Glossary

-merous: Having a specified number of parts. In plants usually refers to floral parts: so a ‘5-merous’ flower has five sepals five petals five (or ten) stamens etc.
abaxial: (especially of surface of a leaf) Lower; facing away from the axis. (Cf. adaxial.)
abscission: Shedding of a part of a plant (e.g. leaf flower) due to old age or stress.
achene: Small dry indehiscent fruit that has a single seed (as in e.g. Polylepis).
acicular: Needle-shaped.
acorn: Fruit of Quercus; a single-seeded nut set in a woody cupule.
actinomorphic: Radially symmetrical. Applied to flowers with multiple lines of symmetry passing through their centre (e.g. Malus). (Cf. zygomorphic.)
acuminate: Narrowing gradually to a point.
acute: Sharply pointed.
adaxial: (especially of surface of a leaf) Upper; facing towards the axis. (Cf. abaxial.)
adherent: In close contact with a different part but not fused to it.
adnate: Fused with a different part by having grown together. (Cf. connate.)
allopatric: With a different distribution to that of another taxon. (Cf. sympatric.)
alluvial: Sediments deposited by rivers or soils derived from such material.
alternate: Attached singly along the axis not in pairs or whorls.
amphistomatic: With stomata on both sides of the leaf.
amplexicaul: (of leaf) With a base that clasps the stem but does not entirely surround it.
androdioecious: With only male or only hermaphrodite flowers on individual plants.
androecium: Collective name for the male sex organs in a flower (e.g. the stamens).
anther: Pollen-producing structure of flower at the tip of the filament; part of a stamen.
anthesis: Flowering period; when flower fully open and pollen beginning to be shed.
apex: (pl. apices) Tip. apical At the apex.
apiculate: With a short sharp point.
apocarpous: Flower in which the carpels are not fused together (e.g. many Magnolia spp.). (Cf. syncarpous.)
apomict: Taxon that reproduces only or regularly by apomixis.
apomixis: Reproduction without fertilisation usually by the asexual production of seeds (agamospermy) (as in e.g. Citrus Sorbus). Includes vegetative reproduction (stolons rhizomes suckers etc.) (as in e.g. Ulmus).
apophysis: The exposed tip of a seed scale in a mature closed conifer cone. Particularly significant in the genus Pinus.
appressed: Lying flat against an object.
apud: (after name(s) of the author(s) of a plant name) Literally ‘in the writings of’. Usually used where the name was published by one author or authors in the work of another.
archaeophyte: A non-native plant introduced to an area in ancient times (pre-1500 AD in the United Kingdom).
aril: Fleshy outgrowth produced at the base of a seed (as in e.g. Taxus). Often acts to attract animal seed-dispersal agents.
aristate: Bearing a stiff awn.
article: (in Casuarinaceae) Portion of branchlet between each whorl of leaves.
articulated: Jointed.
asl: Above sea-level.
assurgent: Curving or growing upwards.
attenuate: Gradually narrowing.
auricle: Small lobe or ear-like appendage.
auriculate: With one or more auricles.
authority: The author(s) of a plant name. The names of these authors are stated directly after the plant name often abbreviated. For example Quercus L. (L. = Carl Linnaeus); Rhus wallichii Hook. f. (Hook. f. = Joseph Hooker filius i.e. son of William Hooker). Standard reference for the abbreviations: Brummitt & Powell (1992).
autopolyploid: State of increased ploidy resulting from doubling of the normal two sets of chromosomes in a single species.
awn: Bristle.
axil: Angle between the upper side of a leaf and the stem.
axillary: Situated in an axil.
backcross: Cross between hybrid and one of the parent species.
berry: Fleshy indehiscent fruit with seed(s) immersed in pulp.
bifid: Divided up to halfway into two parts.
bilateral symmetry: See zygomorphic.
bisexual: See hermaphrodite.
bletted: (of fruit) Softened into edibility by frost or fungi.
bloom: Bluish or greyish waxy substance on leaves or fruits.
brachyblast: A short lateral flower-bearing shoot in Magnolia (primarily in species formerly in Michelia).
bract: Reduced leaf often subtending flower or inflorescence.
bract scale: (in female cones of Pinaceae) Papery structures that subtend the seed scales. Derived from modified leaves and may be included (e.g. Tsuga) or exserted (e.g. Pseudotsuga). In other conifer families bract scale and seed scale are fused.
bracteole: Small bract. Typically borne on pedicel of a flower.
branchlet: Small branch or twig usually less than a year old.
bud: Immature shoot protected by scales that develops into leaves and/or flowers.
bud scale: Reduced scale-like leaf partially enclosing a bud.
bullate: Puckered; with blister-like swellings on the surface.
buttress roots: Roots produced from the stem above ground that gradually fuse with the main stem providing additional mechanical support. buttressed (of stem) With buttress roots.
caducous: Falling off early.
caespitose: Tufted.
calcareous: Relating to lime- or chalk-rich soils or water.
calcicole: (of a plant) Growing on soil containing lime.
calcifuge: (of a plant) Avoiding soil containing lime (i.e. usually growing on acidic soil).
calyptra: Cap-like structure that covers some flowers. Derived from fused-together petals and/or sepals. In Eucalyptus for example flowers may have either a single calyptra (sepals and petals) or an inner one (petals) and an outer (sepals).
calyx: (pl. calyces) Outer whorl of the perianth. Composed of several sepals.
cambium: Meristematic (actively dividing) cells in the stem responsible for stem expansion (secondary growth).
campanulate: Bell-shaped.
camptodromous: Pattern of leaf venation whereby the lateral veins bend just before reaching the margin forming a loop. (Cf. craspedodromous.)
capitate: Head-like.
capitulum: (pl. capitula) Literally ‘head’; (in plants) head-like inflorescence of sessile (or almost sessile) flowers surrounded by ring of bracts (involucre). Typical of daisies Asteraceae.
capsule: Dry dehiscent fruit; formed from syncarpous ovary.
carpel: Female reproductive organ of a flower. Composed of ovary style and stigma. Typically several carpels are fused together in each flower (syncarpous). The number of them can be of taxonomic significance; it can often be assessed by counting the stigma branches or the chambers in the fruit.
cartilaginous: Firm and tough but flexible; gristly.
cataphyll: A reduced leaf. In Pinus cataphylls are scale-like non-photosynthetic leaves that line the stem.
caudate: With a long tail-like appendage.
cauliflorous: Exhibiting cauliflory.
cauliflory: Production of flowers directly on the trunk and stems (as in e.g. Cercis) rather than at stem apex.
CBD: Convention on Biological Diversity.
chaparral: Dense vegetation consisting of low scrubby trees and shrubs often with small leaves and spines.
chartaceous: Paper-like.
ciliate: Fringed with long hairs.
CITES: Convention on International Trade in Endangered Species of Wild Fauna and Flora.
clonal reproduction: Reproduction without the exchange of genetic material; asexual reproduction.
clone: Organism arising via vegetative or asexual reproduction.
coetaneous: The production of flowers/inflorescences during leaf emergence. (Cf. precocious serotinous.)
compound: Made up or consisting of two or more similar parts (e.g. a compound leaf is a leaf with several leaflets).
concolorous: Having the same colour throughout.
conduplicate: (of leaves) Folded once lengthwise.
cone: Term used here primarily to indicate the seed-bearing (female) structure of a conifer (‘conifer’ = ‘cone-producer’); otherwise known as a strobilus. A number of flowering plants produce cone-like seed-bearing structures including Betulaceae and Casuarinaceae.
cone scale: A scale in a cone. In Pinaceae this term generally refers to the seed scale while in other conifer families it refers to the combined complex of bract and seed scale.
connate: Fused together with a similar part. (Cf. adnate.)
convex: Having a rounded surface.
cordate: Heart-shaped (i.e. with two equal lobes at the base).
coriaceous: Leathery.
corolla: The inner whorl of the perianth. Composed of free or united petals often showy.
corymb: Unbranched inflorescence with lateral flowers the pedicels of which are of different lengths making the inflorescence appear flat-topped.
corymbose: In form of corymb.
cotyledon: The leaf/leaves of an embryo plant (‘seed leaves’) that may emerge from the seed and become photosynthetic or may remain within the seed.
craspedodromous: Pattern of leaf venation whereby the lateral veins run straight out to leaf margin. (Cf. camptodromous.)
crenate: With rounded teeth at the edge.
crenulate: With small rounded teeth at the edge.
crisped: Curled or crumpled.
Critically Endangered: IUCN Red List conservation category: ‘facing an extremely high risk of extinction in the wild’.
crustaceous: Somewhat hard elastic; resembling a hard crust or shell.
cultivar: (cv., cvs) Cultivated variety; cultivated plant selected for feature(s) that is/are useful and/or appealing to growers that is clearly distinct uniform and stable in its characteristics and remains so when propagated. A cultivar is indicated by single quotation marks around the name (e.g. Quercus rysophylla ‘Maya’). For the rules on naming a cultivar see the International Code of Nomenclature for Cultivated Plants.
cultivar group: See Group.
cuneate: Wedge-shaped.
cupular: Cup-shaped; relating to the cupule.
cupule: Cup-shaped structure formed from coalescent bracts. Typical of Fagaceae and Nothofagaceae. May be dehiscent (as in e.g. Castanea) or indehiscent (as in e.g. Quercus).
cusp: A pointed end; curves meeting in a point.
cuspidate: Ending abruptly in a sharp point.
cyme: Branched determinate inflorescence with a flower at the end of each branch. cymose In the form of a cyme.
Data Deficient: IUCN Red List conservation category: ‘there is inadequate information to make a direct or indirect assessment of its risk of extinction based on its distribution and/or population status’.
dbh: Diameter (of trunk) at breast height. Breast height is defined as 4.5 feet (1.37 m) above the ground.
decurrent: Running down as when a leaf extends along a stem.
decussate: Leaf arrangement where the leaves are in opposite pairs each pair at right angles to the preceding pair (as e.g. the scale leaves of Cupressaceae).
deflexed: Bent or turned downwards.
dehiscent: Opening naturally. (Cf. indehiscent.)
deltoid: Triangular.
dentate: With evenly triangular teeth at the edge. (Cf. crenate teeth rounded; serrate teeth saw-like.)
denticulate: Minutely (triangularly) toothed.
determinate: A form of inflorescence in which the terminal flower is the first to open preventing further extension of the inflorescence axis. (Cf. indeterminate.)
dichasium: A type of cyme with lateral branches on both sides of the main axis.
dichotomous: Forked dividing into two.
digitate: Hand-like; palmate.
dimorphic: Occurring in two forms.
dioecious: With male and female flowers on separate plants.
dioecy: The condition of being dioecious.
discoid: Flat and circular.
disjunct: Discontinuous; (of a distribution pattern) the range is split into two or more distinct areas.
distal: Situated away from point of attachment. (Cf. proximal.)
distichous: Arranged in two vertical ranks.
divaricate: Widely spreading greatly divergent. Many trees and shrubs from New Zealand have a divaricating form particularly when young whereby the stems become interlaced producing a ‘wire-netting’ effect.
divergent: Spreading from the centre.
DNA: Deoxyribose nucleic acid the principal genetic material.
domatia: Cavity or tuft of hairs that acts as a shelter for insects or other creatures.
dorsiventral flattening: Where a structure is flattened from top to bottom rather than from side to side.
drupe: A fleshy dehiscent or indehiscent fruit with one to several seeds each enclosed in a hard endocarp (the stone).
ellipsoid: An elliptic solid.
emarginate: Notched at the apex.
Endangered: IUCN Red List conservation category: ‘considered to be facing a very high risk of extinction in the wild’.
endemic: (of a plant or an animal) Found in a native state only within a defined region or country.
endocarp: Innermost layer of the fruit wall. Can be membranous and indistinguishable from the other layers of the fruit wall or may be hard woody and distinctive (see drupe).
entire: With an unbroken margin.
epicalyx: Whorl of sepal-like organs just outside the true calyx.
epicarp: Outermost layer of the fruit wall; the ‘skin’ on fruits such as apples and plums.
epicormic: (of shoot) Growing out from trunk or major branches.
epidermis: Outermost layer of cells (e.g. covering leaves).
epimatium: Expanded fleshy seed-bearing bract scale enclosing the seed in Podocarpaceae.
epiphyte: Plant growing on trees but not parasitic on the host.
epistomatic: Possessing stomata only on upper side of leaf.
equisetoid: Resembling the growth of an Equisetum (horsetail).
ex: (appearing before the author(s) of a plant name) Indicates the author who published the plant name validly. For example Quercus floribunda Lindl. ex A. Camus: ‘ex’ denotes that the latter author (Aimée Camus) published the name validly; the name had been used previously by the former author (John Lindley) but had not been validly published by him.
exserted: Protruding; pushed out.
Extinct: IUCN Red List conservation category: ‘there is no reasonable doubt that the last individual [of taxon] has died’.
Extinct in Wild: IUCN Red List conservation category: ‘known only to survive in cultivation in captivity or as a naturalised population (or populations) well outside the past range’.
extrafloral: Outside the flower. Used to describe nectaries situated on vegetative parts of a plant.
extrapetiolar: Outside the petiole. Used to describe stipules that are attached to the stem rather than to the petiole.
F1: A first-generation hybrid between two individuals.
F2: The second generation of progeny from an original hybridisation event; derivatives from the generation.
facial pair: In the Cupressaceae the scale leaves are arranged in alternating pairs (see decussate). The pair comprising the upper and lower leaves are the facial pair. (Cf. lateral pair.)
falcate: Sickle-shaped.
family: A group of genera more closely related to each other than to genera in other families. Names of families are identified by the suffix ‘-aceae’ (e.g. Myrtaceae) with a few traditional exceptions (e.g. Leguminosae).
farinose: Covered with fine powder. (Cf. mealy.)
fascicle: Close cluster or bundle; reduced short shoot of Pinus.
fascicle sheath: Cluster of membranous bud scales at the base of the fascicle in Pinus.
fastigiate: (of a tree or shrub) Narrow in form with ascending branches held more or less parallel to the trunk.
ferruginous: Rust-coloured.
filament: (in a plant) Stalk of a stamen supporting the anther.
filiform: Thread-like.
fimbriate: Fringed with edge dissected into long narrow lobes.
flabellate: Fan-shaped.
flush: Coordinated growth of leaves or flowers. Such new growth is often a different colour to mature foliage.
fluted: Channelled or grooved.
foliose: Leaf-like.
follicetum: Body made up of several follicles.
follicle: Dry dehiscent fruit containing numerous seeds derived from a single carpel.
form: (f.) Lowest taxonomic rank (forma) into which an organism is normally classified. Usually showing minor differentiation in only one character and not forming distinct populations.
fusiform: Spindle-shaped; a gradually tapering rod.
fynbos: Extremely biodiverse vegetation in the Western Cape of South Africa dominated by short finely branched shrubs.
galbulus: The fruit of Juniperus; a modified cone that becomes fleshy as it matures.
gallery forest: Thin strip of forest adjacent to a river in an otherwise unwooded landscape.
garrigue: Short Mediterranean scrubland.
genus: (pl. genera) A group of species more closely related to each other than to species in other genera. generic Of genus.
germplasm: Seed.
glabrous: Lacking hairs smooth. glabrescent Becoming hairless.
glandular: Bearing glands.
glaucescent: Becoming glaucous; (incorrectly) slightly glaucous.
glaucous: Grey-blue often from superficial layer of wax (bloom).
globose: globularSpherical or globe-shaped.
group: (or cultivar group) Collective name for a number of cultivars within a genus or species with similar characteristics. A very useful modern concept enabling the naming of many similar plants without the need to provide a cultivar name for each: so for seed-raised plants that come nearly true from seed (as e.g. Quercus texana New Madrid Group); or for the progeny of a repeatable hybridisation; or for variants of a species that cannot be maintained as distinct entities by taxonomists but have horticultural merit and need to be distinguished. ‘Group’ is always included in the name. Named cultivars may be selected from within a cultivar group.
gymnocarpy: Bare seeds protruding from the cone in Juniperus due to insect damage.
gynoecium: The female sex organs in a flower (e.g. carpels).
herbarium: A collection of preserved plant specimens; also the building in which such specimens are housed.
herbarium specimen: A plant specimen preserved (usually by drying or pickling) and maintained to provide information for botanists particularly taxonomists.
hermaphrodite: Having both male and female parts in a single flower; bisexual.
hesperidium: Type of berry in which the flesh is divided into segments with tough and leathery outer skin (as in e.g. Citrus).
heteroblasty: Production of different leaf forms at different ages. Very common in New Zealand native plants (e.g. Elaeocarpus hookerianus) and many Araliaceae.
hilum: Scar on seed from its point of attachment in the ovary. Particularly prominent on the large seeds of Aesculus.
hirsute: Covered in rough coarse hairs.
hyaline: Thin colourless translucent.
hybrid: Plant originating from the cross-fertilisation of genetically distinct individuals (e.g. two species or two subspecies).
hybrid swarm: A group or population of hybrids that exhibit a range of characters between those of the parents.
hybrid vigour: Increased expression of characteristics in hybrids when compared with the parent taxa.
hypanthium: Cup-shaped or tubular structure at the base of a flower (‘floral cup’) formed by enlargement of the receptacle and/or the bases of the floral parts.
hypogynous: With ovary situated below floral parts (inferior).
hypostomatic: With stomata only on lower side of leaf.
IDS: International Dendrology Society sponsors of this book.
ILDIS: International Legume Database & Information Service.
imbricate: Overlapping.
imparipinnate: Odd-pinnate; (of a compound leaf) with a central rachis and an uneven number of leaflets due to the presence of a terminal leaflet. (Cf. paripinnate.)
included: (botanical) Contained within another part or organ.
indehiscent: Not opening naturally; remaining closed at maturity. (Cf. dehiscent.)
indeterminate: A form of inflorescence in which the outer or lower flowers open first and the inflorescence axis continues to grow. (Cf. determinate.)
Index Seminum: Seedlist issued by a botanic garden for exchange purposes.
indigenous: Native to an area; not introduced.
indumentum: A covering of hairs or scales.
inflorescence: Flower-bearing part of a plant; arrangement of flowers on the floral axis.
infra-: Below the rank of. As in ‘infrageneric’ ‘infraspecific’ referring to subdivisions of these taxa.
infructescence: Fruit-bearing part of a plant; derived from an inflorescence.
INRA: Institut National de la Recherche Agronomique (French National Institute for Agricultural Research).
interfertile: Capable of interbreeding with another species or species to give hybrids.
intergeneric: (of hybrids) Formed by fertilisation between species of different genera.
internode: Section of stem between two nodes.
interspecific: (of hybrids) Formed by fertilisation between different species.
introgression: Incorporation of genes from one species into the genotype of another through repeated hybridisation or repetitive backcrossing between a hybrid and one of its parents.
involucre: A ring of bracts surrounding an inflorescence.
involute: Rolled inwards at margins (i.e. towards upper surface).
IPNI: International Plant Names Index. Database of plant names and associated details.
IUCN: World Conservation Union (formerly the International Union for the Conservation of Nature).
karst: Landscape area formed by the dissolution of limestone by water with much exposed rock. Karst areas are usually rather arid due to the free-draining conditions.
keel petal: (in the flowers of some legumes) The two front petals fused together to form a keel-like structure.
keeled: With a prominent ridge.
key: (of fruit) Vernacular English term for winged samaras (as in e.g. Acer Fraxinus Ulmus)
lamina: Leaf blade.
lanceolate: Lance-shaped; broadest in middle tapering to point.
lateral pair: (in Cupressaceae) The pair of lateral scale leaves. (Cf. facial pair.)
latex: Colourless or milky sap produced by some plants (e.g. many Apocynaceae Euphorbiaceae Moraceae).
laurisilva: Humid subtropical forest with high preponderance of Lauraceae; characteristic forest of Macaronesian islands.
lax: Loose or open.
leaflet: Leaf-like segment of a compound leaf.
Least Concern: IUCN Red List conservation category: ‘does not qualify for Critically Endangered Endangered Vulnerable or Near Threatened. Widespread and abundant taxa are included in this category.’ ‘Lower Risk’ was formerly used and many tree species are still so-categorised in the Red List.
lectotype: Specimen or illustration chosen to serve as the type specimen for a taxon in cases where one was not designated by the original author.
legume: Two-valved fruit formed from a single carpel widely known as a ‘pod’ typical of most members of the legume family (Leguminosae). The word has come to be used as much for members of the family as for their distinctive fruits.
lenticel: Pore on the stem. lenticellate Bearing lenticels.
lenticular: Lens-shaped.
liana: Woody climber growing from ground into canopy.
lignotuber: Woody tuber developed in the axils of the cotyledons or the first few leaf pairs. Common in Eucalyptus where they provide a means for regeneration after a fire.
ligulate: Tongue-shaped.
linear: Strap-shaped.
lobe: Division of a leaf or other object. lobed Bearing lobes.
locule: Compartment of the ovary. loculicidal (of dehiscent fruit) Splitting between the locules. (Cf. septicidal.)
lomentum: Fruit derived from a single carpel which splits into one-seeded sections (as in e.g. Sophora).
Lower Risk: See Least Concern.
lustrous: Smooth and shiny.
Macaronesia: The subtropical islands of the north Atlantic: the Azores Canary Islands Cape Verde Islands and Madeira.
Malesia: Floristic region including the Malay Peninsula Indonesia the Philippines and New Guinea.
mallee: Multistemmed growth form of many Eucalyptus species in which numerous stems arise from ground level from an individual plant (from the lignotuber).
maquis: Tall Mediterranean drought-resistant shrubland.
matorral: Scrub vegetation composed of low-growing woody plants derived by degradation of Mediterranean forest.
mealy: Covered with coarse flour-like powder. (Cf. farinose.)
medial: Relating to the middle or median.
mesa: Flat-topped steep-sided mountain often in arid areas.
mesic: (of habitat or site) Moderately moist. (Cf. xeric.)
mesocarp: Middle layer of the fruit wall in between the epicarp and the endocarp; the ‘flesh’ of fruits such as plums.
mesophytic: (of a plant) Growing in moist (mesic) habitats.
metapopulation: ‘Population of populations’ usually referring to scattered populations of the same species.
microspecies: Species distinguished on the basis of minute differences of morphology. Generally used only for species that reproduce via apomixis (e.g. Sorbus).
microsporophyll: Pollen-producing scales in the male cones of conifers.
midrib: midveinCentral and principal vein in a leaf.
moniliform: Like a string of beads.
monoecious: With male and female flowers on the same plant.
monoecy: The condition of being monoecious.
monograph: Taxonomic account of a single genus or family.
monomorphic: Occurring in one form.
monophyletic: (of a group of taxa) With a single ancestor; part of a natural lineage believed to reflect evolutionary relationships accurately (n. monophyly). (Cf. paraphyly polyphyly.)
monopodial: With simple stem/axis extending by growth of the apical bud and bearing lateral branches. (Cf. sympodial.)
monoseed: With a single seed. Many junipers in Juniperus section Sabina produce monoseed cones.
monospecific: (of a genus) Including only one species (as e.g. Aextoxicon).
montane: Of mountains.
morphology: The visible form of an organism.
morphometric: From the measurement of shape.
mucro: Short straight point. mucronate Bearing a mucro.
mutation: Novel characteristic arisen as a result of a spontaneous genetic change mutant Individual with a mutation.
mycorrhiza: (pl. mycorrhizae) Beneficial fungus associated with the roots of a plant. Different forms of association occur (e.g. arbuscular ectendo- endomycorrhizae) depending on how the fungus and the plant roots interact.
Near Threatened: IUCN Red List conservation category: ‘does not qualify for Critically Endangered Endangered or Vulnerable now but is close to qualifying or is likely to qualify for a threatened category in the near future’.
nectary: Gland or surface from which nectar is secreted.
node: Point on a stem where one or more leaves are borne.
nomen ambiguum: (nom. ambig.) (of plant name) Name whose application is ambiguous which could cause confusion.
nomen illegitimum: (nom. illeg.) (of plant name) Illegitimate name published with some contravention of the International Code of Botanical Nomenclature and therefore invalid.
nomen nudum: (nom. nud.) (of plant name) Name published without a description and therefore invalid.
notho-: (prefixed to the name of a taxon) Denotes hybrid origin. Hence nothogenus. nothospecies nothovar.
nut: Dry indehiscent single-seeded fruit with woody outer wall.
nutlet: Small nut. Term may also be applied to an achene or part of a schizocarp.
ob-: (prefixed to technical term) Inverse of.
oblanceolate: Inversely lanceolate; broadest towards apex.
oblate: Almost globose but flattened at apices; subglobose.
obtuse: Blunt.
open pollinated: Pollinated without control. Where plants are open pollinated unexpected hybrids may occur.
orbicular: Circular.
ovary: Lowest part of the carpel containing the ovules; later developing into the fruit.
ovate: Egg-shaped; broadest towards the stem.
ovoid: Egg-shaped solid.
ovule: Structure inside ovary that when fertilised becomes a seed.
palmate: Roughly hand-shaped; (of a leaf) divided partially or fully to the base with all the leaflets arising from the tip of the petiole (as in e.g. Aesculus).
panicle: A much-branched inflorescence. paniculate Having the form of a panicle.
papillae: Small protuberances on surface of petal or leaf sometimes hair-like in appearance. papillose Bearing papillae.
páramo: Vegetation above the treeline in tropical South America mostly grasslands and scrub.
paraphyletic: (of a taxon usually at generic or family level) With a common ancestor but some of the other descendants of that ancestor are excluded from the taxon for subjective reasons of the taxonomist (n. paraphyly). Such a classification is therefore not ‘natural’. (Cf. monophyly, polyphyly.)
paripinnate: Even-pinnate; (of a compound leaf) with a central rachis and an even number of leaflets (no terminal leaflet). (Cf. imparipinnate.)
pectinate: Comb-like.
pedicel: Stalk of a single flower.
pedicellate: Borne on pedicel.
peduncle: Stalk of inflorescence.
pedunculate: With a peduncle.
peltate: Disc-shaped and attached at centre of lower surface to a stalk (e.g. leaf of Nasturtium Tropaeolum majus).
pendent: Hanging.
perfect: (botanical) All parts present and functional. Usually referring to both androecium and gynoecium of a flower.
perhumid: Always moist or wet. Usually referring to tropics.
perianth: Calyx and corolla. Term used especially when petals and sepals are not easily distinguished from each other.
perular scale: Basal scales in a leaf bud.
petal: Single segment of the corolla. Often brightly coloured and an attractant for pollinators.
petaloid: Petal-like. May refer to sepals or stamens modified into a petal-like form.
petiolate: Bearing a petiole.
petiole: Leaf stalk.
petiolule: Stalk of a leaflet in a compound leaf.
phenology: The seasonal timing of events in the life cycle of a plant or animal and the study thereof.
phloem: Sap-carrying vascular tissue.
phototropism: A plant’s response to light: shoots growing towards it roots away.
phyllichnia: (in Casuarinaceae) Longitudinal ridges on articles.
phyllode: A petiole taking on the form and functions of a leaf (as in e.g. Acacia).
phylloid: Leaf-like.
pilose: Softly hairy.
pinna: (botanical) Primary division of a compound leaf.
pinnate: (of a compound leaf) With leaflets/ veins along each side of a central rachis/midrib.
pinnatifid: (of a leaf) Dissected into large teeth or lobes that reach no more than halfway to the midvein.
pinnatinerved: Leaf venation with a pinnate arrangement.
pinnatisect: (of a leaf) Dissected into large teeth or lobes that reach nearly to the midvein (i.e. not completely pinnate).
pinnule: Secondary division of a compound leaf.
pioneer species: Early colonists of disturbed areas.
pistillate: Female referring to female plants (dioecy) or flowers (monoecy) or the female parts of a hermaphrodite flower.
plicate: Folded more than once lengthwise.
ploidy: Number of chromosomes.
podzol: A soil characterised by a superficial layer of raw humus above a generally grey layer of mineral soil depleted of iron sesquioxides and aluminium.
pollen: Small grains that contain the male reproductive cells. Produced in the anther.
pollination: Act of placing pollen on the stigma. Various agents may initiate pollination including animals and the wind.
polygamous: With unisexual and bisexual flowers on same plant.
polyphyletic: (of a taxon) Including entities descended from different ancestors and evolutionary lineages grouped usually as a result of superficial similarities (n. polyphyly). The grouping is therefore not ‘natural’. (Cf. monophyly paraphyly.)
pome: Fleshy fruit with leathery core. Typical of Rosaceae subfamily Maloideae (e.g. Malus).
precocious: The production of flowers/inflorescences prior to leaf emergence. (Cf. coetaneous serotinous.)
propagule: Vegetative structure that can become detached and give rise to a new plant.
prostrate: Lying flat.
protologue: Text of first publication of a taxon’s name.
proximal: Situated towards point of attachment. (Cf. distal.)
pruinose: Covered with a waxy bloom (as found on a plum).
puberulent: Minutely pubescent.
pubescence: Hairiness.
pubescent: Covered in hairs.
pulvinus: (pl. pulvini) Enlarged portion of petiole or rachis.
punctuate: Marked with dots depressions or glands.
pyrene: Stone of a drupe consisting of the seed and the surrounding endocarp.
pyriform: Pear-shaped.
raceme: Unbranched inflorescence with flowers produced laterally usually with a pedicel. racemose In form of raceme.
rachilla: (pl. rachillae) Secondary axis in an inflorescence.
rachis: Central axis of an inflorescence cone or pinnate leaf.
radial symmetry: See actinomorphic.
ramiflory: Production of flowers directly on the branches. Included within cauliflory. ramiflorous Exhibiting ramiflory.
receptacle: Enlarged end of a flower stalk that bears floral parts; (in some Podocarpaceae) fleshy structure bearing a seed formed by fusion of lowermost seed scales and peduncle.
reflexed: Folded backwards.
relict species: Species that has survived unchanged from a previous age (a ‘living fossil’) or become geographically isolated from related species due to a change in circumstances.
reniform: Kidney-shaped.
resin canal: Minute tubes containing resin-producing cells in the leaves and wood of conifers.
resin gland: Small gland on leaf or other surface exuding resin.
reticulate: Arranged in a net-like manner.
retuse: Slightly notched at apex.
revolute: Rolled downwards at margin.
rhizome: Persistent horizontal subterranean stem bearing roots and shoots. rhizomatous Having or resembling a rhizome.
rhombic: Diamond-shaped. rhomboid Diamond-shaped solid.
rugose: Wrinkled.
s.l.: Abbreviation of sensu lato. In the broad sense.
s.n.: Abbreviation of sine numero. Without a number.
s.s.: Abbreviation of sensu stricto. In the narrow sense
sagittate: Arrowhead-shaped.
samara: Dry indehiscent winged fruit usually with a single seed (as in e.g. Acer Fraxinus Ulmus. Also called a ‘key fruit’.
sarcotesta: Fleshy outer coat on a seed (as in e.g. Ginkgo).
scabrous: Rough to the touch as a result of minute projections. scabrid Slightly less rough.
scarious: Thin dry and membranous.
schizocarp: Dry fruit that breaks up into sections at maturity.
sclereid: Hard thick-walled cell; part of the sclerenchyma the support tissue in plants. Individual sclereids also occur in the flesh of Pyrus fruits giving their characteristic gritty texture.
sclerophyllous: With tough leathery usually evergreen leaves. Typical of trees and shrubs from warm dry climates.
section: (sect.) Subdivision of a genus.
seed scale: (in female cones of Pinaceae) Seed-bearing structure. In other conifer families the seed scale and the bract scale are fused together.
self-coppicing: (of vigorous tree or shrub: e.g. Corylus) Producing new stems at ground level without having been damaged.
sensu lato: (s.l.) In the broad sense.
sensu stricto: (s.s.) In the narrow sense.
sepal: Single segment of the calyx. Protects the flower in bud.
septicidal: (of fruit) Splitting along the partitions (septa) rather than along the walls of the locules. (Cf. loculicidal.)
serotinous: The production of flowers/inflorescences after leaf emergence; (of cones/dry fruits) closed until scorched by fire (as in e.g. Banksia Pinus). (Cf. coetaneous precocious.)
serrate: With saw-like teeth at edge. serrulate Minutely serrate.
sessile: Lacking a stem or stalk.
setose: Bristly.
simple: (of a leaf) Unlobed or undivided.
sinuate: (of a flat leaf) With margins that wind strongly inwards and outwards.
sinus: Recess between two lobes or teeth on leaf margin.
sp. nov.: Abbreviation of species nova. A newly discovered species for which no epithet has been formally published.
spathulate: Spatula-shaped.
species: (sp. pl. spp.) Division of a genus; group of plants or animals with similar characters all more closely related to each other than to any other similar group. specific Of species.
spicate: Spike-like.
spike: Inflorescence in which flowers sessile on the main axis.
spinose: Spiny.
sporophyll: Specialised leaf or structure derived from a leaf that bears spore-producing bodies. The seed scale of a conifer cone is a megasporophyll while the scales in a male conifer cone are microsporophylls.
SSC: Species Survival Commission (of the IUCN).
stamen: Male reproductive organ of flower. Usually composed of an anther and a filament.
staminal ring: Ring of stamens.
staminate: Male referring to male plants (dioecy) or flowers (monoecy) or the male parts of a hermaphrodite flower.
staminode: Sterile or abortive stamen. Can be petaloid or converted into a nectary.
standard petal: (in the flowers of some legumes) Large upper petal; also known as ‘vexillum’.
stellate: Star-shaped.
stigma: (in a flower) The part of the carpel that receives pollen and on which it germinates. May be at the tip of a short or long style or may be reduced to a stigmatic surface at the apex of the ovary.
stipitate: Having a stalk (stipe) or borne upon one.
stipule: An outgrowth arising at the base of the petiole. Often paired. May be foliose or spinose caducous or persistent. stipulate Bearing stipules.
stoma: (pl. stomata) Small pores on the leaves (and young stems) that allow for gas exchange.
strangler: An epiphytic vine or tree whose roots extend down the trunk of a supporting tree and coalesce around it eventually strangling it.
stratify: (horticultural) Expose seeds to cold weather to promote germination.
striated: Bearing fine longitudinal stripes grooves or ridges.
strigose: Bearing stiff hairs or bristles.
strobilus: Cone. Used here to indicate male pollen-producing structure in conifers which may or may not be cone-shaped.
style: Generally an elongated structure arising from the ovary bearing the stigma at its tip.
stylopodium: Persistent remains of the style at tip of an acorn.
sub-: (prefixed to tech. term) Beneath; less than; approximately.
subspecies: (subsp.) Taxonomic rank for a group of organisms showing the principal characters of a species but with significant definable morphological differentiation. A subspecies occurs in populations that can occupy a distinct geographical range or habitat.
subulate: Awl-shaped.
symbiotic: (of two organisms) Dissimilar but closely associated living together in a mutually beneficial manner.
sympatric: With the same distribution as another taxon (or with overlapping distribution). (Cf. allopatric.)
sympodial: With stem/axis terminating (perhaps after the production of a flower) and growth continuing via lateral branches. (Cf. monopodial.)
syncarpous: Flower in which the carpels are fused together to form a single unit. (Cf. apocarpous.)
synonym: (syn.) (botanical) An alternative or former name for a taxon usually considered to be invalid (often given in brackets). Synonyms arise when a taxon has been described more than once (the prior name usually being the one accepted as correct) or if an article of the International Code of Botanical Nomenclature has been contravened requiring the publishing of a new name. Developments in taxonomic thought may be reflected in an increasing list of synonyms as generic or specific concepts change over time.
taiga: Region of sparse coniferous forest in northern latitudes.
taxon: (pl. taxa) Group of organisms sharing the same taxonomic rank (family genus species infraspecific variety).
taxonomy: Classification usually in a biological sense.
tepal: Perianth segment. Petal/sepal of a flower in which the two structures cannot be differentiated (as in e.g. Magnolia).
terete: Like a slender tapering cylinder.
ternate: In threes.
terrestrial: Growing in the ground.
thyrse: Mixed inflorescence in which main axis indeterminate but secondary axes determinate. thyrsoid In form of thyrse.
Tibet: Traditional English name for the formerly independent state known to its people as Bod now the Tibet (Xizang) Autonomous Region of the People’s Republic of China. The name Xizang is used in lists of Chinese provinces.
tomentum: Dense layer of soft hairs. tomentose With tomentum.
trichome: Hair-like growth from epidermis. May be glandular.
trifoliate: With three leaves or leaflets.
trifoliolate: With three leaflets.
trinerved: Three-nerved with the veins (nerves) all arising from near the base of the leaf.
triplinerved: Three-nerved with the two lateral veins (nerves) arising from the midrib above the base of the leaf.
TROBI: Tree Register of the British Isles.
TROI: Tree Register of Ireland.
trullate: Trowel-shaped.
truncate: Appearing as if cut off.
tuber: Underground storage organ derived from root or stem.
tubercle: Small tuber; small rounded projection or protruberance. tuberculate Bearing tubercles.
turbinate: Spinning-top shaped; inversely conical; obconical.
tylose: An obstruction of a connective vessel (xylem or phloem) caused by the intrusion of part of another cell.
type specimen: A herbarium specimen cited in a taxonomic account to define a particular species or other taxon.
umbel: Inflorescence in which pedicels all arise from same point on peduncle. May be flat-topped (as in e.g. Umbelliferae) to spherical (as in e.g. Araliaceae). umbellate In form of umbel.
umbellaster: Basic inflorescence unit in Eucalyptus; a group of flowers (with terminal bud ending in a flower) more or less arising from one point. May derive from cyme thyrse or panicle.
umbilicate: Having a small depression; resembling the human belly-button (umbilicus).
umbo: Boss or protuberance particularly that in centre of apophysis of pine seed scale. umbonate Bearing an umbo.
undulate: Wavy.
unicellular: Single-celled.
unifoliolate: Having one leaflet thus appearing to have simple (not compound) leaves.
unisexual: Having only male or female organs in a flower.
urceolate: Urn-shaped.
USDA: United States Department of Agriculture.
USDA Hardiness Zone: Defined in USDA Plant Hardiness Zone Map which divides the North American continent into ten zones each representing an area of winter hardiness for plants based on average annual minimum temperatures.
USNA: United States National Arboretum.
valvate: (of similar parts of a plant: e.g. petals) Meeting without overlapping; (of dehiscent fruit) opening via valves.
variety: (var.) Taxonomic rank (varietas) grouping variants of a species with relatively minor differentiation in a few characters but occurring as recognisable populations. Often loosely used for rare minor variants more usefully ranked as forms.
venation: Pattern of veins (nerves) especially in a leaf.
vernalisation: The priming of a plant response (e.g. germination flowering) by exposure to low temperatures in winter.
vernation: Arrangement of a leaf in its bud.
vesicle: Small bladder or sac.
vicariants: Similar usually related taxa found in similar habitat but in distant locations.
villous: Covered in long shaggy hairs.
viscid: Sticky.
Vulnerable: IUCN Red List conservation category: ‘facing a high risk of extinction in the wild’.
whorl: Arrangement of three or more organs (leaves flowers) around a central axis. whorled Arranged in a whorl.
wing petal: (in flowers of some legumes) The two lateral petals.
winter bud: Vegetative buds developed in the autumn and persisting through winter until spring when they burst.
x: (multiplication sign) Placed before an epithet indicates a hybrid; between two parents denotes a cross between them.
xeri-adapted: Adapted to tolerate dry conditions.
xeric: (of habitat or site) Arid. (Cf. mesic.)
xerophytic: (of a plant) Growing in arid (xeric) habitats.
Xizang: See Tibet.
xylem: Vascular tissue carrying water and minerals from roots.
zoopharmacognosy: Self-medication by animals.
zygomorphic: Bilaterally symmetrical. Term applied to flowers with a single line of symmetry passing through the centre (e.g. Salvia). (Cf. actinomorphic.)

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