Botanical Dictionary

Word Definition Image
Abaxial The part of the organ not facing the axis.
Aberrant Not typical, not of the normal type.
Absciss Scar tissue formed when organs are shed.
Abscission layer This is a layer of cells that develop across the peduncle or petiole that becomes weak allowing the leaf or flower to fall off.
Acanthophyll A large spine normally derived from a leaflet.
Acaulescent With out a stem or appears to have no stem.
Accrescent A part of the plant that increases in size, as in the calyx after flowering.
Accumbent When cotyledons are adjacent to the radicle.
Achlamydeous A flower with out a perianth as in Salix species.
Acicle A stiff bristle or slender prickle that may have a gland at its apex.
Acid Soils A soil with a pH value lower than 6.5
Acidophile A plant that thrives in acid soils.
Acorn The fruit type/nut fruit of the genus Quercus
Acrogen A flowerless plant that only grows from the tip as in a fern.
Acropetal A plant that develops flowers that open in succession from the base.
Acroscopic A plant that is one sided towards the apex.
Acrotonic Where the greatest growth of branching is towards the apex.
Actinomorphic The flower being mirror imaged when divided through the centre in longitudinal planes.
Aculeate Having prickles.
Acyclic When arranged spirally rather than whorled.
Adaxial On the side facing the stem or axis.
Adherent When plant parts are in close contact but not fused with each other.
Adnate Dissimilar organs joined or attached to each other.
Adventitious Bud A bud that occurs from any part of the plant, apart from the stem apex or a leaf axil.
Adventitious Root A root that occurs from any part of a plant other than the primary root system.
Adventive A plant that has naturalised in a region but is not native.
Aerenchyma Water plants with tissues that have large air spaces in the roots or stems.
Aerial Root An adventitious root that will not usually contact the ground as in, epiphytic plants.
Aerotropic Turning towards or away from a source of oxygen.
Aestivation Is the arrangement of the calyx or corolla in bud.
After-ripening A term that describes the physiological changes after harvest that allows the seed to germinate.
Aggregate Fruit A fruit that is formed by joined carpels, that are separate in flower.
Alate (Winged) Having a wing or wings.
Albumen The nutritive material stored in a seed.
Alkaline Soils Soil types with a pH above 7.5
Allogamy (Cross Fertilisation) When the ovule of a flower is fertilised by pollen of a different flower.
Ament (Amentum Catkin) A spicate, normally pendulous inflorescence of unisexual apetalous flowers.
Amentum A spike of unisexual apetalous flowers with bracts and arranged in a catkin.
Amplexicaul Clasping the stem but not completely encircling it.
Anastomosing Connected by cross-veins and forming a network close towards the margins.
Anastomosis When veins cross connect in a leaf, producing a denser network towards the margin.
Anatomy The study of the structure of plants, based on dissection.
Ancipitous Having two edgedand being flattened, as in pseudobulbs of 'Laelia rubescens'.
Androecium The male parts of a flower; the stamens.
Androgynophore Column on which stamens and carpels are borne.
Androphore The receptacle extension above the calyx, appearing as a short stalk and bearing the corolla, stamens, and ovary. (elongated receptacle)
Anemochorous When seed or fruit are dispersed by wind.
Angiosperm Plant producing seeds enclosed in an ovary.
Anisophyllous When a pair of leaves differ in size or shape.
Annual Completing a life-cycle from seed germination to seed production within twelve months.
Annular Ring-like.
Annulus A group of cells in a fern that are located in the sporangium to control the release of spores.
Anther Pollen-containing part of a stamen.
Anthesis (Efflorescence) The flowering time.
Anthocarp A structure with a fruit, which is enclosed in a persistent perianth.
Anthophore The receptacle extension above the calyx, appearing as a short stalk and bearing the corolla, stamens, and ovary.
Antrorse When pointing forward or upwards.
Aperture An opening that is normally circular.
Apetalous Without petals.
Apex (plural Apices) The tip of an organ, normally referring to leaves.
Apical Pertaining to the apex.
Apical Placentation Describing the position of a placenta when located at the top of the ovary and with the ovules hanging down from it.
Apiculus Describing a short sharp point.
Apocarpous Having free carpels.
Apomixis Production of seed without sexual fusion of reproductive cells.
Appendage An additional attached part.
Appressed Closely and flatly pressed against.
Aquatic A plant that lives in water or in waterlogged soils.
Arborescent Having a tendency to become a tree. (A vine that becomes self supporting).
Arching or Arcuate Bending over or curved.
Areole A small area on the leaf that is surrounded by reticulate venation or commonly a condensed or modified short shoot growing in the leaf axil that has a felted cushion bearing spines.
Aril Often fleshy outgrowth, from the stalk or scar left by the stalk of the seed; related structures are called arillodes, caruncles and strophioles.
Arista An awn or stiff bristle.
Ascending When sloping or curved upwards.
Asepalous Without sepals.
Asexual Reproduction: No fusion of male and female cells.
Assimilatory To convert inorganic substances into the constituents of the plant system.
Assurgent To rise upwards.
Asymmetrical Not symmetrical; lop-sided.
Attenuate Becoming gradually narrow.
Atypical Not conforming to type.
Auricle Ear-like projection at the base of a leaf, stipule or bract.
Autochory When a plant disperses seeds by its self as in explosive or ejective mechanism.
Autogamy When a flower pollinates its self (self fertilisation).
Autumn The third season of the year, between summer and winter. Also known as 'Fall', relating to the loss of leaves from deciduous plants.
Auxin A plant hormone that controls the growth and development of a plant.
Awn Stiff extension, usually from the tip of an organ.
Axil The angled area that is formed between parent structure and a plant part, for example; where a leaf joins the stem.
Axil ( adj. Axillary) Type of placentation of ovules situated on a central axis of an ovary having two or more chambers. It is also the angle that is formed between the upper side of the petiole and the stem.
Axis (pl. Axes) Central stem of a plant or an inflorescence, or elongated part of receptacle on which floral organs are situated.
Baccate Berry-like.
Barb The wife of Herb or a hooked hair.
Bark A term describing the tissue outside the cambium of a woody stem.
Basal Borne at or near the base, as in placentation of ovules in an ovary or leaves arranged from the base.
Basal Plate This is a disk or reduced stem at the base of a bulb.
Basifixed Where the filament is attached to the base of an anther.
Basitonic Describing shoots from the lower part of the plant with the greatest development.
Beak A slender projection from the apex of certain fruit types.
Beard The arrangement of dense hairs in a line at the base of the outer perianth segments.
Being grass-like. Being grass-like.
Biennial Completing a life-cycle within two years, with flowering usually in the second year.
Bifid Forked, normally up to half way of its length.
Bimonthly Meaning both "twice a month" and "every two months
Bipinnatifid When a leaf is pinnately lobed and each lobe is equally divided.
Bisexual Having male and female reproductive organs on the same flower, inflorescence, or bract.
Biternate When a structure (leaf) is divided again into three segments.
Bivalved Having two valves.
Blind When a flower bud fails to develop into a flower.
Blossom A flower, normally referring to fruit trees.
Bole Describing the trunk of a tree.
Bough A main branch of a tree.
Bract (adj. Bracteate) Modified or reduced leaf subtending a flower or inflorescence in its axil.
Bracteole Small leaf-like organ situated on a stalk between a subtending bract and other organ.
Branchlet A twig or small branch.
Bristle A stiff hair.
Bud Undeveloped shoot, leaf, or flower with or without protective scales.
Bulb Underground compacted stem, surrounded by a number of swollen leaf bases or scales enclosing next year's bud, and functioning as a perennating device.
Bulbil Small bulb often arising on aerial organs (eg leaf axil or inflorescence).
Bullate With blister-like swellings on the surface
Bur, Burr A prickle on fruit that aids in dispersal of the seed by animals.
Buttress Root An adventitious root occurring at the base of a tree and connecting with the ground.
Caducous Falling off easily at an early stage.
Caespitose Tufted
Calcarate Spurred.
Calciphile A plant that prefers soils that contain lime.
Califlorous When the flowers and fruits grow on short stems from the trunks and large branches.
Callus The hardened and thickened tissue over a damaged area. Protective covering.
Calyptra This is a hood or lid-like structure on a bud, fruit and sporogonia.
Calyx (pl. Calyces) A part (floral receptacle) of the flower that is made up of the sterile sepals
Canaliculate Having a longitudinal groove.
Cane A hollow stem that is jointed and woody, as in bamboo.
Canescent Is when a surface is covered in tiny white hairs giving a whitish appearance.
Capillary Hair-like
Capitate Head shaped, in a dense cluster as in the flowers of the Asteraceae family.
Capitulum Condensed inflorescence, as found in daisies, composed of numerous stalkless flowers.
Capsule In angiosperms it is a dry dehiscent fruit that consists of two or more united carpels with an enclosed membrane. Loculicidal; splitting when mature midway between the partitions of the capsule. Septicidal; splitting at maturity along the partitions of the capsule. Septifragal; when the valves break away from the partitions.
Carbohydrate A compound based on carbon, hydrogen and oxygen, as in sugar or starch.
Carbon Dioxide (Co2) A gas that is colourless and odourless that is required for photosynthesis.
Carina (Keel) Two united petals in the lower part of a flower.
Carnivorous Plant capable of trapping and digesting insects.
Carnose (Carnous) With a fleshy or pulpy texture.
Carotens Red or orange pigments that occur in the chromoplast of cells, as in carrots.
Carpel Unit of the gynoecium containing one or more ovules.
Caryopsis Dry fruit of grasses.
Cataphylls A leaf that is modified to form other specialised functions such as a bud-scale or rhizome and a cotyledon.
Catkin The pendulous, bracteate (spike or raceme-like) inflorescence of usually unisexual flowers, falling as a unit.
Caudate Having a tail-like appendage.
Caudex A trunk or stem of a woody monocotyledon with slow incremental or long durational growth.
Caulifory When flowers are produced from the trunk or branches rather than the branchlet or twigs.
Cell This is the smallest unit of plant tissue that can function by its self.
Centripetal Developing from the margin towards the centre, normally referring to petals.
Cephalium Having a dense mass of hair at the top of a stem, as in some cacti species.
Cereal A grass that produces editable grain.
Chaff Describing thin, membranous bracts or scales normally found at the base of florets.
Chalaza The basal part of a nucellus of an ovule.
Chamaephyte Small woody or herbaceous perennial that has resting buds that are less than 25cm (10in) above the soil.
Chaparral Chaparral biome consists of mountains and plains similar to deserts but receives more rainfall per year.
Chartaceous Having a papery, colourless appearance.
Chasmophyte A plant that grows in rock crevices.
Chimaera A plant that has two different genetic types, as in a grafted plant.
Chiropterophily When pollinated by bats.
Chlorophyll Green photosynthetic pigment.
Chlorosis Deficiency of chlorophyll, causing plants to become unhealthy with green areas turning yellow.
Chromosomes Small bodies visible when suitable stained at certain stages of cell development, the bodies carrying most of the inherited characters of organisms.
Cincinnus An inflorescence that is cylindrical with the axis on different planes and branching alternately to one side then the other. (spiral cyme)
Circinate Coiled in a flat spiral as in a developing fern frond.
Cirrhiferous Having tendrils.
Clad When plants are derived from a common ancestor.
Cladode (phylloclade) Shoot or stem that takes the form and functions as a leaf.
Class A taxonomic rank between division and order and ending with -opsida.
Clavate Club-shaped.
Clavate A bud shape that is slender conical with a pointed or rounded apex.
Claw Narrow lower part of some petals and sepals.
Cleft When the apex is deeply divided into two lobes.
Cleistogamy (adj. Cleistogamous) Self-pollination mechanism taking place in unopened flowers.
Climber A plant that grows upward by using tendrils or twinning as a support on other plants.
Cline A gradual variation of one or more character within a species.
Clone A group of plants that have produced vegetatively and are genetically identical.
Coalescent Grown together.
Cob A woody stem with grains attached.
Coccus (pl. Cocci) Part of a fruit which splits into one-seeded portions.
Coenocarpium When a fruit is produced from an entire inflorescence as in Ficus species.
Coherent Simular parts that are in close contact with each other but not fused.
Coleoptera (Beetles) These insects have chewing mouthparts and a complete metamorphosis. They have two pairs of wings in which the forewings are covering the hindwings when at rest. The larvae are grubs or wireworms.
Coleoptile A protective sheath that surrounds the plumule in grasses as it grows through the soil.
Colpate Possession of colpi (of pollen) or pollen-wall apertures.
Column The combined style and stigma organ seen in orchid flowers.
Coma The tuft of hair that appears at the end of some seeds or the apical crown of leaves on the pineapple fruit.
Comose Having a tuft of hairs.
Compatible When two plants can fertilise each other.
Compound Consisting of several similar parts.
Compressed Flattened
Concave Having a hollowed out appearance.
Concolorous When both surfaces of a leaf are of equal colour intensity.
Conduplicate Folded together lengthwise.
Conifer A plant that produces cones.
Connate Similar organs joined or attached to each other.
Connective Tissue connecting together the pollen chambers of an anther.
Connivent Parts coming into contact or converging.
Contorted Sepals or petals twisted together in one direction in bud.
Convex A surface that is rounded.
Convolute Rolled together.
Coppice Shoot A shoot that develops from a dormant bud of a trunk after the trunk has been reduced to a stump.
Coriaceous Leathery.
Corm A bulb-like structure, formed from a large underground stem base, and stores food. Protective dry scales may contain cormels or offsets.
Cormel (Cormlet) A small corm.
Corolla This is the collection of petals that make up the flower.
Corona Ring of appendages, or ring-like appendage on the inside of the petals or perianth.
Cortex (plural Cortices) The tissue in a stem or root between the epidermis and the vascular tissue on the outer part of the plant.
Corticate Having bark.
Corymb (adj. Corymbose) Flat-topped inflorescence of racemose sort, the upper flower stalks becoming shorter so that all the flowers tend to occur at the same level.
Costa (pl. Costae) A rib or a prominent ridge.
Costapalmate A simple leaf with segments to half its depth that have ribs or strong ridges running longitudinally and forming a circular outline.
Costate Ribbed.
Cotyledon First leaf-like organ(s) of a plant either remaining within the seed coat (in hypogeal germination) or raised above the ground (in epigeal germination).
Creeper A plant that grows across the ground, up walls or over fences.
Cremocarp A dry fruit that has two one seeded carpels that separates on maturity into mericarps, as in Umbelliferae family.
Crest Toothed or irregular edge on the upper part of an organ.
Crossing The term used for the process of cross-fertilisation.
Crown In a tree it is the part above the first branches and in turf it is compressed stem where the leaves, roots, tillers and stems emerge.
Crozier This is the coiled young frond of ferns.
Cruciform (Cruciate) When in the form of a cross.
Cryptogam Having the capability to remain dormant for a long period in the absence of water.
Cryptophyte A plant with resting buds, that is either beneath the ground as in a rhizome or bulb, or under water.
Cucullate Hood-shape.
Culm Stalk of grass or sedge.
Cultigen A plant that has been cultivated and hybridised so extensively that the wild origins are uncertain or lost.
Cultivar A cultivated variety that may not be attached to a particular species, but has been selected for a particular attribute or attributes.
Cupule Cup-shaped sheath or bract surrounding some fruits.
Cuticle A waxy layer of cutin, covering the outer surface of the epidermis restricting the movement of water and gases in and out of a plant.
Cyathium A leaf that is modified to form other specialised functions such as a bud-scale or rhizome and a cotyledon.
Cyathophylls The bract-like structure of a euphorbia on which the involucre sits, usually but not always occurring in twos
Cylindric (cylindrical) With the shape of a straight tube but is solid.
Cyme (adj. Cymose) Inflorescence with tip terminated by a flower, so further flowers arise from new lateral growth, and the central or terminal flowers opening first.
Cypsela Small, single-seeded indehiscent fruit, as seen in daisies and an achene fruit derived from an inferior ovary.
Cyst A bladder or sack containing a liquid secretion.
Cystolith Crystalline inclusion(s) within cell, visible in leaves of certain plants.
Cystolith This is a rounded stone-like mass like calcium carbonate that appears in the epidermal cells in some plant species.
Cytoplasm The protoplasm of a plant cell excluding the nucleus.
Deciduous Seasonal shedding of leaves in perennial plants.
Declinate Downward curvature of the stamens of a flower.
Decumbent A shoot that is mainly prostrate turning upwards and ascending towards the tip.
Decurrent As when a leaf blade extends past its place of insertion giving the stem a ribbed appearance.
Decussate Arrangement of organs in opposite pairs at right angles to each other successively, at regular intervals, at different heights on an axis, as in leaves on a stem.
Deflexed Abruptly bent downwards.
Dehiscent Opening or splitting, with the purpose of shedding pollen or seed.
Deltoid Triangular shape.
Dendriform Tree-like.
Dendritic Hairs that are branched like a tree.
Dendrology The study of trees.
Depauperate Poor conditions lacking essential elements for growth.
Dermal The outer covering of an organ.
Diatropism The growth of a plant at right angles to the growth source, as in a horizontal rhizome.
Dichasial (cyme) A cyme having two lateral flowers or branches originating from opposite points beneath a terminal flower.
Dichotomously Dichotomously branched is when the terminal bud divides forming two equal branches that are not derived from axillary buds.
Dichotomy When divided into two parts.
Dicotyledon A plant, the embryo of which has two cotyledons.
Digitate When arranged like the fingers on a hand.
Dilated Become broad or enlarged.
Dimorphism (adj. Dimorphic) Having two forms, such as in the life cycle of ferns.
Dioecious Male and female flowers borne on separate plants.
Diploid When a cell containing two sets of chromosomes.
Diptera (Flies) The larvae of this insect, which are maggots, have chewing mouthparts and the adults have piercing and or sucking mouthparts. They have a complete metamorphosis and one pair of wings.
Dipterous Having two wings.
Disc Floret A single regular flower, from the centre of a flower head, normally in the Compositae family.
Discolorous Varying or different colours.
Disjunct Having a widely separated disontinuous geographical distribution.
Disk Fleshy or nectar-secreting part of the receptacle surrounding, or on top of the ovary. Also the reduced stem at the base of a bulb or the name referring to the central part of a capitulum.
Dispersal The scattering of seeds away from the parent plant.
Dissected Divided into segments.
Distichous When leaves are arranged in 2-ranks, opposite sides of the stem and on the same plane.
Diurnal Occurring during daylight.
Divaricate When forked or widely divergent.
Divergent When plants spread away from each other.
Domatia Small projections, often on leaves.
Dormancy The lack of growth in any plant part as a result of internally or external induced factors.
Dormant seed A seed that fail to germinate though the embryo is alive and has absorbed water in favourable environmental conditions.
Dorsifixed Where the filament is attached to the back of an anther.
Double Flower A flower with additional petals to the typical form.
Drip Tip This is a long pointed apex that aids in the rapid shedding of water from the leaf surface.
Droppler A downward growing shoot from a bulb, producing a bulb at its apex.
Drupe The inevitable results of imbibing excessive quantities of cheap plonk. Or, a fleshy fruit with one or more seeds surrounded by a hard or stony layer (eg cherry).
Dwarf A variety of plant that is much smaller than the average in a species.
Ear A description of an inflorescence in a cereal grass.
Echinate Having spines which are not sharp.
Ecology This is the study of plants and animals and there interaction with the environment.
Elaiosome Fleshy, oily outgrowth of seed attractive to ants.
Ellipse A flattened circle shape.
Ellipsoid A three dimensional elliptical shape.
Emarginate Notched at the tip.
Embryo Rudimentary plant contained within the seed.
Emulsion When the droplets of one fluid are suspended in another such as in oil and water.
Endemism (adj. Endemic) Restricted geographically location to a single area, place, region or country.
Endocarp Innermost layer of the fruit wall; often becomes hard and stony in drupes.
Endogenous Developing within the plant.
Endophyte When a plant lives inside another plant.
Endosperm Nutritive tissue or food reserve surrounding the embryo in some seeds of flowering plants.
Endozoic Editable fruits that are dispersed by animals, normally in its waste material.
Entomophily When a flower is pollinated by insects.
Environment All external influence acting on a plant.
Enzyme A protein produced by a cell that is a catalyst for a biochemical reaction.
Epharmonic Modification in a form for a specific ecologic condition.
Ephemeral When lasting for a short period of time.
Epicalyx Whorl of sepal-like appendages outside the true calyx.
Epicarp (exocarp) The outer layer of the pericarp.
Epichile This is the apical portion of the labellum found in an orchid.
Epicormic Shoots that occur from large branches or from the side of a trunk.
Epidermis (adj. Epidermal) Outermost layer of living cells affording a protective cover to herbaceous plant organs.
Epigeal When the seed coat is carried to the surface of the soil by the cotyledons.
Epigynous Having stamens and perianth inserted on top of the ovary.
Epipetalous Attached to the petals or corolla.
Epiphyte This is an independent plant that requires another plant for support, with no soil and some superficial nutrients from decaying matter.
Epiphyte (adj. Epiphytic) Plant growing on the surface of another, without deriving nourishment from its support as a parasite does.
Episepalous Attached to the sepals or calyx.
Epithelium Secretory cells that line internal cavities in plants, producing gum or resin.
Epizoic When seeds are dispersed by animals fur using hooks or barbs.
Erect Upright, with its stalk at the base (of ovules).
Escape When a plant has established its self out side the defined garden.
Espalier A method of pruning and tying branches to a frame or against a wall.
Etiolated (Adj. Etiolation) When a plant is weak or pale in colour, drawn out with a long internodal spacing from the lack of light.
Evergreen A plant that retains its leaves throughout the year.
Exfoliation (Adj. Exfoliating) It is the process of shedding bark in plates, layers or flakes.
Exindusiate Without an indusium
Exine Outer layer of pollen grain wall.
Exocarp Outermost layer of the fruit wall.
Exotic A plant that is not native to the area and originated from another country.
Exserted Sticking out from surrounding parts.
Exstipulate Without stipules.
Extrorse Opening away from the central axis of the flowers (of anthers).
Eye Eye Botanically it describes the pits on a potato tuber, the roundish areas on the base of a coconut or indicates the position where a shoot will emerge, from a germinating seed.
F1 The first resulting hybrid from a cross of two different parent plants.
F2 The second generation resulting from F1 crosses.
Fall Describing the outermost perianth segments of certain flowers, i.e. Iris. Also a description of autumn, (when leaves fall).
Family Group of genera resembling each other by a combination of characteristics more closely than they resemble other groups and, in plants, given a Latin name, usually based on one of the genera, with the family suffix ~ae or ~aceae (eg Palmae, Ericaceae, etc).
Farinose When covered in fine powder.
Fasciation When a stem has a flattened appearance as if several stems are placed side to side. Caused by meristem damage resulting from bacteria or mutation, i.e. the flower of Celosia cristate is a mutation.
Fascicle Bundle.
Felted When densely matted with intertwined hairs.
Female Containing functional gynoecium but no stamens, or only their rudiments (of flowers).
Fenestration This is a translucent area found in a leaf or flower.
Fern A plant that is in the Filicopsida class and having large fronds.
Fern Ally A plant in the class of Psilotopsida (forked ferns) or Lycopsida (club mosses and quillworts) and Equisetopsida (horsetails).
Fertilisation Fusion of male and female reproductive cells in the ovule after pollination.
Fibres Cells that are elongated and pointed at both ends. (thread-like)
Filament The supporting thread-like structure of the anther in the flower.
Filament Anther stalk.
Filiform Thread-like.
Fimbriate Fringed (of edges).
Firfuraceous Scaly or scurfy.
Fissure Normally a narrow opening caused by the separation of organs.
Flabellate Fan-like.
Flaccid Having a withered or limp appearance.
Floccose Having small tufts of hairs.
Flora The plants that grow in a particular region.
Floral Diagram A detailed cross section drawing of a flower, showing the position of all parts.
Floret Generally a very small flower and in grasses an individual flower that is enclosed by a lemma and a palea.
Floriferous Having numerous flowers.
Flower Reproductive structure comprising calyx, corolla, androecium, and gynoecium found in angiosperms.
Foetid (Fetid) Pungent, with a highly unpleasant smell.
Foliage Relating to all the leaves of a plant.
Foliose Leafy
Forb Herbaceous plants other than a grass.
Form A description of a slight variation in a plant, i.e. flower colour.
Free Unfused.
Frond It is a combination of a leaf and stem (not leaves).
Fructification The production of fruit in flowering plants or the spore bearing structures of a fern.
Fruit Structure containing the seeds and comprising the ripened ovary, or also parts of the receptacle.
Fruticose Shrubby habit.
Funicle Ovule stalk.
Fused Completely united.
Galea A hood structure that is composed of the perianth segments of a flower.
Gamete A male or female sex cell that unites at fertilisation to form a zygote.
Gametophyte When plants cells are reduced by half during the sex stage of the life cycle, normally diploid is reduced to haploid.
Gamophyllous When a flower has petals and sepals that are united.
Geminate When arranged in pairs.
Gemma When a plantlet develops from adventitious bud on a fern frond.
Gene A fixed unit on a chromosome that by its self or with other units determines such things as flower colour, hight or any of the characteristics of a plant.
Genet The production of one or more individuals from the asexual reproduction of a single zygote.
Genus (pl. Genera) Group of species resembling each other by a combination of characteristics more closely than they resemble other groups, and the generic name forming the first part of the two-word species name (eg Ficus, Santalum, etc).
Geocarpy Fruits that ripen below the ground with the flowers born above the ground.
Geophyte A herbaceous plant that perennates by using underground buds as in bulbs, corms and tubers.
Germination This is the process of reactivation of the metabolic machinery of the seed. The emergence of the root and shoot.
Gibbose Having a pouch-like swelling.
Girdle Scar A scar that is left from the previous years terminal bud.
Glabrous Without hairs or other large projections.
Gland (adj. Glandular) Organ secreting oil, resin, nectar or water.
Glaucous Bluish cast produced by waxy substance on organs.
Globose Spherical or rounded.
Glochidium Having barbed hair or bristles.
Glume A state of unhappiness. Or, a pair of bracts present at the base of a spikelet as in grasses and sedges.
Glutinous Sticky.
Graft Joining of living parts of differant origins to form a single plant.
Graminoid Grass-like.
Gregarious Growing in open clusters.
Guard Cell A pair of cells in the stoma that control the size of the aperture, and regulate the flow of gases in and out of the plant.
Guttation Secretion of water droplets from the leaf apex or margin from the hydathodes.
Gymnosperm A seed bearing vascular plant that normally produces cone structures.
Gynobasic Arising near the base of a deeply lobed ovary (of styles).
Gynoecium The female parts of a flower; unfused carpels or an ovary of fused carpels.
Gynophore Gynoecium stalk.
Habit The form and shape of growth of a plant.
Habitat The location where a plant lives and is governed by soil type, moisture, temperature and other environmental conditions.
Halophyte A plant that has adapted to tolerate saline conditions.
Hamate Hooked.
Haploid When a cell has half the number of chromosomes.
Haplostele A central core of xylem surrounded by a ring of phloem.
Hardiness The ability of a plant to withstand unfavourable conditions, normally relating to cold temperature.
Hartwood (Duramen) The older inner layers of wood in the trunk of a tree.
Hastate Halberd (or pole-axe)-shaped.
Hastula Tissue that forms a flap and is found at the junction of the petiole and lamina of some palm species.
Haustorium Fleshy outgrowth attaching a parasitic plant to its host.
Head Description of a dense inflorescence as in the capitulum in the Compositae.
Heel Is a small piece of tissue that is torn from the stem when a cutting is taken.
Helices (pl. helix) The curve formed by a straight line drawn on a plane when that plane is wrapped around a cylindrical surface.
Heliophyte When a plant adapts to living under high light intensities.
Heliotropic When a plant turns towards the light.
Helophyte A plant that grows in a marsh with its resting buds below the surface.
Hemi-parasite (Half-parasite) When a plant derives some of its nourishment from a host.
Hemiptera (True Bugs)- These insects have piercing and sucking mouthparts with an incomplete metamorphosis. They have two pairs of wings with the forewings thicker at the base and covering the hindwings at rest.
Herb (adj. Herbaceous) The old bloke who lives next-door. Also, any non-woody plant excluding mosses and algae, or a general name for medicinal or culinary plants (which are not always non-woody).
Herbaceous Perennial A herb that shoots partially or wholly dies back at the end of the growing period and re-shoots after a period of dormancy.
Hermaphrodite Having functional male and female organs in the same flower, or on the same plant.
Heterostyly (adj. Heterostylous) Having styles and stamens of different lengths in flowers on different individuals of the same species.
Hetrophyllous When a plant has more than one type of leaf.
Hibernaculum A winter bud that the plant regenerates from, after dying down.
Hibernal Occurring during winter.
Hip This is the false fruit in the genus Rosa, forming a fleshy hollow containing achenes.
Hirsute When the surface is covered in coarse hairs.
Hispid When having stiff, bristly hairs.
Hoary When covered in small whitish hairs giving a frosted appearance.
Homogeneous When a structure is uniform, composed of simular or identical parts.
Homologous Having simular structure and origin.
Homoptera (Aphids, Mealy Bugs) These insects have piercing and sucking mouthparts and an incomplete metamorphosis. They have either two pairs of wings or none and both pairs of wings are the same. This includes Scales.
Hormone A substance that has a specific effect on the plants growth or development.
Hose-in-hose When a flower grows from within another flower, normally in pairs.
Host The plant that supplies the nutrients for a parasite.
Husk The outer covering of certain seeds, as in Zea mays, (sweet corn).
Hybrid Offspring resulting from fertilisation of a member of one sub-species, species or genus by a different member.
Hydrochory The dispersal of seeds by water.
Hydrophyte When pollination occurs by water.
Hydrophyte An aquatic plant, requiring waterlogged soils to grow in.
Hydrotropism When a plant grows towards water, normally roots seeking water.
Hymenoptera (Bees, Wasps, Ants) These insects have two pairs of similar wings and chewing mouthparts. Their metamorphosis is complete and the larvae are grubs. It includes Sawflies.
Hypanthium This is a floral cup or tube-like structure that is created from the fusion of calyx lobes. It is also fused to other floral parts including the stamens and petals at the apex.
Hypocotyl The part that gives rise to the roots below the cotyledons in a seedling.
Hypogeal When the cotyledons remain underground during germination.
Hypogynous Having stamens and perianth inserted around the base of the ovary.
Imbricate Overlapping organs, like tiles on a roof.
Imperfect Flower When a flower has only the androecium or the gynoecium functioning.
In Vitro Culture Under glass, study of plants under sterile conditions and away from the parent.
Incised A deep cut into narrow angular divisions.
Incompatible Unable to produce viable offspring.
Incurved Curved upwards, normally associated with leaf margins.
Indehiscent Not opening or splitting for the purpose of releasing seed or pollen.
Indumentum Hair covering.
Induplicate When folded inwards or upwards.
Indurate Hardened.
Indusium This is the membrane that covers the sorus.
Inferior ovary An ovary that is embedded in the pedicle with the perianth and stamens above.
Inflorescence Flowering part of a shoot comprising axes, flowers and bracts.
Inserted When growing out from another part of the plant.
Internode Portion of stem between two successive nodes.
Intrafloral Within the flower.
Intramarginal Close to or within the margins.
Introduced A plant that has its origin in another region.
Introrse Opening towards the central axis of the flower (of anthers).
Introrse When the anthers face inwards towards the centre of the flower.
Involucre One or more whorls of bracts at the base of the flower.
Involute When the leaf margins are rolled inwards on the upper surface of the leaf.
Irregular Not in regular symmetry.
Isomorphic With simular form.
Isthmus When an organ has a narrow part connecting two broader parts.
Jugate When joined together in pairs.
Juvenile Foliage Young leaves, normally different to adult foliage, as in some Eucalyptus species.
Keel A term to describe a ridge or sharp fold on the back of a sheath or blade in turfgrass.
Keiki A plantlet produced asexually by an orchid plant appearing from a node.
Kernel A cereal grass grain or an editable nut within a hard pericarp.
Key-out A method of sorting a plant into family, genus and species.
Kingdom A taxonomic rank including all plants with a number of divisions.
Knot This is the hard tissue formed where a branch grows from a trunk and is seen clearly in cross section.
Labellum A modified petal, a lip in the Orchidaceae family or a showy petaloid structure in Zingiberaceae and Costaceae family. It is a part of a flower the attracts insects and acts as a landing platform for pollination.
Lacerate Irregular cut or jagged.
Laciniate Split into narrow, slender lobes.
Lacuna A space or cavity.
Lamina Thin flat blade of a leaf or petal.
Lanate Woolly.
Lateral On the side.
Latex Milky juice characteristic of some plants.
Lax Not dense, loose and open.
Leaf Aerial, sterile appendages of the stem, together comprising the shoot system, the chief function being food manufacture by photosynthesis.
Leaf Apex The point at the top of a leaf, the apex.
Leaf Sheath When the lower part of a leaf stalk is encloses the stem.
Leaflet A separate piece of a compound leaf.
Legume Capsular fruit opening along one or two sutures in Leguminosae.
Lemma In a grass it is the lowermost scale of a floret.
Lenticel A space or pore that appears corky on the bark and allows for gaseous exchange from the inner tissues to the atmosphere.
Lepidoptera (Moths, Butterflies) The larvae of these insects are grubs or caterpillars and they have chewing mouthparts. The adults have sucking mouthparts, a complete metamorphosis and two pairs of similar wings.
Lepidote When covered in small fine scales.
Liana (Liane) A climber with woody stems and grows in rainforests from the ground to the tree canopy.
Life Cycle The development of a plant from a stage in its life through to that stage again.
Ligneous Woody.
Lignotuber A swelling growth at the base of the plant and maybe underground, containing dormant buds that shoot when top growth is lost.
Ligulate Strap-like, small tongue-like
Ligule Scale-like membrane on leaf surface, or strap-shaped corolla of some Compositae, or appendage on palm petiole.
Ligule (Costus) It is an extension of the leaf sheath that continues above the place where the petiole is joined to the sheath. The length is used as an identifier in the Costus species.
Lineate Marked with lines.
Lip One or two divisions of a bilabiate corolla.
Lithophyte A plant that grows on bare rock or rocks (substratum).
Littoral In relation to a seashore or lakeside region.
Loam A loose soil that is composed of clay and sand with organic matter and is fertile.
Lobe A division of an organ, normally rounded.
Locule Chamber.
Loculicidal Splitting open longitudinally along the mid-rib of each fruit segment wall.
Lustrous Glossy, smooth and shiny.
Lyrate Is a pinnate leaf with the terminal lobe being large and rounded with successive leaflets being rounded and smaller.
Macrophyll A term to describe larger leaves.
Macrophyte A plant that can be seen with the naked eye, especially an aquatic species.
Maculate Having spots or markings.
Male Containing functional androecium but no carpels or ovary, or only their rudiments (of flowers).
Malodorous Having a bad smell.
Massula When a single cell develops a cluster of pollen grains.
Mat In grasses this is the area between the top of the green vegetation and the soil. This includes living and dead stems, root material and top dressing soil.
Mealy Covered in flower-like, coarse powder.
Medial (Median) The middle.
Medulla Centre of an organ, as in the pith of a young stem.
Megaspore When a spore develops into a female gametophyte.
Membranous When thin and transparent.
Mericarp One-seeded piece of a fruit that splits apart when mature (eg Umbelliferae).
Meristem Tissue that undergoes cell division throughout the plants life and is found in the tips of shoots and roots, also in the cambium.
Mesic A habitat with a well balanced supply of moisture in the soil and organic matter.
Mesocarp The mid-layer of the fruit (between exocarp and endocarp).
Mesophyll The photosynthetic tissue inside a leaf.
Mesophyte A plant that grows and is adapted to moist positions.
Metamorphosis Changing from one structure to another, as in stamens to petals.
Microclimate The climatic conditions that occur in a small area or region.
Micronutrients (Trace Elements) Elements that are only required in small amounts for plant growth, such as, iron, manganese, boron, zinc, molybdenum, chlorine and copper.
Microsporangium Is a spore sack where the microspores are produced.
Microspore A spore that develops into a male gametophyte.
Microsporophyll A leaflike structure that bears microsporangia such as a the male cones of conifers and corresponds to the stamen of a flowering plant.
Midrib The middle and main vein of a leaf.
Moniliform A cylindrical structure that has constrictions at regular intervals. Looks like a chain of beads.
Monocarpic Flowering and fruiting once before dying.
Monocotyledon A plant, the embryo of which has one cotyledon.
Monoecious Male and female flowers borne on the same plant.
Monopodial Branches arising from a single main axis.
Monospecific A genus containing only one species.
Monotypic Genus or family comprising of a single species.
Montane When growing in mountainous regions.
Morphology The study of a plants form.
Mucro A short, sharp tip.
Muricate Roughness caused by tiny excrescences.
Mutant A sport, an individual plant that has occurred from a mutation.
Mycorrhiza Symbiotic fungi associated with the roots of certain seed plants.
Myrmecochory Seed dispersal by ants.
Naked Lacking perianth (of flowers).
Nastic Movement Independent movement of a plant, such as opening or closing flowers in response to temperature or light.
Natant Floating in water.
Naturalised Established after being introduced from another region.
Necrosis Localised dead tissue surrounded by live tissue.
Nectar Sugary secretion from the flowers of some plants.
Nectary Gland from which nectar is secreted.
Needle A narrow leaf description, as in conifers.
Neotropical A zoogeographical region that includes Central and South America, tropical Mexico and the Caribbean.
Net-veined Veins that are joined forming a network across the leaf.
Neutral Soils Soils with a pH of 7.
Nitrogen Fixation A bacterial process converting gaseous nitrogen into compounds that are used by plants.
Nocturnal Occurring at night.
Node Part of the stem which bears a leaf or bract.
Nodule A rounded growth on plant roots that contains nitrogen-fixing bacteria.
Nose The pointed end of a bulb.
Nuciferous Bearing nuts.
Nut (dim. nutlet) Simple, dry indehiscent one-seeded fruit with woody pericarp.
Nutrient A substance required for plant growth.
Obligate A plant which is unable to grow on its own without recourse to parasitism, saprophytism, or carnivory.
Obvolute When one leaf half raps around another leaf when in bud.
Ochrea Cup-shaped or tubular sheath formed from joined stipules above a node.
Odorous With a distinct smell.
Offset (Offshoot) A runner that produces a new plant from the parent.
Oleiferous Producing oil.
Ombrophytic A plant that grows in rainy habitats.
Operculum A shedding cover or cap of a flower.
Opposite Arrangement of organs in pairs adjacent to each other successively at regular intervals on an axis.
Orbiculate More or less circular in outline.
Order A taxonomic rank composed of a group of families, ending with ‘-ales’
Ornithophily Pollination by birds.
Orthoptera (Grasshoppers Locusts) This insect has chewing mouthparts and two pairs of wings with the thicker forewings covering the hindwings when at rest. They have an incomplete metamorphosis and their hindlegs are modified for jumping.
Orthotropic When growing directly towards the source of the stimulus.
Osmosis When molecules of a solution of low concentration move to one of high constriction through a membrane that is semi-permeable until they are balanced.
Outgrowth A structure that grows out from the main body.
Ovary Fusion together of more than one carpel into a protective structure enclosing the ovules and surmounted by a style (or styles) and stigma(s).
Ovule Structure containing the egg-cell, developing in to a seed after fertilisation and situated in the carpels or ovary.
Pachycaulous A plant with a disproportionately thick trunk for its height, and has few branches.
Palea Generally it is a bract that has a thin and stiff texture and in grass it is the upper scale of a floret partially enclosed by the lemma.
Pannose When densely matted with woolly hairs, felty.
Papillose Having tiny, pimple-like projections.
Pappus Compositae fruit that forms a feathering or tufted bristles.
Parasite Organism deriving its food from another living organism, via a physical attachment.
Parenchyma Soft tissue consisting of thin walled cells and often having spacing, as in pulp of fruit.
Parietal Type of placentation of ovules situated on the inner surface of the outer wall of the ovary.
Pathogen This is an organism that causes disease.
Pectinate Comb-like
Pedate A palmate leaf with the primary leaflets are again divided (foot-shape).
Pedicel A stalk of a single flower.
Peduncle The stalk of an inflorescence.
Pellucid Being transparent, clear
Peltate The leaf-stalk (petiole) inserted through the leaf blade.
Pendent (Pendulous, Pensile) Hanging downwards.
Pepo A hard-walled berry with many seeds, as found in the family Curcurbitaceae.
Perennate To live for many years like a perennial.
Perennial Living longer than two years, usually flowering each year.
Perfect Functional male and female organs present (of flowers).
Perfect Flower A flower with functioning androecium and gynoecium.
Perianth The sterile floral organs comprising sepals and petals or, where indistinguishable, the tepals as in lilies.
Pericarp Fruit wall developing from the ovary wall to encase the seed.
Periderm This is a secondary protective layer replacing epidermis in older stems and roots, normally corky.
Perigynous Having stamens and perianth inserted around (and at the same level as) the ovary.
Perisperm A nutritive tissue that is an accessory to endosperm of a seed.
Peristome The slippery rim of a pitcher in a carnivorous plant or an anatomical feature that surrounds an opening to an organ.
Perular Scale A basial scale that persists after the development of the shoot.
Petal Sterile member of the inner perianth series between sepals and stamens; often coloured.
Petaloid Petal-like.
Petiolate Having a leaf stalk (petiole)
Petiole It is the supporting part that joins the base of a leaf to the branch. It may vary from a simple straight petiole to swollen, winged, or sheathing.
Petrophilous Plants adapted to a rocky environment.
pH The value of hydrogen-ion concentration, with a scale from 1 (extreme acid) to 15 (extreme alkaline).
Phloem This is the vascular tissue that carries sap, which contains nutrients from the leaves to the other parts of the plant.
Photoperiodism A plants response to day or night, normally relating to flower development.
Photosynthesis Process of manufacture of sugars from sunlight, water and carbon dioxide, based on the conversion of solar energy into chemical energy, via the agency of chlorophyll.
Phylloclade Is a flattened branch or stem-joint resembling and functioning as a leaf.
Phyllode Is a petiole that functions as an entire leaf.
Phyllopodium An outgrowth on the rhizome of a fern that produces fronds.
Phylogeny Plants relationship determined by evolutionary history.
Pigment The natural colouring in plant tissue.
Pilose Having soft hairs.
Pinna (pl. Pinnae) The primary leaflets in a compound leaf.
Pinnatifid A leaf that is becoming pinnate with the divisions reaching one third to half way to the mid rib.
Pinnule A secondary or tertiary leaflet of a bipinnate leaf.
Pistil (adj. Pistillate) The gynoecium of a flower. Pistillate, referring to a female flower when the only fertile parts are carpels. The pistil includes the ovary, style and stigma when present.
Pistillate A flower where the fertile parts are carpels.
Placenta That part of the ovary-wall vascular system to which the ovules are attached.
Placentation The pattern of arrangement of placentas in the ovary.
Plica A fold.
Plicate Folded together, as in a fan.
Plumose Feathery.
Plumule Rudimentary shoot in the embryo of a seed.
Pneumatophore A special stem-like root for gaseous exchange in poorly aerated soils normally found in mangroves.
Pollarding Is a method of changing a tall but sparsely foliage tree by pruning at a given level to produce pollard-shoots and encourage a denser crown.
Pollen The male's spores produced in the anthers.
Pollination The transfer, by various means, of pollen grains from stamen to stigma.
Pollinium (pl. Pollinia) Coherent pollen mass found in orchid flowers and transferred, as a unit, during pollination.
Polyandrous Having many stamens.
Polygamodioecious With male and bisexual flowers on one plant, and female and bisexual flowers on others.
Polygamous With separate male, female and bisexual flowers on the same plant.
Polygynous Having many styles.
Polymorphic Variation of the appearance within a species in different forms.
Polypetalous Having distinct free petals.
Polyploid Having more than the normal two sets of chromosomes in each cell.
Polystichous When arranged in several or many rows.
Polytelic When the inflorescence branches end with no flowers.
Pore A small aperture that is normally rounded.
Precocious Flower One that opens early in the season before the leaves develop in deciduous plants.
Prickle A sharp outgrowth from a stem, as in Rosa species.
Procumbent Laying flat on the ground with out rooting.
Profile A vertical exposure of soils from the surface to the underlining unweathered material.
Progeny Immediate descendent, as in a offspring.
Prolepsis When a bud forms a lateral shoot after dormancy.
Proliferating When buds are produced in the axils of the perianth segments.
Prop Root (Stilt Root) An adventitious root that grows from the lower stem or branch to the soil for support.
Propagation The multiplication of plants by means of, seed, cuttings, division or under sterile conditions as in Vitro culture.
Prophyll Bracteole.
Prothallus When a plant develops from a spore and lacks roots, stem or true leaves, but has male and/or female sex organs.
Protogynous Receptiveness of stigmas before stamens release pollen.
Protoplasm This is the living material within the plant cell.
Provernal Occurring during early spring.
Pruinose With a bloom.
Pseudanthia A special type of inflorescence that can contain hundreds of flowers. (Greek: false flower)
Pseudobulb This is a thickened upright stem (false bulb which stores food and water).
Ptyxis The way a single leaf is folded up in a bud.
Pubescent Covered in short straight hairs that may be downy.
Pullulate To sprout, germinate or bud.
Pulse Editable seeds in the family Leguminosae, as in beans, peas and lentils.
Pulvinate Cushion-like.
Punctate When marked in dots, depressions or translucent glands.
Pungent Ending in a sharp point.
Pyrenes Nutlets in a drupe.
Rachillae A small or secondary rachis as in a spiklet or a palm inflorescence
Rachis (pl. rachides) The axis of a compound leaf or an inflorescence.
Radical When leaves arise directly from the rootstock.
Radicant Rooting.
Rambler A plant that climbs over adjacent plants, walls or fences.
Ramose Having many branches.
Ray It is the outer modified florets or some composites, when the corolla has an extended strap-like part. It is also referred to the branches of umbles.
Ray Floret One of the outer flowers in a flower head, normally in Compositae family.
Recurved Curved backwards, commonly associated to leaf margins.
Reflexed When bent abruptly backwards.
Refracted When a leaf margin is sharply bent down enclosing some of the underside.
Remontant A plant that blooms more than once in a season.
Repent (Reptant) When a plant creeps along the ground.
Resin A sticky insoluble substance that may be fragrant secreted by special cells in conifers.
Resupinate Turned completely around as to appear upside down.
Reticulate When marked with a network pattern.
Retuse Having a slight notch at the apex.
Revolute Referring to a lamina when the margin rolls back underneath towards the mid-rib.
Rhachi A spine.
Rheophyte Is an aquatic plant that lives in fast moving water.
Rhipidium A cyme in a fan-shape that has axes only on one plane that is branching alternately from one side to the other.
Rhizomatous A plant that forms a rhizome.
Rhizome Horizontal shoot that is subterranean or prostrate, with adventitious roots and buds. Ferns have short, medium and long creeping rhizomes.
Riparian When growing on the banks or streams.
Root A lower part of a plant that absorbs nutrients and may be branched, also anchors the plant to the ground.
Rootstock The basal persistent part of the stem of erect herbaceous perennials where the new shoots and roots arise in the next growing season. Also the root used as stock in propagation.
Rostellum Forming a beak.
Rostrate Forming a beak
Rubiginous With a rusty colour.
Ruderal A plant that grows in waste places.
Rugose (Rugulose) diminutive Having a wrinkled surface.
Ruminate Having a chewed appearance or with irregular depressions.
Runner Having a creeping stem across the ground and produces new plants at the nodes.
Sap The fluid of a plant.
Saprophytic Living on dead and decaying organic material.
Sapwood The younger layers of wood with cells that still conduct sap.
Sarcotesta A fleshy seed coat.
Scabrous A rough surface caused by minute protuberances.
Scale This is a dry, papery structure that is born on different parts of a fern.
Scandent Climbing as in the use of tendrils.
Scape The floral stem or peduncle of a stemless plant.
Scarification Physical or chemical means of breaking the dormancy of a seed and allow the penetration of water through the seed coat.
Schizocarpic A fruit that is dried and formed from multiple carpels that split and each carpel contains one seed. Not normally dehiscent.
Sclerophyll When a leaf is tough and leathery, normally associated with plants in a warm dry climate.
Scrambler A climbing plant with weak stems that sprawls over other plants or walls.
Secretion When a fluid is produced from a gland and released.
Sedge Any rush-like or grass-like plant that grows in wet places.
Seed It is a ripened ovule that consists of an embryo with its stored food supply and a protective covering.
Sepal The leaf-like unit of a calyx.
Septate Divided by partitions, (septa)
Septum A partition as in the walls that separate the loculi in an ovary.
Serotinal When occurring during late summer.
Sessile A flower, leaf or plant structure with no supporting part, example; a leaf with no petiole.
Seta A bristle.
Setose When a surface is covered in bristle-like hair.
Sheath A tubular covering.
Sicon A shoot that is inserted into a rootstock for grafting.
Siliqua A capsular fruit from a bicarpellate ovary dehiscent from the base, normally with two valves.
Siliqua A flattened siliqua.
Sinus A recess between two teeth or lobes along a leaf margin.
Siphonostele When the vascula arrangement (stele) forms a hollow tube that has parenchyma in side.
Sorus The fertile part of the frond (collection of sporangia).
Spadix (pl. spadices) An inflorescence, fleshy spike normally with embedded flowers.
Spathe A bract or leaf that encloses the bud stage of a leaf.
Spicate A spike-like structure.
Spicula A secondary spike or needle-like growth.
Spikelet In grasses the inflorescence subtended with a pair of bracts (glumes) with up to five florets. The spikelet may be a Raceme, Spike or Panicle.
Spine An outgrowth that is sharp and woody and may represent an entire leaf.
Spinulose Having small spines.
Sporangium It is a celled structure where the spores are produced.
Spore This is the reproductive unit in a fern.
Sporophyll A leaf or leaf-type that's bearing a sporangium.
Sporophylls Cone scales arranged around a central axis.
Sport Modified version of a plant but not a different species.
Spur A slender projection from a plant or a short leafy branch of a tree, sometimes with clusters of flowers.
Squamose When covered in large coarse scales.
Staminode A sterile stamen-like floral part, like a transition to a petal or a basic stamen.
Stele The primary arrangement of the vascular system.
Stipe This is the leaf petiole (supporting structure) from the rhizome to lamina or from the trunk to the frond.
Stipule Normally a pair of small growths at the union of the twig and petiole of the leaf and commonly falls off as the leaf matures leaving scars.
Stock A rooted stem in which a scion is inserted when grafting.
Stolon A shoot directed towards the ground and developing adventitious roots (natural layering).
Stoma (plural Stomata) A small pore on the underside of leaves that allows gases to pass out of the plant.
Stratification The need to bring a ripe seed out of dormancy by chilling under moist conditions for a period of time. (Depending on the seed)
Striate Having lines, channels or numerous fine parrallel veins with the margin.
Strigose Having stiff hairs or bristles.
Strobilus A structure for reproduction, as in a cone (of conifers)
Style Connects the stigma to the ovary with a sterile filamentous growth through which the pollen tube forms.
Suberin A fatty substance found in cell walls rendering them waterproof and resistant to rot.
Suberose Corky
Subshrub (Suffrutex, Undershrub) A low or small shrub tending to have herbaceous stems.
Subulate When tapering from the base to the apex, awl-shape.
Succulent Having a fleshy and juicy texture.
Sucker A shoot that emerges from the soil close to the parent plant.
Sulcate Describing a surface that is grooved or furrowed.
Superior ovary Above, normally relating to an ovary that is situated above the other floral parts on the receptacle. Hypogynous; with sepals, petals and stamens attached to the receptacle below the ovary. Perigynous; with sepals, petals and stamens arranged around the ovary on an extension of the receptacle (hypanthium).
Symbiosis When two organisms co-exist.
Sympodial Having a branching system.
Syn. An abbreviation for synonym (another name).
Syncarp A fruit type that consists of multiple carpels that is fused to the receptacle.
Tannin An acidic soluble substance with a bitter taste and having astringent properties.
Taproot A large, strong downward root that has smaller lateral roots.
Tassel A male panicle inflorescence.
Taxonomy A type of botany that deals with identification, classification and nomenclature of plants.
Temperate Zone A part of the earth's surface that is located between the tropics and the polar circles. It is a variable zone consisting of cool, warm and subtropical climates.
Tendril A thread-like appendage, which, by coiling around objects, enables plants to climb.
Tepal A perianth segment not clearly identifiable as a petal or sepal.
Terete A circular cross-section.
Terminal Situated at the tip and limiting further growth.
Ternate Compound in three approximately equal parts.
Terrestrial Meaning earth, a plant that grows in the earth.
Tessellated Having chequered markings in square patterns.
Testa Outer protective covering of the seed.
Thatch In grasses this is the layer of undecomposed to decomposed organic matter above the soil.
Thsanoptera (Thrips) These minute insects have an incomplete metamorphosis, they have chewing mouthparts and two pairs of identical wings.
Thyrse An inflorescence whose main axis is indeterminate, and whose secondary axes are cymose.
Tiller A Tiller is an above ground branch that develops from a bud on the stem of a grass plant.
Tomentose Covered with matted hair.
Torose Cylindrical swellings or restrictions at regular intervals.
Translocation The transfer of dissolved substances within the phloem and xylem of the plant.
Transpiration When water vapour is loss into the atmosphere through the stomata.
Trimorphic Occurring in three forms.
Tristichous Arranged in three especially vertical rows
Truss It is a cluster of flowers or fruit that grow on a single stem.
Tube A fused portion of the corolla or calyx.
Tuber (adj. Tuberous) A swollen piece of storage tissue of a stem or root, of one year's duration, that doesn't give rise to new tubers.
Tubercle (Podarium) A little tuberous or warty excrescence. A large modified leaf base or petiole where the leaf no longer exists and is fused to the stem tissues (Podarium). Common in cacti.
Tuft This term describes a loose, compact or dense cluster of vegetative shoots or stems also a small clump of bushes and trees.
Tunic The outer covering of a bulb or corm that is dry and papery.
Tunicate A structure that is surrounded by a membrane or tissue.
Turgid Cells that are, stiff or swollen from the uptake of water.
Tussock Forming a tuft or clump, normally relating to grasses.
Typical Insect. This is a simplified diagram of the external structure.