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.
páramo
Vegetation above the treeline in tropical South America mostly grasslands and scrub.
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.
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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