be observed on blossoms, fruit, twigs, laves, limbs, and trunk of infected trees. A characteristic symptom of fireblight is the shepherd’s crook seen at the tip of young twigs.
Flabellate Fan-shaped
Flora The kinds of plants, taken collectively, that occupy a specified region
Flower Reproductive organ of an angiosperm
Fluted Regularly marked by alternating ridges and groove-like depressions
Foliaceous Leaf-like in appearance and texture
Follicle A single carpellate, dry fruit dehiscing along one line (suture)
Forest cover type A forest association, designated by the dominant species of trees
Formation One or more plant communities exhibiting a definite structure or life form occurring in similar habitats (e.g. grassland, marsh, conifer forest, or deciduous forest)
Fossil Remains of life of the geological past
Fruit A ripened, mature ovary
Fugacious soon falling or fading; not permanent
Furrowed Longitudinal ridges and grooves
Fusiform Spindle-shaped
G
Gallery forest A narrow forest along a waterway through a landscape otherwise devoid of trees
Gametophyte haploid phase of life cycle that produces the gametes
Geitonogamy Cross-fertilization between flowers on a single plant; genetically the same as autogamy
Genotype Genetic constitution of an individual
Genus/Genera the level in the classification hierarchy between family (above) and species (below)
Glabrate Becoming glabrous or nearly so
Glabrous No hairs, bristles or scales, smooth
Gland A tissue or protruding structure secreting oils, balsams or resins, usually on a leaf or petiole
Glandular Having glandular hairs; or the nature of a gland
Glaucescent Slightly glaucous
Glaucous Smooth and covered with a fine, white or blue powder (bloom) which can be rubbed off
Globose Round in form, or nearly so
Glochids Minute, barbed prickles in some cacti
Granular Minutely roughened
Gregarious Growing in clusters; colonial
Gymnosperm A class of plants that produce seeds not enclosed in an ovary or fruit but frequently in cones
Gynoecium Collective term for all the carpels of a flower
H
Habit General appearance of a plant as seen from a distance
Habitat The locality in which an organism lives
Halophyte A plant restricted to, or growing best in, high salt concentrations (salt flats, dunes, salt marshes)
Hammock An isolated area of southern hardwood forests on an elevated, well-drained site, surrounded by extensive pines or marsh; a hardwood forest on deep loamy soils rich in humus
Head A spherical or flat-topped inflorescence of sessile or nearly sessile flowers clustered on a common receptacle
Herbaceous Not woody, soft tissues
Herbarium A collection of plant specimens, pressed, dried, mounted on sheets, identified, and classified
Hesperidium Type of berry with a thick, leathery rind and many radial sections
Heteromorphism Having different forms of a structure, such as leaves
Heterophylly Having two or more different forms of leaves on the same plant
Hilum Scar or point of attachment of a seed
Hirsute With stiff or coarse hairs
Hoary With dense, grayish white hairs
Homoecious Plant with perfect flowers (synoecious)
Homoplastic similarity Similar characters in unrelated groups by convergent evolution
Hybrid A cross between two different plants (usually species)
Hybridization Process of crossing two unlike plants (usually species)
Hybrid swarm Population consisting of hybrids, backcrosses, and successive generations
Hydrochory Diaspore dispersal by water
Hypanthium Structure of a flower usually derived by adnation of perianth and stamens, forming a cup or tube; may be free of ovary (resulting in perigny) for fused with ovary (epigny)
Hypogeal (or Hypogeous) Seed germination in which the cotyledons of the seedling remain at or below the ground surface, as in oak or hickory
Hypogynous Perianth arising below the ovary; often used to describe a flower with a superior ovary
I
Imbricate Overlapping, like shingles on a roof
Imperfect Flower with only one sex; unisexual, diclinous
Inbreeding Crossing within a single plant; autogamy or geitonogamy
Incised Cut sharply and irregularly, to near the midrib
Incomplete Flower lacking one of the four whorls (calyx, corolla, androecium, gynoecium)
Indehiscent Not splitting
Indeterminate short root Spur branch having a functional terminal bud
Indigenous Native or original to an area
Inequilateral Asymmetrical base
Inferior ovary Ovary appearing below the perianth and stamens; the hypanthium fused with the ovary
Inflated Bladder-like
Infraspecific Classification categories below the species (subspecies, variety, forma)
Infructescence The arrangement of fruits on a branch system
Inserted Attached to or growing out of
Internode The space between nodes that is lacking leaves and buds, such as on a stem
Introgression (Introgressive hybridization) A flow of genes from one species to another across a fairly strong barrier to interbreeding by means of hybridization and backcrossing
Introrse Facing or opening inward
Involucral Belonging to an involucre
Involucrate Possessing an involucre
Involucre A cluster of bracts subtending a flower or inflorescence
Irregular Zygomorphic; bilateral symmetry in a flower
K
Keeled A prominent central ridge, like the keel of a boat
L
Laciniate Cut into lobes separated by deep, narrow, irregular incisions
Lactiferous Production of milky sap in certain species
Lamina Leaf blade
Lanceolate Tapering gradually from the base to a point; narrow and long
Lateral Situated or produced on the side
Layering Rooting from the lower side of branches
Leaf Appendage of a stem of a flat, veined blade and a stalk attaching the appendage to the stem
Leaf scar Scar left on a stem at the point where the leaf fell off
Leaflet One of the small, individual blades of a compound leaf
Legume A dry fruit from a single carpel, either dehiscing along two lines (sutures) or indehiscent
Lenticel A small breathing pore on the stems of plants, may be showing up as a different colored dot on the stem, somewhat corky
Lenticellate Having lenticels on the twig
Lenticular Shaped like a double-convex lens
Lepidote Covered with minute, flattened, peltate trichomes or glands
Liana Woody vine
Ligulate Strap-shaped
Linear Long and narrow nearly parallel sides
Lobe Rounded or pointed extensions of the leaf blade margin
Lobed Leaf cut from ¼ to ½ the distance from the margin to midrib; more generally, any degree of lobing
Long shoot Stem with normally elongated internodes
Lunate Crescent-shaped
Lustrous Shiny, glossy
M
Marcescence/Marcescent Leaves withering and turning brown but persisting on the tree
Margin The very edge of a leaf blade
Membranous Thin, more or less flexible
Meristem A localized plant tissue capable of cell division and giving rise to new cells and tissues
Merous Having a specified number of parts
Mesic Intermediate moisture regime, between xeric (dry) and hydric (wet)
Mesocarp Middle layer of the pericarp (fruit wall)
Midrib The mid or central vein of a leaf
Monadelphous Stamens united into a tube by the union of the filaments
Monoclinous Flower that is bisexual; literally meaning “one couch”
Monocotyledonous (monocot) Having but one cotyledon; members of the Liliopsida
Monoecious Plant with both male and female flowers or cones; literally meaning “one house”
Monotypic Having only one representative (e.g. monotypic genus has only one species)
Morphology Branch of biology dealing with form and structure
Mucro A short, abrupt tip of a leaf or cone scale
Mucronate Terminated by a mucro, bristle-tipped
Multiple Coalesced fruits of an infructescence
Mutation A change in the amount or structure of the genetic material; an inheritable change of a gene from one form to another
N
Naked bud Lacking a covering - as in a bud with no protective, hard scales
Natural classification Grouping based upon many characters of the plant and a posteriori reasoning
Naturalized An introduced plant, escaped from cultivation, and reproducing naturally for enough years to have become part of the flora
Naval stores Resin products used originally for ships, later for medicine and industry; tar and pitch are from burning resinous wood in the absence of air; turpentine and rosin are distillation products from resin collected from living trees
Needle Very narrow leaf, as in conifers - see also acicular
Nitrogen fixation The assimilation of atmospheric nitrogen into ammonia and nitrates by true bacteria or actinomycetes associated with the roots of certain plants
Node The place on a stem where buds and leaves arise, usually a swollen area on the stem
Nomenclature The naming of an organism
Nut An indehiscent, dry fruit, usually 1-seeded (though from a compound ovary), with a hard pericarp; sometimes partially or entirely encased in an involucre or husk formed of bracts
Nutlet Small nut
O
Oblanceolate Long and narrow but broadest near the tip
Oblique Lopsided
Oblong Longer than wide, with margin nearly parallel
Obovate Egg-shaped, broadest near the tip
Obtuse Blunt at the tip, almost rounded
Opposite Plant parts arise opposite each other along a central axis
Orbicular Circular or nearly so
Ornithophilous Bird-pollinated
Outcrossing Crossing between individuals; xenogamy
Oval Broadly elliptical with the width greater than ½ the length
Ovary The basal portion of a pistil that encloses the ovules
Ovate Egg-shaped, broadest below the middle
Ovoid Tree-dimensional structure with the shape of an egg
Ovulate Pertaining to the ovule, or possessing ovules
Ovule The structure that develops into a seed after fertilization of the enclosed egg
Ovuliferous scale A structure of a conifer scale in the axil of (and sometimes fused with) a bract and bearing one or more ovules
P
Palmate A type of compound leaf in which the leaflets are attached to a common point; with divisions spreading from a common center
Palmlike Tree form with an unbranched trunk and top rosette of leaves
Palynology A study of pollen and spores; either extinct or extant
Panduriform Fiddle-shaped; obovate with concave sides below the middle and with two small basal lobes
Panicle A branched flower cluster, the lower branches longest and flowering first
Paniculate In the form of a panicle
Papilionaceous (papinionate) Butterfly-like; descriptive of the flowers of the Fabaceae
Papillose Covered with minute, rounded projections from the cells
Parallel veins Any individual, free veins from base to apex of leaf
Parted Divided by sinuses that extend nearly to the midrib
Patristic similarity Similarity of characters derived from a common ancestor
Pectinate Comb-like; divided into long, narrow segments
Pedicel The stalk of an individual flower in an inflorescence
Pedicelled With a pedicel
Peduncle Stalk of a single flower as in magnolia; or, the stalk of an inflorescence (from base to first branch)
Peg Short projection on a conifer twig bearing a sessile or petiolate leaf and remaining on a twig following leaf drop
Peltate Shield-shaped and attached from the center by a supporting stalk; the shape of an umbrella
Pendant Drooping, hanging down - see also pendulous
Pendulous Hanging down, drooping
Penniveined Veined in a pinnate manner
Perennial Lasting for 3 or more years
Perfect Flowers with both sexes; bisexual, monoclinous
Perianth The collective term for both calyx and corolla
Pericarp Fruit wall, developed from the ovary wall
Periderm Outer bark; a protecting layer of cork cells; forming first just beneath the epidermis, later deeper in cortex or secondary phloem
Perigynous Perianth appearing to arise from a hypanthium surrounding but not fused to the superior ovary; often used to describe the flower with this structure
Persistent Remaining attached, not falling off after the growing period
Petal One unit of the corolla; inner perianth part
Petaloid Petal-like
Petiolate Having a petiole
Petiole The leafstalk which attaches the leaf blade to the stem
Petiolule The leafstalk of a leaflet in a compound leaf
Phentic classification Grouping based on overall similarity without regard to evolutionary relationships
Phenotype The evident characteristics of an organism due to the interaction of a genotype and environment
Phenotypic plasticity Non-heritable variation in characteristics; ecophenic variation
Phloem Conducting tissue, mainly of sieve-tube elements; inner bark
Phyllotaxy Leaf arrangement on a stem
Phylogeny/Phylogenetic Evolutionary history of a group
Physiognomy The general appearance of a plant community, based on external features (e.g. tall, evergreen trees; low, deciduous tree; pines savannah; or bog)
Pinnate Leaflets or veins arranged on each side of a common stem; feather-like
Pinnipalmte Leaf venation somewhat intermediate between pinnate and palmate in which the lowermost pair of secondary veins are slightly larger and with larger tertiary veins than the other secondaries
Pistil The evident ovary-style-stigma of a flower; a single separate carpel, or the fusion product of several carpels forming one compound pistil
Pistillate Flower with pistil(s) and without fertile stamens; female
Pith The central-most, softer portion of a stem
Pollen An immature stage of the male gametophyte with a hard, resistant cell wall; carried by some agent in the process of pollination
Pollination Transfer of pollen from pollen sac (or anther) to ovule (or stigma)
Polygamous Mixture of perfect and unisexual flowers and either mainly monoecious or dioecious
Pome A fleshy fruit from an inferior ovary with the hypanthium forming most of the fleshy structure
Prickle A needle-like outgrowth arising from the outer layer of stem, leaf or fruit cells e.g. rose
Provenance Origin; locality where found or collected; the forester’s term for a local race or ecotype
Pseudoterminal bud The distal lateral bud on a twig that assumes the function of the terminal bud; the twig apex is aborted; recognized by its adjacent leaf scar and aborted tip of the twig
Puberulent Minutely hairy, scarcely visible to the unaided eye
Pubescent Hairy or downy
Pulvinus/Pulvini The swollen base of a petiole functioning in turgor movements of the leaf
Pyriform Pear-shaped
R
Raceme Inflorescence with a central axis bearing pedicelled flowers
Rachilla Branch of the rachis
Rachis The lead stalk of a compound leaf
Receptacle The portion of the axis that bears the floral organs
Recombination The bringing together of chromosomes (and genes) as a result of fertilization and the formation of gene combinations in the offspring that differ from those of the parents
Recurved Curved downward or backward
Reflexed Abruptly bent or turned downward
Regular Actinomorphic; radial symmetry in a flower
Reniform Kidney-shaped; wider than long and with a broad cordate base
Repand Slightly and irregularly wavy
Resin An excretion product of certain plants
Resin cyst Cell or cavity (blister) with resin
Reticulate Net-like; many small irregular veins throughout a leaf
Retuse Apex with a shallow and narrow notch
Revolute Rolled back toward the lower side, as in a leaf margin
Rhombic Oval, but angular at the sides; diamond-shaped
Root Underground part of a plant which supplies the plant with nourishment, anchors the plant and is a storage area
Rosette A tight cluster of leaves, either basal or apical on a stem
Rufous Reddish brown
Rugose Coarsely wrinkled, uneven, rough
S
Samara A dry, winged, one-seeded, papery fruit
Samaroid samara-like
Savanna Grassland with widely spaced trees
Scabrous Rough to the touch
Scale Small, often appressed leaf, part of the conifer cone that bears ovules
Schizocarp Dehiscent fruit that splits into individual locules (carpels) each appearing as a simple fruit, as the schizocarpic samaras of maple
Scurfy Covered with minute scales
Seed A ripened ovule, following fertilization, and normally with an embryo
Segregation The separation of chromosomes (and genes) at the time of meiosis
Self-incompatibility Genetically determined inability for self-fertilization
Sensu According to; following
Sepal A unit of the calyx; outer perianth part
Serotinous Cones that remain closed long after the seeds inside are mature
Serrate Leaf edge (margin) composed of teeth pointing toward the tip of the leaf
Serrulate Minutely serrate
Sessile Without a stalk, sitting directly on the base
Sheath A tubular envelope possibly papery, clasping and enclosing other plant parts, such as the needles of a pine
Shoot A stem bearing foliage
Short shoot Short, lateral branch without internode elongation; either determinate or indeterminate
Shrub A woody perennial usually having more than one trunk
Simple In one piece; not divided into smaller units
Sinuate Shallowly indented, wavy in a horizontal plane
Sinus The recess or indentation between two lobes
Spatulate Spatula-shaped; elongated with widest point near rounded apex and tapering to the base
Speciation Formation of a species
Species The unit of the classification hierarchy below the genus; defined generally as a population of potentially interbreeding individuals set apart from another species by more or less consistent and persistent differences in morphology, ecology, and breeding behavior
Spike Inflorescence consisting of a central axis bearing sessile flowers
Spine A sharp thin modified leaf, arising from a node on the stem, just like a leaf would, e.g. cactus
Spinose Spine-like or with spines
Spiral Leaf arrangement on a stem that winds around from base to apex; alternate
Sporophyte Diploid phase of the life cycle that includes the vascular plant
Spray Flattened, frond-like branchlets in some conifers
Spur A short, compact branch with no internode elongation; short shoot - see spur shoot
Spur shoot A short, stubby branch, bearing leaves, flowers or fruit
Stamen The basic unit of the androecium; microsporophyll of a flower
Staminate Flower with stamens and without fertile pistils; male
Stellate start-shaped
Stem The leaf and flower bearing part of a plant
Sterigma/Sterigmata woody pegs - see pegs
Sterile Lacking reproductive structures
Stigma Top part of the pistil that is receptive to pollen
Stipulate with stipules
Stipule A leafy appendage at the base of a petiole, usually one at each side
Stipule scar The scar left on the stem when the stipule falls off
Stomata Breathing pores in leaves
Striate With fine grooves, ridges, or lines of color
Strigose Having stiff, straight, appressed hairs, usually, pointing the same direction
Strobilus/Strobili A small cone or cone-like structure
Style Slender part of a pistil between the ovary and stigma; if lacking, then the stigma is sessile
Sub-opposite Almost opposite, not quite
Subulate Short, narrow, tapered, sharp-pointed leaf; awn or awl
Succession The sequential process of community change; the sequence of communities that replace one another in a given area culminating in a climax community
Succulent Juicy, pulpy, fleshy
Sucker An extra sheet arising above ground from a root
Superior ovary Ovary above the origin of the perianth and stamens
Superposed One bud above another
Suture Line of dehiscence
Sympatric Two or more taxa with overlapping geographical ranges
Sympetalous With petals fused
Syndrome A Number of characteristics occurring together and characterizing a specific function or adaptation
Syngameon The most inclusive group of introgressing species
Synoecious Plant with perfect flowers (homoecious)
Synonym A rejected plant name that is replaced by another for some nomenclatural or taxonomic reason
Synozoochory Diaspore dispersal by animals collecting seeds or fruits for a cache or for burying
Systematics Study of the diversity of organisms including description, classification, nomenclature, and evolutionary relationships
T
Taxon/Taxa General term for any taxonomic group, at any unspecified level of the classification hierarchy
Taxonomy see systematics
Tendril A modified leaflet, leaf, stipule or branch used as a lateral climbing organ by the plant
Tepal Undifferentiated perianth part, separate or fused
Terete Circular in cross-section
Terminal Situated at the end or tip
Terminal bud Bud that terminates the twig; lacking an associated leaf scar
Terminal bud scale scar The scar remaining on a stem after a bud has elongated and the bud scales have fallen off
Ternate in threes
Thorn A modified stem, hard and sharp-pointed, arising from a node, e.g. hawthorn
Tomentose Densely woolly, hairy
Tomentum The dense, matted hairs of a tomentose condition
Tree A woody perennial with one main trunk
Trichome Any type of hair on the surface
Trichotomous Tree-forked
Trident Tree-toothed
Trifoliate Three leaflets, or leaves arranged in threes
Trigonous Tree-angled
Tripinnate Tree-times pinnate
Truncate As though cut off at a right angle to the midrib
Turbinate Top-shaped
Twig the last year’s growth of a woody stem
Type specimen A specimen designated to serve as a reference point for a scientific name (species or infraspecific taxon); it is not necessarily the most typical. The type of a genus is a species; the type of a family is a genus and the one that forms the root of the family name
U
Umbel Inflorescence, often flat-topped, consisting of several pedicelled flowers all attached at the same point at the top of the peduncle
Umbellate Umbel-like
Umbo A protruberance, as on the apophysis of a cone scale
Undulate Wavy in a vertical plane; crisped
Unifoliate A leaf having only a single leaflet; usually described as “simple”
Unisexual Having only one sex; either diclinous flowers or dioecious plants
V
Valvate Meeting at the edges, not overlapping
Valve One of the sections into which dehiscent fruits are split
Vascular With xylem and phloem tissues
Vein A strand of conducting tissue in a leaf. Continuation of the xylem and phloem from the stem, through the petiole, into the leaf
Venation Arrangement of veins within the leaf
Vernal Appearing in spring
Verticillate Whorled
Villous With long, silky, straight hairs
W
Whorl The arrangement of leaves in groups of three or more at nodes
Wood Secondary xylem
Woolly With long, matted hairs
X
Xenogamy Cross-fertilization between flowers on different plants; outcrossing.
Xeric Dry
Xerophyte A plant adapted to dry conditions
Xylem Conducting tissue formed mainly of tracheids or vessels and tracheids
Z
Zygomorphic Bilaterally symmetrical; irregular flower