GLOSSARY

Select a topic from the list below to see images of that trait:

Diagrams (Figures 1-16)

Leaf Parts

Leaf Arrangement

Leaf Attachment

Leaf Types

Leaf Shape

Leaf Apices

Leaf Bases

Leaf Margins

Armature

Flowering Time (Salix)

Pubescence A-H

Pubescence L-P

Pubescence S-V

Surfaces & Textures A-F

Surfaces & Textures G-L

Surfaces & Textures M-P

Surfaces & Textures R-Z

a-, ab-

Prefix meaning either 'away from' (Latin origin) or 'without' (Greek origin).

abaxial

The lower surface of a leaf, bract, sepal, or petal; the surface facing away from the stem of a plant or the axis to which it is attached.

abruptly acuminate

An apex that narrows suddenly to a short, pointed apex; e.g., apex of purple chokeberry (Aronia ×prunifolia) leaves.

acaulescent

Lacking an above-ground stem; e.g., stemless (acaulescent) violets, such as marsh blue violet (Viola cucullata).

accessory bud

An extra bud or buds located adjacent to, or above, a lateral bud; accessory buds located above a lateral buds are called 'superposed buds'; accessory buds located on either side of a lateral bud are called 'collateral buds'; e.g., black walnut (Juglans nigra) twigs have superposed buds), while red maple (Acer rubrum) twigs often have collateral buds.

accessory fruit

A category of fruits derived from an ovary plus other floral parts, such as the perianth, hypanthium, involucre, or an enlarged receptacle. There are several types of accessory fruit, including pomes (apples) and trymas (hickory), which are derived from a single ovary. Those accessory fruit derived from one flower with several ovaries, plus receptacle or hypanthium tissue, are called aggregate-accessory fruits; e.g., pseudocarps (strawberries), or rose hips (Rosa fruits). Accessory fruits are also called 'anthocarps' or 'anthocarpous fruit' in some books.

achene

A type of dry indehiscent fruit, formed from a superior ovary with a single carpel; all the layers of the pericarp (fruit wall) are dry and the single seed is attached only at the base of the fruit e.g., sunflower (Helianthus annuus), sedges (Carex spp.).

achenetum

An aggregate of small achenes, derived from a single flower with few to many separate (apocarpous) pistils, all attached to the same base; e.g., fruiting heads of avens (Geum) or buttercups (Ranunculus); formerly spelled 'achenecetum' (Spjut 1994).

achlorophyllous

Referring to plants that lack chlorophyll, such as mycoparasites; e.g., ghost pipe (Monotropa uniflora).

acicula

A short, slender, needle-shaped bristle, originating from the epidermis of a stem (plural: aciculi); e.g., shining rose (Rosa nitida).

acicular

Needle-shaped; long, slender, and sharply pointed; e.g., pine needles (Pinus spp.). See Figure 6.

acicular-tipped

A narrow, sharply-pointed, solid apex, usually 3-angled in cross-section, gradually forming and tapering from a flat or folded leaf blade; e.g., leaf apex of some sedges, such as the leaves of Michaux's sedge (Carex michauxiana).

acidicole

Growing on acidic substrates, such as granite, gneiss, or quartzite (adj.: acidicolous). From the Latin, -cola = dweller, exists only in.

acidifuge

Acid-avoiding; an organism unable to thrive in acidic soils or on acidic substrates; e.g., Newfoundland oxytrope (Oxytropis campestris var. minor). From the Latin: fugere = to flee from.

acidophile

Acid-loving, adapted to growing in acidic environments. Referring either to plants able to thrive in acidic soils, usually with a pH between 3.5 and 7, or referring to microorganism adapted to growing in ultra-acidic environments with a pH less than 3 (adj.: acidophilic or acidophilous). From the Latin, -philus = loving.

acidophilic

(adj.) Acid-loving; preferring to grow on acidic substrates (e.g., sandstone, granite); aka: acidophilous.

acidophyte

A plant adapted to growing in acidic soils (pH less than 7, usually between 4 and 5), or on acidic substrates, such as granite, sandstone, gneiss, or quartzite; e.g., lowbush blueberry (Vaccinium angustifolium), sheep sorrel (Rumex acetosella), and bunchberry (Cornus canadensis). From the Latin: -phyt = plant.

acorn

A type of accessory fruit, consisting of a nut (dry, indehiscent fruit with a hard pericarp enclosing one seed) subtended by a cup-like involucre (cupule) of small overlapping bracts. The technical name for acorn is 'glans'. The nut of an acorn, also called a 'calybium', develops from an inferior ovary with one locule; e.g., the fruit of red oak (Quercus rubra).

acropetal dehiscence

Dehiscence in an upward direction, from the base of the fruit toward the apex; e.g., the capsules of Labrador tea (Rhododendron groenlandicum) dehisce acropetally.

acropetal maturation

Maturation in an upward direction; in an inflorescence, maturation of flowers from the base toward the apex.

acroscopic leaflets

Leaflets situated above the rachis of a bipinnately compound leaf, i.e., on the side closest to the apex of the leaf.

acroscopic pinnules

Pinnules situated above the costa of a pinna , i.e., on the side closest to the apex of the frond.

actinomorphic

A type of floral symmetry in which a mirror image will be produced on both sides of a line drawn at any point through the centre of a flower; also called regular symmetry.

acuminate

A sharply pointed apex forming an angle less than 45°, with relatively straight margins that taper gradually to the tip; e.g., heartleaf birch (Betula cordifolia). See Figure 7.

acute

A pointed apex forming an angle between 45° and 90°; e.g. apex on the leaves of spotted jewelweed (Impatiens capensis). See Figure 7.

acyclic

Arranged spirally, as opposed to whorls or rows.

ad-

Prefix meaning 'towards' (Latin origin).

adaxial

The upper surface of a leaf, bract, sepal, or petal; the surface facing toward the stem of a plant or the axis to which it is attached.

adherent

With dissimilar structures stuck together, but not fused together (adnate).

adnate

The fusion of different structures, such as stamens adnate to a corolla, or stipules adnate to a petiole.

adventitious bud

A bud that develops in a position other than its usual placement, such as buds developing on the trunk of a tree to produce new shoots; adventitious buds are not associated with apical meristems.

adventitious root

A root that develops in a position other than its usual placement, such as roots developing from the side of the stem.

adventive

A relatively newly introduced species that is not yet well established in a given area.

aerial

Stems, shoots, or roots that grow above the ground; or in aquatic plants, shoots that extend above the water surface.

aggregate fruit

A category of fruits derived from a single flower with several distinct pistils attached to a common receptacle; the individual fruits are not connate (fused together) and can be easily separated. Also called an 'etaerio'. There are several types of aggregate fruits, including an aggregate of berries (baccacetum), an aggregate of achenes (achenetum), an aggregate of drupes (drupecetum), and aggregate of follicles (follicetum), and an aggregate of samaras (samaracetum); e.g., wild red raspberry (Rubus idaeus subsp. strigosus).

allogamy

Cross-fertilization; pollination and subsequent fertilization by pollen from a different flower or plant of the same species (adj.: allogamous).

alternate

A leaf arrangement with a single leaf attached at each node of the stem. See Figure 4.

alternation of generations

The kind of life cycle seen in the Embryophytes (bryophytes, pteridophytes, and seed plants); where a haploid (n) gametophyte generation produces gametes (egg, sperm) by mitosis, which fuse to form a diploid (2n) zygote that develops into a diploid sporophyte generation.

alveolate

A surface pattern with angular depressions surrounded by low ridges, forming a honeycomb-like pattern; e.g., pattern on shells of a peanut (Arachis hypogaea).

amphistomatic

Having stomates on both leaf blade surfaces, with the stomates distributed evenly across both surfaces (adj.: amphistomatous). A term used primarily in reference to willow (Salix) leaves. See also 'hemiamphistomatic' and 'hypostomatic'.

amplexicaulous

A sessile leaf with two basal lobes that surround and clasp the stem, but do not fuse around it; e.g., claspingleaf twisted-stalk (Streptopus amplexifolius).

androecium

Collective term for all of the male structures of a flower.

androgynecandrous

A bisexual spike of sedges (Carex) with unisexual staminate (male) flowers situated above and below the unisexual pistillate (female) flowers in the same spike; e.g., Buxbaum's sedge (Carex buxbaumii).

androgynous

A bisexual spike of some plants, especially sedges (Carex), with staminate (male) flowers situated above the pistillate (female) flowers in the same spike; e.g., awlfruit sedge (Carex stipata). See also 'gynecandrous'.

anemochory

Dispersal of fruits or seeds by wind (adj.: anemochorous).

anemophily

Pollination by wind (adj.: anemophilous); e.g., pines (Pinus) have anemophilous pollination.

angiosperms

Flowering plants; vascular plants that reproduce by seeds contained within fruits. Angiosperms are very diverse in form, but typically have flowers that may be showy or not, and broad leaves that may be evergreen or deciduous.

annual

A plant (or shoot, if stems are subterranean) that dies back to the ground each year, usually flowering and setting fruit just once in its life cycle.

annulus

A row of small, thick-walled cells that encircle a sporangium in higher ferns (leptosporangiate ferns). Dehiscence occurs along two thin-walled 'lip cells'. As the lip cells rupture, the annulus coils backward, forcibly expelling the tiny spores.

anthela

An open panicle-like cyme, found in some rush (Juncus) species, in which the lateral branches of the inflorescence are longer than the main inflorescence branch (adj.: anthelate).

anther

The pollen-producing portion of a stamen. See Figure 11.

anther cap

A protective covering situated over the pollinia in the flowers of most orchid species; also called an operculum.

anther sac

A chamber in the column of orchids where the pollinia are located.

anthesis

Generally, the start of flowering, when the flower buds open; specifically, when pollen is released and the stigma is receptive.

apex

The tip of a leaf; the end farthest away from the petiole or attachment point (plural: apices). See Figures 1, 7.

aphyllopodic

Fertile stems (culms) of Carex that bear leaves consisting only of bladeless basal sheaths. Aphyllopodic stems originate as lateral shoots of older vegetative shoots and do not have dead leaves persisting at their bases.

apiculate

With a small abruptly-pointed flexible tip; e.g., on leaflets of black medic (Medicago lupulina).

apiculus

A small abruptly-pointed tip, referring to the apex of the strobilus of some horsetail species (plural: apicula); e.g., scouring rush (Equisetum hyemale subsp. affine).

apocarpous

With 2 or more separate, distinct carpels in a single flower; e.g., tall buttercup (Ranunculus acris).

apophysis

In pines, the exposed end of a cone scale (seed-bearing scale), most visible when the scales of the cones are closed; e.g., on the cone scales of red pine (Pinus resinosa. (plural: apophyses).

appendage

Referring to petals: small flaps of extra tissue on each petal at the throat of the corolla; e.g., floral appendages occur in white campion (Silene latifolia).

appressed

Lying flat (or nearly so) against a surface and generally pointing in the same direction, forward or upward towards the tip of the structure; e.g., appressed hairs on the leaves of cottony willow (Salix eriocephala).

approximate

In close proximity, but not connected or fused.

aquatic

Describes plants that grow in the water, either entirely or partially.

arachnoid

A type of pubescence, bearing tangled, cobwebby-like hairs; e.g., the developing inflorescence of seabeach ragwort (Senecio pseudoarnica) is covered in arachnoid hairs.

arborescent

Resembling a tree in form.

arching

Curving or bending downward; e.g., arching stems of smooth blackberry (Rubus canadensis).

arcuate venation

A type of pinnate venation in which the secondary veins curve upward and inward towards the tip of the leaf. Arcuate venation is characteristic of dogwoods (Cornus species). See Figure 10.

areole (cacti)

Node-like areas on a cactus stem, equivalent to short-shoots, from which spines and glochids are attached.

aril

A fleshy, red, fruit-like outgrowth of the stalk (funiculus) of a yew seed, which grows upward, surrounding all but the apex of the seed; e.g., Canada yew (Taxus canadensis).

arillate seed

A seed partially enclosed within a brightly-coloured aril, a fleshy, transparent outgrowth produced by the outer layer (testa) of the seed coat; e.g., pomegranate seeds (Punica granatum).

armature

Collective term referring to any sharp, pointed, defense structure on stems or other plant parts, including barbs, bristles, prickles, spines, and thorns.

armed

Bearing any type of sharply pointed structure used for defence, such as barbs, aciculi, spines, prickles, or thorns.

array

Referring primarily to goldenrod (Solidago, Asteraceae) inflorescences; a compound inflorescence of capitula (heads), which may be organized in a variety of shapes. Also called a capitulescence. Arrays are similar in general form to basic inflorescence types, and may be spiciform (spike-like), racemiform (raceme-like), corymbiform (corymb-like), or paniculiform (panicle-like), etc.

articulated (general)

Jointed, not continuous, with a separating layer of tissue or abscission zone developing across the stem, petiole, or other structure.

articulated (horsetails)

In horsetails (Equisetum), the whorled leaves are fused (connate) into a sheath around the stem, with separate teeth at the top to the sheath; in some species, the individual teeth are jointed (articulated) at their base and deciduous at maturity; e.g. scouring rush (Equisetum hyemale var. affine).

ascending

Curving or bending upward and outward, not parallel to the stem.

ascidium

A hollow, pitcher-shaped leaf, usually associated with insectivorous plants (adj.: ascidiate); e.g., pitcher plant (Sarracenia purpurea).

asepalous

Without sepals.

asexual

A type of reproduction that does not include the production or fertilization of gamete; referring to plants that reproduce vegetatively through mitosis, producing new plants identical to the parent plant through the formation of bulbils or plantlets, or through fragmentation or layering.

association

A plant community of specific floristic composition, uniform physiognomy, and occurring in uniform habitat conditions (International Botanical Congress 1910). Associations are described based on a number of vegetation plots, or relevés, that have a number of species in common and can be recognized in the field by the presence of a diagnostic group of species (Mueller-Dombois and Ellenberg 1974).

asymmetric

Lacking symmetry; a type of floral symmetry in which any line through a flower will not produce a mirror image on both sides; e.g., canna lily (Canna indica).

attenuate apex

A long pointed apex that forms an angle less than 45°, upper leaf margins are concave and taper abruptly to the tip; e.g., hybrid crack willow (Salix ×fragilis). See Figure 7.

attenuate base

An abruptly tapering leaf base with concave lower margins that form an angle less than 45°; e.g., hairy goldenrod (Solidago hispida). See Figure 8.

auricle

A small ear-like lobe, usually at the base of a leaf or the upper (acroscopic) side of a fern pinnae or pinnule; e.g. auricles on pinnae of northern holly fern (Polystichum lonchitis).

auriculate

A leaf shape or base that expands abruptly into a basal pair of rounded or curved ear-like lobes (auricles); e.g., leaves of yellow rocket (Barbarea vulgaris). See Figures 6, 8.

auriculate sepal

A small flap of tissue at the base of violet (Viola) sepals, extending backwards toward the base of the flower; e.g., auriculate sepals of woolly blue violet (Viola sororia).

autochory

Dispersal of seeds by the plant's own means (adj.: autochorous).

autogamy

Self-fertilization; pollination and subsequent fertilization by pollen from the same flower (adj.: autogamous).

autopollination

A type of self-pollination found in some orchid species, in which the pollinia rotate from their normal position onto the stigmatic surface of the column without being transferred by a pollinator or other outside means; e.g., flowers of northern green bog orchid (Platanthera aquilonis).

autotrophic

Describes plants that produce their own food through photosynthesis.

awn

A stiff, slender, bristle-like structure terminating or attached to the back of floral bracts. In grass florets, the glumes, lemma, or palea may be awned; in sedges, the pistillate scales often bear a terminal awn, which may be smooth or barbed.

axil

The angle formed between a stem and any attached structure.

axillary bud

A bud produced in a leaf axil (the angle formed between a stem and a leaf); also called a 'lateral bud'.

axis

The central vertical stalk or an inflorescence or the main vertical stem of a plant (plural: axes).

azonal vegetation

The stable vegetation within a uniform climatic region that has developed on excessively dry or wet conditions; e.g., within the Central Newfoundland Ecoregion, the Piceetum marianae is the stable association on very dry shallow soils and gravels and the Sphagno-Piceetum Association is the azonal vegetation on wet organic soils.

ballochory

Dispersal of seeds by explosively dehiscent fruits (adj.: ballochorous); e.g., wood sorrel (Oxalis montana) has ballochorous fruit dispersal. Ballochory is a specialized type of autochory.

banner

In papilionaceous flowers, the upper petal of the flower, often 2-lobed; also referred to as the 'standard'.

bark

The outer waterproof layers of a tree trunk or woody stem.

barochory

Dispersal of fruits or seeds by gravity (adj.: barochorous).

basal leaf

A leaf attached at the base of a stem, but not attached along the stem.

basal sheath

A leaf sheath, usually lacking a blade, and located at the base of the flowering stems of sedges or grasses.

base

The lower or basal portion of a leaf blade. See Figures 1, 8 .

basipetal dehiscence

The splitting apart (dehiscence) of fruits from the apex towards the base; e.g., capsules of sheep laurel (Kalmia angustifolia) dehisce basipetally.

basiscopic leaflets

Leaflets situated below the rachis of a bipinnately compound leaf, i.e., on the side closest to the base of the leaf.

basiscopic pinnules

Pinnules situated below the costa of a pinnae, i.e., on the side closest to the base of a frond.

basophile

A plant adapted to growing in basic soils, a basophilic plant; aka: basophyte

basophilic

(adj.) Base-loving; preferring to grow on basic substrates (e.g., limestone or serpentine); aka: basophilous.

beak

The firm, pointed apex of a fruit, formed by a persistent style or floral tube; e.g., beaked achene-like fruit of stemless burreed (Sparganium acaule).

beaked capsule

A capsule with a long slender point at the apex, formed by the persistent styles or floral tube.

beard

A tuft of hairs, usually attached to the basal portion of petals or inside the tubular portion of a corolla, e.g., the number of bearded petals in violet (Viola) species is an important trait for identification.

berry

A simple indehiscent fruit derived from a superior ovary with a thin exocarp (skin) and fleshy mesocarp and endocarp. Grapes, tomatoes, kiwi, and bell peppers are all berries.

berry-like drupe

A drupe with a fleshy mesocarp and one or more small pits (endocarp) that each surround a seed.

bibacca

A type of multiple fruit; a fused double berry, formed by two pistils united at their base (plural: bibaccae); e.g., the fruit of a honeysuckle (Lonicera) flower is a bibacca.

bicolored

Two-coloured.

biconvex

Convex on both sides, also called 'lenticular'.

bifacial

2-faces, referring to leaves that have a distinct upper (adaxial) and lower (abaxial) surface; the vascular tissue then arranged with the phloem situated closest to the upper leaf surface and above the xylem, which is situated closest to the lower leaf surface. See also 'unifacial'.

bilabiate

Describes a type of corolla with an upper and lower lip, each lip formed by the fusion of 2 or more petals; the upper lip arches over the stamens and pistil, while the lower lip acts as a small landing platform for pollinators. Plants in the Mint Family (Lamiaceae) have bilabiate flowers.

bilateral symmetry

A type of irregular or zygomorphic floral symmetry, in which one line, drawn vertically through the flower, shows mirror images on the left and right sides of the line. A line drawn horizontally through the same flower will not produce identical images on either side of the line.

bipinnate

A twice pinnately compound leaf or frond, with each leaflet or pinnae further divided into smaller units.

bipinnate-pinnatifid

A twice pinnately divided frond with the upper portion pinnately lobed (pinnatifid), rather than divided to the rachis.

bisexual flowers

Flowers containing both male (stamens) and female (pistils) organs.

bivalvate sporangia

A primitive type of sporangium that splits into 2 halves to release its spores; e.g., moonworts (Botrychium).

bladder

A thin-walled, hollow, inflated or sac-like leaf that functions as a trap in some insectivorous plants; e.g., the traps of flatleaf bladderwort (Utricularia intermedia); equivalent to 'utricle' or 'ampulla' in the UK.

blade

The flat photosynthetic part of a leaf or frond.

bloom

(verb): The opening of a flower. (noun) Re: surface texture: A thin waxy or glaucous coating that covers the surface of a stem or fruit, and which can easily be removed by rubbing it.

bract

A small, modified, leaf-like structure, subtending a flower or a pedicel at the base of a flower. See Figure 14.

bracteole

A small bract, also called a 'bractlet'.

branchlet

A branch of the current year, capable of producing vegetative or flower buds.

bristle

A sharp stiff hair, originating from the epidermis (outer skin) of a stem; e.g., the bristly stems of wild raspberry (Rubus idaeus).

broadly crenate

A leaf margin with widely spaced, rounded or blunt teeth, e.g., the leaves of violet (Viola) flowers often have a broadly crenate margin. See Figure 9.

bud

Embryonic leaves or flowers on a stem, usually covered by one or more hard scales (modified leaves). Buds protected by scales are called 'scaly buds'; buds that lack scales are called 'naked buds'.

bud scale

A hard, modified leaf that protects the embryonic tissues of a bud from drought and cold.

bud scale scars

Narrow horizontal scars that mark where bud scales were attached to a stem. Terminal bud scale scars mark the beginning of each year's growth on a twig. See Figure 13.

bulb

A short underground stem surrounded by concentric rings of fleshy leaf bases; e.g., an onion is an example of a bulb.

bulbil

A small bulb-like structure that functions in vegetative reproduction, bulbils occur on above-ground stems, usually in leaf axils.

bulblet

A small bulb.

bulbous

Swollen at the base.

bundle trace scars

Minute circular or elliptic scars within a leaf scar that mark where the vascular bundles (vascular traces) entered the leaf from the stem. The number and arrangement of bundle trace scars is often characteristic of certain genera or species. See Figure 13.

bur

A dry involucre (modified phyllaries), covered in straight or hooked stiff bristles, that surrounds the actual fruit (cypselae) and functions in seed dispersal; e.g., burdock flowers have a bur surrounding their fruits.

caducous

Separating or dehiscing early; e.g., the stipules of some willow (Salix) species, or the caducous sepals of poppies (Papaver).

calceolate

Slipper-shaped or pouch-shaped, as in the lip of some orchids.

calcicolous

(adj.) Calcium-loving; preferring to grow on calcareous substrates (e.g., limestone, dolomite).

calcifuge

A plant that cannot thrive in calcareous or basic soils.

calciphile

A plant adapted to growing primarily on calcareous substrates; aka: calcicole or calciphyte.

callus

A waxy or fleshy growth that play a role in pollination, located along the base of the lip of some orchid flowers (plural: calli).

calyculus

A small bract that subtends the involucre of a composite head (plural: calyculi).

calyx

A collective term referring to all of the sepals of a flower, when the sepals are connate (fused to each other) (plural: calyces). See Figure 11.

calyx lobes

The free (unfused) apices of sepals in a calyx; calyx lobes are attached to the top of a calyx tube or hypanthium.

calyx tube

The tubular portion of a calyx; fused to the ovary in epigynous flowers; free from the ovary in hypogynous flowers.

campanulate

A bell-shaped corolla; e.g., as in harebell (Campanula) flowers.

capillary

Hair-like, very slender.

capitate

Ending in a small head, like the head of a pin; e.g., some pistils have a capitate stigma.

capitulescence

A secondary or compound inflorescence, composed of several to numerous heads (capitula); characteristic of plants in the Aster Family (Asteraceae).

capitulum

A type of inflorescence, composed of ray and/or disc flowers attached to a common receptacle; the primary inflorescence type of plants in the Aster Family (Asteraceae), also called a head; (plural: capitula); e.g., oxeye daisies (Leucanthemum vulgare). The capitulum (or head) is subtended by an involucre of overlapping bracts, called phyllaries. See Figure 15.

capsule

A dry, dehiscent fruit derived from an ovary with 2 or more carpels (a compound ovary). There are many different types of capsules, each described according to how they dehisce.

carinal canals

Small hollow tubular channels in horsetail stems, located opposite the stem ridges and associated with the vascular bundles (formed by the tearing of the protoxylem during growth). In cross-section, the carinal canals appear as a ring of small circles between the outer vallecular canals and the central canal.

carpel

Another word for pistil, referring to either a simple pistil or one segment of a compound pistil (with several carpels fused together). See Figure 11.

carpellate flower

Another name for a pistillate flower; a flower that contains only female reproductive organs.

carpophore

The persistent central axis of a fruit, remaining after the segments of the fruit (derived from a compound ovary) separate from the axis. Carpophores are found in the Carrot Family (Apiaceae) and Geranium Family (Geraniaceae).

caryopsis

A type of dry, indehiscent, 1-seeded fruit with the seed coat fused completely to the wall of the fruit. The type of fruit characteristic of plants in the Grass Family (Poaceae); also called a grain.

catkin

A spike-like inflorescence found in plants of the Willow (Salicaceae) and Birch (Betulaceae) Families. Each flower is subtended by one or more bracts; showy perianth parts (petals) are lacking. The axis of the catkin elongates as the flowers bloom.

caudate apex

An elongate tail-like leaf apex. See Figure 7.

caudex

The growing portion of a rootstock or rhizome, borne at or just below the surface of the soil, and giving rise to new leaves and flowering shoots in stemless (acaulescent) herbaceous plants; e.g., wild sarsaparilla (Aralia nudicaulis) plants develop from a caudex.

cauline leaf

A leaf attached to an above-ground stem; cauline leaves may have an alternate, opposite, or whorled arrangement.

central canal

The hollow centre of a horsetail stem; the relative size of the central canal to the diameter of the stem is important in identification of horsetail (Equisetum) species.

cespitose

Growing close to the ground in tight clumps or tufts, with new shoots developing laterally, adjacent to the older growth.

chaff

A collective term for the paleae on a composite receptacle.

channeled

A flat leaf with a longitudinal groove running the length of the leaf.

chartaceous

papery, with a paper-like texture; referring to the bracts of a sedge.

chasmogamous

Flowers that open for pollination to occur.

ciliate

Leaf margins with small straight hairs attached perpendicular to the margin. See Figure 9.

cincinnus

See 'scorpioid cyme' and Figure 16.

circinate vernation

The coiled arrangement of immature fronds in a fern crozier; the immature pinnae uncurl as the frond expands.

circumscissile capsule

A capsule that dehisces around the circumference of the fruit; e.g., plantain (Plantago) fruits have circumscissile dehiscence. Also called a pyxis.

clasping

A leaf in which the base or basal lobes closely surround the stem, but do not fuse around the stem. See Figure 5.

clavate

Club-shaped, with a blunt to rounded apex tapering gradually to the base.

claw

The narrow base of a petal.

cleft

Cut deeply into a leaf apex, base, or margin, forming straight-sided lobes. E.g., the leaf base of waterlily (Nymphaea odorata) leaves; or the apex of tulip tree (Liriodendron tulipifera) leaves. See Figures 7, 8, 9.

cleistogamous

Flowers that self-fertilize without opening; cleistogamous flowers are often smaller than chasmogamous flowers on the same plant and are borne close to the ground; e.g., violets (Viola) often have cleistogamous flowers.

cleistogene

Another name for a cleistogamous flower.

climax association

This term generally refers to the long-term stable vegetation that occupies a site in the absence of disturbance. Two types are commonly recognized: Climatic climax, where regional climate is the ecological driver of the species composition, and Edaphic climax, where significant change in geologic substrate or site moisture regime is the driver. Throughout most of Newfoundland the Abietum Association (Balsam Fir Forest Association) is recognized as the climatic climax association, whereas the Piceetum marianae (Black Spruce Forest Association) occupies extremely dry and wet soils. The black spruce forests that replace balsam fir forests following fire disturbance on nutrient-medium sites are referred to as Subclimax associations and will return to balsam fir dominance if left undisturbed.

coetaneous

With flowers that bloom at the same time as the leaves emerge. See also 'precocious' and 'serotinous'.

coherent

Held together as a unit, but not fused; not separating; e.g., the drupelets of raspberries form a coherent fruit that separates as a unit from the receptacle (torus).

column

A structure in orchid flowers formed by fusion of the style, stigma, and stamen parts (filaments and 1 or more anthers); also called a gynandrium. The size and shape of the column is often important in orchid identification.

coma

A terminal tuft of hairs attached to the apex of a seed; e.g., fireweed (Chamerion angustifolium) seeds have a coma.

compound corymb

A branched corymb, in which each of the pedicels is branched. See Figure 15.

compound cyme

A branched cyme, with a determinate central axis and lateral branches consisting of a simple cymes, each with a mature central flower subtended by a pair of flowers with pedicels of equal length. See Figure 16.

compound leaf

A leaf with the blade divided into 2 or more segments, or leaflets. Compound leaves may be pinnately compound or palmately compound, and leaflets may be sessile or stalked. See Figure 2.

compound umbel

A branched umbel, with the primary branches (rays) originating from the same point; secondary umbels (or umbellets) are found at the end of each ray. See Figure 15.

cone

The reproductive structure of gymnosperms, in which seeds are produced on the upper surface of cone scales; cones are usually hard and somewhat woody, but some genera, like juniper (Juniperus) have berry-like cones with few seeds.

cone scales

In gymnosperms, modified leaves that bear male or female sporangia, spirally arranged in male (staminate) or female (ovuliferous) strobili, commonly called cones.

conelet

An immature female cone.

connate

With similar parts fused together; i.e., connate petals form a corolla.

connate-perfoliate

A pair of opposite leaves with their bases fused together around the stem, forming a leaf in which the stem appears to go through the middle of the leaf blade. See Figure 5.

cordate

Heart-shaped; a 2-dimensional shape, basically ovate, but with 2 rounded basal lobes and a pointed apex. See Figures 6, 8.

cordate base

A leaf base with two prominent rounded lobes. See Figure 8.

coriaceous

A tough, leathery texture; e.g., the coriaceous leaves of wintergreen (Gaultheria procumbens).

corm

The short, fleshy, globose, underground stem of a geophyte, producing new growth each year; e.g, the corms of spring beauty (Claytonia caroliniana).

corolla

A collective term referring to all of the petals of a flower. The term corolla is used when the petals are connate to each other. See Figure 11.

corona

A petaloid crown-like flora structure situated between the stamens and the corolla. The trumpet of a daffodil (Narcissus) is a corona.

corymb

A flat-topped raceme; pedicels of lower flowers elongate to form a flat-topped indeterminate inflorescence (adj.: corymbose). A compound corymb is a branched corymb. See Figure 15.

corymbiform cyme

A determinate inflorescence (cyme) in which the central flower of the inflorescence is the oldest and the lower pedicels elongate as the flowers open and set fruit, forming a somewhat flat-topped inflorescence.

corymbiform raceme

An indeterminate inflorescence (raceme) in which the central flower of the inflorescence is the youngest and the lower pedicels elongate as the flowers open and set fruit, forming a somewhat flat-topped inflorescence.

costa

The main axis of a fern pinna (plural: costae).

costule

The main vein of a fern pinnule.

couplet

The paired statements in a dichotomous key; each statement or choice in a couplet is called a lead. Decisions are made between each lead of a couplet to reach an answer. See also 'dichotomous keys.'

crateriform

A bowl-shaped corolla, with distinct sides and a rounded or flat bottom; e.g.: the corolla of sheep laurel (Kalmia angustifolia) flowers.

crenate

Toothed margins with rounded or blunt teeth, like a scalloped edge; broadly crenate – with broad, blunt or low-rounded teeth. See Figure 9.

crenulate

Finely crenate; with small rounded or blunt teeth. See Figure 9.

crest

One or more ridges on the lip of some orchid flowers formed by a series of fleshy tooth-like or hair-like projections; e.g., the crested lip of dragon’s mouth (Arethusa bulbosa).

crozier

A circinnately coiled immature fern frond, also called a fiddlehead.

cruciform

Cross-shaped, as in the 4 petals of flowers in the Mustard Family (Brassicaceae, formerly called the Cruciferae).

culm

The aerial stem of grasses and sedges.

cuneate base

Wedge-shaped; a gradually tapering leaf base that forms an angle less than 90°. See Figure 8.

cupule

A cup-shaped structure, composed of numerous small, hard, coherent bracts, that subtends the nut of an acorn; e.g. acorns, the fruit of oaks (Quercus), are composed of a nut (calybium) and a cap (cupule).

cuspidate

Ending in a short point, or cusp; usually referring to a leaf apex. See Figure 7.

cyathium

The type of inflorescence characteristic of plants in the genus Euphorbia (Euphorbiaceae). A cyathium (plural: cyathia) is a very specialized structure, composed of a cup-like involucre that surrounds tiny unisexual male and female flowers that lack a perianth, the rim of the involucre bears 1-few brightly-coloured nectar glands; e.g., cypress spurge (Euphorbia cyparissias) has 4 moon-shaped (lunate) nectaries around the rim of the cyathium, which is subtended by 2 prominent yellow petal-like bracts.

cyme

A determinate inflorescence, consisting of a mature central flower subtended by a pair of younger flowers with pedicels of equal length (adj.: cymose).

cymule

A small cyme; one division of a compound cyme.

cypsela

A dry indehiscent type of achene, derived from an inferior ovary, often with a crown of bristles or thin scales; e.g., the fruits of dandelion (Taraxacum), goldenrod (Solidago), aster (Symphyotrichum), and other members of the Aster Family (Asteraceae).

deciduous

Describes woody plants that drop their leaves at the end of each year. Deciduous trees are often called broadleaf trees.

decumbent

Growing horizontally along the surface of the ground.

decurrent

Extending downward, usually referring to leaves in which the narrowed base of the leaf or petiole is fused (adnate) to the stem below the blade; e.g., the needles of yew (Taxus), have decurrent petioles.

decussate

Opposite leaves in 4 ranks, with the 2 opposite leaves of each node attached 90° from the leaves of the previous node.

deflexed

Bent or curved sharply downward; e.g., the deflexed lip of lesser roundleaf orchid (Platanthera orbiculata) flowers.

dehisce

To split open.

dehiscent fruit

Fruits that split open (dehisce) to release their seeds when ripe.

deltate

Triangular, a 2-dimensional shape with a broad, straight base and straight sides tapering to the apex; often called deltoid in older texts. See Figure 6.

dentate

Toothed margins with pointed teeth directed outward; the teeth are oriented perpendicular to the leaf margin. See Figure 9.

denticidal capsule

A capsule that dehisces apically, forming 5-10 teeth, e.g., the capsules of chickweed (Cerastium, Caryophyllaceae).

denticulate

Finely dentate; with small pointed teeth directed outward. See Figure 9.

depressed globose

Spherical, but slightly wider than long; usually used to describe the shape of fruits; e.g., some rose hips (Rosa rugosa hips).

determinate inflorescence

An inflorescence with the terminal or central flower maturing first; growth of the axis of the inflorescence is therefore stopped; new flowers are produced below the central flower. Cymes are examples of determinate inflorescences. See Figure 16.

determinate shoot

In clubmosses, a shoot that dies after several years of sporulation.

diadelphous

A specialized arrangement of 10 stamens, in which the filaments of 9 stamens are connate, forming a sheath that surrounds the pistil, while the 10th stamen remains separate, situated above the fused stamens. Diadelphous stamens are characteristic of the Pea Family (Fabaceae).

dichasial cyme

A compound cyme in which two opposite branches form beneath the main flower, each giving rise to new flowering axes, which produces a determinate inflorescence with paired branches. Dichasial cymes are the type of inflorescence characteristic of species in the Pink Family (Caryophyllaceae).

dichasium

A simple cyme in which a pair of opposite flowers develop beneath the main flower, each supporting a single flower. See Figure 16.

dichotomous keys

To identify an unknown species, botanists use taxonomic keys, which consist of a series of mutually exclusive statements, to determine the name of their plant. Each key consists of a series of numbered, paired statements, called couplets. The two statements in each couplet, called leads, describe different plants traits or characters (e.g.: yellow petals vs. white petals). The reader must decide which of the 2 statements best fits their plant before proceeding on to the next couplet. Successive choices are made until a name is reached. For keys in this Flora, the leads in each numbered couplet are labelled 'a' or 'b'. There are different types of keys, but the one most often used to identify plants is called a dichotomous key, since the reader must choose between only 2 statement at each step. See the Keys section of this website to download the keys to families and species.

didynamous

A stamen arrangement of 4 stamens, with 1 pair of short stamens and 1 pair of longer stamens; the characteristic arrangement of stamens in members of the Mint Family (Lamiaceae).

dimorphic

With two forms; dimorphic fern fronds have sterile and fertile fronds that are different in size and shape.

dioecious

Plants that have separate unisexual flowers on different plants.

disc florets

Small flowers that form the central portion (or all) of a capitulum, the type of inflorescence characteristic of the Aster Family (Asteraceae). Disc florets have a tubular, 5-lobed corolla with regular (actinomorphic) symmetry.

discoid head

A composite head (capitulum) composed only of disc florets; e.g., the discoid heads of Joe-Pye weed (Eutrochium maculatum).

discolorous

Describes leaf blades with upper and lower surfaces of different colours, aka: discolor; e.g., the dark green upper surface and glaucous lower surface of pussy willow (Salix discolor) leaves.

discrete

Individual, separate and distinct.

dissected

With narrow divisions, each finely subdivided into many smaller segments. See Figure 9.

distichous

With 2-ranked leaves; alternate leaves arranged on opposite sides of a stem.

divergent

A leaf apex or base with short, straight-sided lobes directed outward. See Figure 8.

divided

Leaf margins with pointed lobes and deep indentations cut ¾ or nearly to the midrib.

double-serrate

Serrate, with each large tooth divided into two or more smaller teeth. See Figure 9.

drupe

A fleshy, simple, indehiscent fruit with a thin exocarp (skin), a fleshy or fibrous mesocarp, and a single, stony endocarp (the pit or stone), which surrounds the seed or seeds; e.g., the fruit of northern wild raisin (Viburnum cassinoides), bunchberry and dogwood (Cornus), and cherries (Prunus).

drupelet

A small drupe, usually one segment of an aggregate fruit (drupecetum).

drupetum

An aggregate of drupelets; e.g., the fruits of raspberries, blackberries, or bakeapple (Rubus spp.); formerly spelled 'drupecetum' (Spjut 1994).

dry fruit

A fruit with a dry or woody pericarp, which may be rather thin and easy to break, or hard and stony.

dwarf shrubs

Low, woody, often creeping plants, to 25 cm tall; dwarf shrubs are also known as chamaephytes and have overwintering buds borne close to the ground.

echinate

The short-spiny surface of some fruit; e.g., the surface of nutlets of wild comfrey (Andersonglossum boreale).

eligulate

Lacking ligules.

elliptic

A 2-dimensional shape, widest at the middle, with curved sides and a tapering base and apex. See Figure 6.

emarginate

With a shallow notch at the apex of a leaf blade. See Figure 7.

emergent

Plants rooted in standing water (ponds or streams), but with leaves growing upward above the surface of the water.

endemic

Having a natural geographic range restricted to a defined area; e.g., Newfoundland chickweed (Cerastium terrae-novae) is endemic to insular Newfoundland.

endocarp

The inner layer of the fruit wall; the hard pit of a peach or cherry is the endocarp, which surrounds the seed.

endosperm

The triploid food reserve in a seed, derived from fusion of the polar nuclei with a sperm nucleus.

endozoochory

Dispersal of fruits or seeds by animals, involving ingestion and defecation (adj.: endozoochorous).

ensiform

Sword-shaped, gradually tapering to the apex.

entire

A smooth edge or leaf margin with no indentations. See Figure 9.

entomophily

Pollination by insects (adj.: entomophilous).

epaleate

Composite heads (capitula) that lack paleae (bractlets that subtend florets) on the receptacle.

epicalyx

An extra set of bract attached to the lower surface of a calyx, alternate with the calyx lobes; characteristic of some plants in the Rose (Rosaceae) or Mallow (Malvaceae) Families.

epigynous

A flower type in which the ovary is situated below the attachment of the stamens, petals, and sepals; the calyx tube is fused to the wall of the inferior ovary in epigynous flowers. See Figure 12.

epizoochory

Dispersal of fruits or seeds by attachment to the fur of animals or the clothing of humans (adj.: epizoochorous).

equitant

Basal leaves that are 2-ranked, with overlapping bases; the leaves are sharply folded along the midrib at the base, but become flattened upwards in one plane. New leaves emerge from between the bases of the previous leaf; e.g., the leaves of blueflag (Iris versicolor).

ericaceous

(adj.) Describes shrubs that belong to the Blueberry Family (Ericaceae).

erose

With margins that appear gnawed, with irregular, shallow indentations. See Figure 9.

eusporangium

A sporangium with a sporangial wall more than 2 cell layers thick and lacking a distinct annulus (plural: eusporangia); the type of sporangium characteristic of moonworts (Ophioglossaceae) and more primitive fern species; originating from a group of embryonic cells, called initial cells. See also: leptosporangium.

evergreen

Describes plants that retain their leaves or needles throughout the year. Most evergreen plants are coniferous trees or shrubs, but a few herbaceous plants have leaves that are evergreen.

exocarp

The outer layer of the fruit wall; the skin of a fruit.

exserted

Extending above or beyond a subtending structure, as in stamens that are exserted beyond a corolla; e.g., the exserted stamens in smooth gooseberry (Ribes hirtellum) flowers.

exstipulate

Leaves that lack stipules.

extrorse

Anthers that dehisce outwards, away from the centre of the flower and the pistil; e.g., the extrorse anthers of bluebead lily (Clintonia borealis).

falcate

Sickle-shaped, curved; e.g., the pinnae of Christmas fern (Polystichum acrostichoides).

false berry

A simple, indehiscent, berry-like fruit derived from an inferior ovary plus the hypanthium of the floral tube that surrounds the ovary; e.g., the fruits of blueberry, cranberry, currant, gooseberry, and banana. Also known as an epigynous berry.

false indusium

An indusium produced by frond tissue that folds over a sorus, such as the marginal (false) indusium of bracken fern (Pteridium aquilinum).

fascicle

Re: inflorescences: A cluster of long-pedicelled flowers attached to the stem, with the pedicels separated by very short internodes; e.g., pin cherry (Prunus pensylvanica). Re: needles: A group of pine needles bound at the base by a sheath of papery bracts. The number of needles per fascicle is characteristic of different pine species See Figure 3. Re: stamens: A group of stamens with fused filaments, usually fused only at the base; e.g., marsh St. Johnswort (Triadenum) flowers have 9 stamens arranged in 3 fascicles of 3 stamens.

fastigiate

With erect branches arranged closely together; e.g., Lombardy poplar (Populus nigra subsp. italica) trees have a fastigiate form.

fern

A vascular plant with a dominant sporophyte (spore-producing) generation; fern leaves (fronds) are usually divided into pinnae, which may be further divided once or twice into smaller units called pinnules; spores are produced in sporangia borne on separate fronds or pinnae, or in clusters on the lower surface of the fronds.

ferruginous

Rusty-coloured, usually referring to the colour of hairs on leaves.

fibrillose

Breaking down into individual fibers; referring to the basal sheaths of sedge leaves.

fibrous roots

Roots that branch repeatedly in the soil, forming a mass of slender roots. Compare to taproot.

filament

A stalk that supports the anther of a stamen. See Figure 11.

filiform

Thread-like, very slender.

fimbriate

fringed along the margin; e.g., the fringed lips of some orchids, or the fringed stipules of the Japanese rose (Rosa multiflora).

flabellate

Fan-shaped (or flabelliform).

flabellate

Fan-shaped. See Figure 6.

flaccid

Referring to aquatic plants: limp, weak; unable to stand erect when removed from the water.

fleshy fruit

A fruit with a thin exocarp (skin) surrounding the fleshy mesocarp and/or endocarp.

floccose

A type of pubescence, bearing tufts of woolly hairs that usually fall off as the leaves mature.

flocculent

A type of pubescence, with small, loose tufts or fluffy patches of soft, tangled, woolly hairs.

floret

A single, small flower of certain compound inflorescences, such as the capitulum (head) of asters (Asteraceae) or the spikelets of grasses and sedges (Poaceae, Cyperaceae).

floricane

The second-year flowering cane of raspberry and blackberry (Rubus) plants.

flower

The reproductive organ of angiosperms (flowering plants). See Figures 11, 12.

foliaceous

Leaf-like.

follicetum

An aggregate of follicles; e.g., columbine (Aquilegia), marsh marigold (Caltha palustris), and magnolia (Magnolia) flowers have separate pistils in each flower that develop into follicles; collectively the several follicles of each flowers comprise a follicetum.

follicle

A dry, dehiscent fruit derived from an ovary with 1 carpel that dehisces along one line; e.g., milkweed (Asclepias syriaca) pods are actually follicles.

forb

Herbaceous plants that produce flowers, often with showy petals; excluding grass-like (graminoid) families.

fragmentation

A type of asexual reproduction in which a severed branch takes root and develops into a new shrub or tree.

fringe

The incised margin of a petal or sepal; e.g., the fringed lip of the ragged fringed orchid (Platanthera lacera).

frond

The leaf of a fern.

frugivorous

Fruit-eating, describing birds or mammals that eat fruit.

fruit

A mature ovary and associated floral parts.

fugacious

Lasting for a short time, ephemeral; e.g., the fugacious basal leaves of Alaskan rein orchid (Platanthera unalascensis) plants usually wither before the flowers bloom.

functionally unisexual

Unisexual flowers that possess both male and female organs, but only one sex is fertile; the organs of the non functioning sex are noticeably smaller. Some dioecious plants, such as wild sarsaparilla (Aralia nudicaulis), have functionally unisexual flowers.

funiculus

The stalk of a seed, which attaches an ovule to the placenta in the ovary or fruit.

funnelform

Funnel-shaped, a corolla with a narrow base and sides that flare outward; e.g., the funnelform corolla of hedge bindweed (Calystegia sepium) flowers.

fuscous

Dark greyish-brown in colour, dusky, swarthy.

galea

The upper hood-like or helmet-like lip of a 2-lipped corolla; e.g., the upper lip of marsh lousewort (Pedicularis palustris) and northern paintbrush (Castilleja septentrionalis) flowers.

gemmae

Vegetative propagules characteristic of the firmoss genus Huperzia (Lycopodiaceae).

gemmiferous branches

Short lateral branches on which gemmae are produced; found in lycophyte plants of the genus Huperzia.

generalist pollination

A type of pollination, found in plant species that often have open, bowl-shaped flowers with unspecialized stamens and pistils; these flower types are accessible to and capable of being pollinated by a variety of pollinators. Generalist pollinators, usually insect species, will visit and potentially pollinate the flowers of a wide variety of species.

genet

A clone or colony of genetically identical individuals. Compare to 'ramet'.

geniculate

Bent at a sharp angle, like a bent knee.

gibbous

An asymmetric corolla with a convex bulge near the base; e.g., the gibbous corolla of honeysuckle (Lonicera villosa) flowers.

girdled

Encircling.

glabrate

Initially hairy, but becoming glabrous (smooth) at maturity.

glabrescent

Becoming nearly glabrous, with a few scattered hairs remaining on the leaf surface at maturity.

glabrous

Smooth; lacking hairs.

glandular

Bearing glands; glandular stems or leaves are often sticky to the touch.

glandular-pubescent

Bearing glandular hairs.

glans

An accessory fruit, composed of a nut (calybium) derived from an inferior ovary, and subtended by a scaly, cup-like involucre (cupule); commonly called an 'acorn', e.g., the fruit of oaks (Quercus, Fagaceae).

glaucous

A surface with a pale gray, bluish-green, or bluish-white waxy coating (bloom); similar to pruinose.

globose

A 3-dimensional spherical shape, globe-shaped; aka: globular.

glomerule

A small cluster of sessile or short-pedicelled flowers; e.g., flowers of hawthorns (Crataegus) occur in glomerules.

glume

A modified bract, usually occurring in pairs (or singly), which subtends a grass spikelet composed of one or more florets.

glutinous

Sticky or gummy; usually referring to a coating of sticky sap; e.g., the glutinous buds of showy mountain ash (Sorbus decora).

gradually tapering

Describes a leaf that tapers or narrows evenly to the base or apex.

graminoid

Herbaceous plants that belong to the Grass (Poaceae), Sedge (Cyperaceae), or Rush (Juncaceae) Families. Graminoid species have small, inconspicuous, and highly modified flowers that lack showy perianth parts.

gymnosperms

Vascular plants that lack flowers and produce seeds on scales in woody cones. Gymnosperms are commonly called coniferous plants (conifers) or cone-bearing plants. Gymnosperm leaves, called needles, may be long and narrow (as in pines) or short and scaly (as in cedar). Most gymnosperms are evergreen, retaining their needles throughout the year. Some gymnosperms, like larch (Larix laricina), drop their needles each year.

gynecandrous

Bisexual Carex spikes with staminate flowers situated below the pistillate flowers in the same spike. See also 'androgynous'.

gynoecium

A collective term for all of the female structures of a flower.

halophile

A plant able to tolerate soils with a high salt content; aka: a halophilic plant or halophyte.

halophilic

Salt-loving; preferring saline soils (adj.: halophilous).

hastate

Halberd-shaped; a 2-dimensional shape with a pointed apex and two triangular basal lobes pointed outward. See Figure 6.

hastate base

A leaf base with two triangular basal lobes that point outward. See Figure 8.

haustorium

The modified root of a parasitic plant, adapted to obtain nutrients from a host plant (plural: haustoria).

head

See 'capitulum'.

helicoid cyme

A determinate inflorescence (monochasial cyme) in which new flowers develop only on one side of successive flower pedicels, producing an arching or recurved flowering axis; e.g., sundews (Drosera) flowers are arranged in a helicoid cyme. Also called a bostryx. Compare to 'scorpioid cyme'. See Figure 16.

hemiamphistomatic

Having stomates on both leaf blade surfaces, but with stomates distributed evenly only across the lower blade surface; stomates on the upper blade surface occur along the main veins and at the apex (adj.: hemiamphistomatous). A term used primarily in reference to willow (Salix) leaves. See also 'amphistomatic' and 'hypostomatic'.

hemiparasite

Partially parasitic plants, capable of producing their own food through photosynthesis, but also obtaining food from a host plant; e.g., yellow rattle (Rhinanthus) plants are hemiparasitic.

herb

A flowering plant that lacks woody stems and dies back to the ground at the end of the growing season. The term herb includes both forbs and graminoids. In a culinary sense, herbs are seasonings derived from fresh or dried leaves.

herbaceous

Describes plants or plant parts that lack woody tissue.

hermaphroditic

Flowers that posses both male and female fertile organs.

heterosporous

Lower vascular plants that produce spores of two types – larger megaspores that develop into female gametophytes, and smaller microspores that develop into male gametophytes.

heterotrophic

Organisms that cannot make their own food; they ingest food from an outside source.

hip

A fleshy, indehiscent, accessory fruit derived from the hypanthium and receptacle of a rose (Rosa) flower. Rose hips surround and enclose the achenes as the fruit develops. The achenes within a rose hip are the true fruits of the rose.

hirsute

A type of pubescence; bearing short coarse or stiff hairs.

hispid

A type of pubescence; bearing long rigid hairs or slender bristles.

hoary

A type of pubescence; appearing greyish-white, as in hoar frost, due to the presence of soft dense pale grey or white hairs; also called 'canescent'; e.g., leaves of the hoary willow (Salix candida).

holoparasite

Plants that obtain all of their nutrients directly from a host plant by means of modified roots called haustoria; a holoparasite is also called an obligate parasite.

homosporous

Lower vascular plants that have only one type of spores, all of similar size and shape.

hyaline

Translucent or nearly transparent.

hymenopterophily

Pollination by winged insects (Hymenoptera), including bees, wasps, and flies, etc. (adj.: hymenopterophilous).

hypanthial disk

A flat, circular disk on the top of a hypanthium, formed by the fusion of the bases of numerous stamens in epigynous flowers. In roses (Rosa), the styles of the numerous inferior ovaries extend beyond the hypanthial disk through a small circular opening, called the stylar orifice.

hypanthium

A cup-shaped expansion of the receptacle that surrounds the pistil (or pistils) in certain flowers. The hypanthium may be free from or fused to the ovary.

hypogynous

A flower type with a superior ovary, in which the ovary is situated above the attachment of the stamens, petals, and sepals to the receptacle. See Figure 12.

hypostomatic

Having stomates only on the lower leaf blade surface, with the stomates distributed evenly across the lower blade surface (adj.: hypostomatous). A term used primarily in reference to willow (Salix) leaves. See also 'amphistomatic' and 'hemiamphistomatic'.

Hypsithermal Period

A period of relatively warmer temperatures experienced in northern latitudes between 9000 to 5000 years ago; also known as the Holocene Climate Optimum.

imbricate

With overlapping bases; the older layer of leaves or scales overlap the younger structures.

imbricate scales

Bud scales that overlap.

impressed

Depressed below the surface, recessed; referring to veins that appear as ridges along the lower surface of rugose leaves; e.g., leaves of balsam willow (Salix pyrifolia).

incised

An irregular margin with sharp, jagged, deep cuts. See Figure 9.

indehiscent fruit

Fruits that remain closed and only release their ripe seeds through physical breakdown or decomposition of the fruit.

indeterminate inflorescence

An inflorescence with the lower (or lateral) flowers maturing first; growth of the inflorescence continues upward (or outward) as the axis of the inflorescence elongates (or broadens). See Figure 15.

indeterminate shoot

A shoot that can grow upwards (apically) indefinitely, at least until the end of the growing season. An indeterminate inflorescence has the oldest (first opening) flowers at the base, with new flowers forming at the top of the inflorescence.

indicator species

Plants that individually, or in groups, can be used to identify the ecological conditions of a site. For example, dwarf raspberry (Rubus pubescens) is a good indicator of nutrient-rich sites; sheep laurel (Kalmia angustifolia) indicates nutrient-poor sites/ and mountain avens (Dryas integrifolia) indicates the presence of limestone bedrock.

indusium

A sterile flap of tissue that covers the developing sporangium of a fern sorus (plural: indusia).

inferior ovary

An ovary situated below the attachment of the stamens, petals, and sepals in a flower. See Figure 12.

inflorescence

A cluster of flowers. See Figures 15, 16.

infrastipular

Attached below the stipules; e.g., the infrastipular prickles of Virginia rose (Rosa virginiana) are situated below the stipules.

infructescence

A cluster of fruits, derived from an inflorescence.

internodal bristles

Bristles that occur on internodes of a stem; e.g., the internodal bristles of bristly black currant (Ribes lacustre) stems.

internodal prickles

Prickles that occur on internodes, rather than the node of a stem; e.g., shining rose (Rosa nitida) stems have internodal prickles.

internode

The region of a stem between nodes; no leaves are attached along the internode. See Figure 13.

intracalycular membranes

areas of thin translucent tissue situated between the calyx lobes of some gentians; e.g., intracalycular membranes occur between the calyx lobes of narrowleaf gentian (Gentiana linearis) flowers; also called intracalycine membranes.

introrse

Anthers that dehisce inward, towards from the centre of the flower and the pistil; e.g., the introrse anthers of harebell (Campanula) flowers.

involucel

A collective term for the small bracts that subtend the umbellets of a compound umbel; a secondary level or smaller involucre. See Figure 14.

involucre

A collective term for several bracts that subtend an inflorescence, usually in a compound umbel or a head (capitulum); see Figure 14. In the Asteraceae, the involucral bracts (call phyllaries) overlap and cover the base of the inflorescence. Also referring to leafy bracts that subtend the base of a flower or fruit; e.g., the elongate involucre of beaked hazel (Corylus cornuta).

involute

With margins rolled inward on the upper surface of the leaf; e.g., the leaves of butterwort (Pinguicula vulgaris) have involute margins. See Figure 9.

jointed stems

Stems or culms that have solid nodes; e.g., horsetails (Equisetum) and grasses.

keel

A prominent central ridge or crease on the lower surface of a leaf or other structure, like the keel of a boat. In flowers of the Pea Family (Fabaceae), the two lower petals, fused (connate) along the bottom margin, are referred to as the keel.

keys

See 'dichotomous keys'.

krummholz

Dwarf, wind- or frost-pruned conifers, typically found along coastal shorelines, ravines, or alpine areas where plants are exposed to high winds.

lacerate

Leaf margins with irregular jagged indentations or divisions. See Figure 9.

ladder-fibrillose

the ladder-like arrangement of persistent fibres that remain after the hyaline sheath on sedge leaves starts to disintegrate.

lamina

The flat portion of a leaf or frond blade.

laminar

(adj.) Flat; referring to stamens with flattened filaments; e.g., the stamens of dewberry (Rubus pubescens) have laminar filaments.

lanate

A type of pubescence; bearing long intertwined woolly hairs.

lanceolate

Lance-shaped; a 2-dimensional shape, somewhat narrow, widest below the middle and tapering towards the apex; lanceolate leaves are 3-6 times as long as wide. See Figure 6.

lanceoloid

A 3-dimensional shape; lanceolate or lance-shaped in outline.

lateral buds

Buds located along the sides of a branch or twig, below the branch tip. See Figure 13.

layering

A type of asexual reproduction in which lower tree branches, in contact with the soil, root and develop upright shoots that eventually grow into individual trees.

lead

(noun) In keys to plant species, each of the two statements or choices in a couplet is called a lead. For the keys in this Flora; the two leads in each couplet are numbered as 'a' or 'b'; e.g.: 1a, 1b, 2a, 2b., 3a, 3b, etc. See also 'dichotomous keys'.

leader

The current annual growth, or growing tips, of tree branches.

leaf

The photosynthetic organ of a plant, usually with a flat blade. A simple leaf has a single, undivided leaf blade. Simple leaves may be lobed or unlobed. See Figure 1.

leaf apex

The tip or apical portion of a leaf blade (plural: leaf apices). See Figures 1, 7.

leaf axil

The angle between stem and its attached leaf.

leaf base

The lower or basal portion of a leaf blade. See Figures 1, 8.

leaf blade

The flat, expanded portion of a leaf. The leaf blade is the site of photosynthesis (food production), leaf blades may be attached to a stem directly (sessile leaves) or by a slender stalk called a petiole (petiolate leaves). See Figure 1.

leaf gap

A space in the vascular cylinder resulting from a leaf trace entering a megaphyll, leaving a gap in the vascular tissue.

leaf margins

The edges of a leaf blade.

leaf scar

A scar on a twig formed where a leaf dehisced or dropped from the stem. The shape of leaf scars is used in twig identification. See Figure 13.

leaflet

One segment of a compound leaf; leaflets may be attached directly to the rachis (sessile leaflets) or attached by a small petiolule (stalked leaflets). See Figure 2.

legume

A dry, dehiscent fruit derived from an ovary with 1 carpel that splits along 2 lines; e.g., the fruits of beans and peas; legumes are sometimes called pods, as in pea pods.

lemma

The outer bract of 2 small bracts in a grass floret; the lemma surrounds the palea, stamens, and pistil.

lenticels

Small, slightly raised, corky, dot-like, lenticular, or horizontal lines on the bark of a stem or tree trunk. Lenticels function as sites for gas exchange between the atmosphere and the internal tissues of the plant. Birch, cherry, and elderberry stems have prominent lenticels on their bark. See Figure 13.

lenticular

Lens-shaped in cross-section, with convex sides.

lepidote

Covered with small scurfy stalked (peltate) scales; e.g., Lapland rosebay (Rhododendron lapponicum) has lepidote leaves.

leptosporangium

A sporangium with the sporangial wall only 1 cell layer thick and dehiscing by means of an annulus (plural: leptosporangia); the type of sporangium characteristic of most ferns; originating from a single embryonic (initial) cell.

ligulate floret

A small flower, characterized by a short tubular base and a longer, flat, strap-like upper portion, with 5 small teeth or lobes at the apex; e.g., one flower of a capitulum (head) in wild chicory (Cichorium intybus).

ligulate head

A composite head (capitulum) containing only ligulate florets; e.g., the ligulate heads of wild chicory (Cichorium intybus).

ligule

Re: composite flowers: The flat, strap-like portion of the corolla of a ligulate floret, with 5 small teeth or lobes at the apex. Re: grasses: A small translucent flap of tissue located at the junction of the sheath and blade of a grass leaf, marking where the leaf sheath ends and the blade begins; although less prominent, ligules are also found in some sedge (Carex) species. Re: quillworts: A thin flap of tissue situated above a sporangia on the upper (adaxial) surface of a microphyll.

limb

The expanded upper portion of a petal with a clawed base.

linear

A 2-dimensional shape, long and very narrow, with nearly parallel margins; linear leaves are several to many time longer than wide. See Figure 6.

lip

The lowest central petal of 6 petals in flowers of the Orchid Family, often greatly modified.

lobed

Leaf margins with rounded projections (lobes) alternating with shallow indentation (sinuses); lobed leaves may be pinnately lobed or palmately lobed. See Figures 3, 9.

locule

The chamber or cavity within a carpel where the ovules are located.

loculicidal capsule

A capsule that dehisces through the outer wall of each locule, leaving the partitions (septae) between locules intact.

lodicule

One of 2 small flat structures found at the base of a grass flower, believed to be remnants of the perianth.

lorate

A 2-dimensional shape; linear-lanceolate or strap-like, 6 times longer than wide, and tapering to an acute or acuminate apex; usually used to describe the shape of some willow (Salix) leaves. See Figure 6.

lower vascular plants

Plants that have vascular tissue and reproduce only by spores; they lack flowers and seeds. Ferns, horsetails, and clubmosses are examples of lower vascular plants.

lunate

Shaped like a crescent moon.

lustrous

Shiny, glossy.

lycophytes

The common name of plants in the Phylum Lycopodiophyta, including clubmosses, quillworts, and spikemosses. Lycophytes include the oldest known living plants on Earth.

lyrate

Lyre-shaped; an oblanceolate shape with 2 or more pairs of small lobes towards the leaf base.

-merous

In multiples of; a 3-merous flower has sepals, petals, stamens, and carpels in multiples of 3; a 5-merous flower has parts in multiples of 5.

mafic

Rocks of volcanic origin (igneous rocks) that have a high magnesium, iron, and calcium content, such as the basalt, gabbro, and diabase. The word 'mafic' is derived from a combination of "ma…" for magnesium, and "f..ic" for ferric (iron).

marcescent

Having dry dead leaves persisting along a stem for more than one year.

margin

The edges of a leaf blade, petal, or sepal. See Figures 1, 9.

marginal indusium

A sterile flap of tissue at the margin of a fern pinnule that fold over a marginal sorus.

marginal sorus

Clusters of sporangia that develop along the margins of a fern pinnule.

mealy

A dry, granular, or powdery texture, similar in appearance to corn meal.

medial

Referring to the position of sori, situated midway between the midvein and the margin of a pinnule.

megaphyll

A leaf with more than one strand of vascular tissue, variously branched, and associated with a leaf gap in the vascular tissue in a stem; the type of leaf characteristic of ferns, gymnosperms, and angiosperms.

melittophily

Pollination by bees (adj.: melittophilous).

membranaceous

A thin membrane-like texture, usually used to describe the texture of leaves.

mentum

A protruding chin-like structure in orchid flowers, formed by the fusion of the column base and the 2 lateral sepals.

mericarp

One half of a schizocarp, the fruit type characteristic of plants in the carrot family (Apiaceae).

mesocarp

The middle layer of the fruit wall; the fleshy part of a peach is the mesocarp.

microphyll

A small leaf with a single unbranched vascular strand, characteristic of lower vascular plants, such as lycophytes; stems with microphylls do not have leaf gaps.

midrib

The central vascular strand or primary vein of a leaf or leaflet, also called the midvein. See Figures 1, 2.

monadelphous

A stamen arrangement in which all of filaments are connate around the style, while the anthers remain free; e.g. the monadelphous stamens of musk mallow (Malva moschata).

monochasium

A cyme in which flowering branches develop on only one side of the flowering axis, below the terminal flower; this is caused by the abortion of the opposite bud of the cyme and produces an elongate cyme. Also described as a monochasial cyme. When branching in a monochasium always occurs on the same side of the flowering axis, a helicoid cyme is produced; when branching in a monochasium always occurs on alternate sides of the flowering axis, a scorpioid cyme is produced.

monoecious

A plant with separate male and female unisexual flowers on the same plant.

monomorphic

With one form; monomorphic fern fronds have sterile and fertile fronds that are similar in size and shape.

monopodial rhizomes

Horizontal, creeping rhizomes in which the terminal bud produces new apical growth of the rhizome, while lateral buds on the rhizome produce aerial shoots. New plants from monopodial rhizomes usually occur in a straight line. Compare to 'sympodial rhizomes'.

mucronate

A leaf apex ending in an abrupt short point, formed by a short extension of the midrib beyond the leaf blade. See Figure 7.

multiple fruit

A type of fruit derived from an entire inflorescence; the individual ovaries fuse tightly together into a single unit as the fruit develops; e.g., a pineapple.

mycotrophic

Plants that obtain nutrients indirectly through a mycorrhizal association with the roots of a host plant.

myrmecochory

Dispersal of fruits or seeds by ants; e.g., the seeds of violets (Viola).

naked sorus

A cluster of sporangia not covered by an indusium.

nectariferous

Producing nectar.

nectary

A gland that secrets nectar.

needle

A gymnosperm leaf; needles may be long and narrow (as in pines) or short and scaly (as in creeping juniper).

net venation

An arrangement of veins in which many small (tertiary) veins form a network between the secondary veins; also called reticulate venation. See Figure 10.

nitrophile

A plant that prefers nitrogen-rich soils; aka: nitrophyte.

nitrophilic

Nitrogen-loving; preferring nitrogen-rich soils; (adj.: nitrophilous.

nodal spines

Spines that occur at the nodes of a stem; e.g., smooth gooseberry (Ribes hirtellum) stems bear nodal spines.

node

The region of a stem where leaves or buds are attached. See Figure 13.

non-vascular plants

Primitive plants that lack thick-walled vascular tissues in their stems. Mosses and liverworts are examples of non-vascular plants.

nut

A type of hard, indehiscent, 1-seeded fruit with a hard bony bony fruit wall (pericarp), derived from a superior ovary with 1 locule; sometimes surrounded by a papery or spiny involucre; e.g., beaked hazel (Corylus cornuta) nuts are enclosed within an beak-like involucre.

nutlet

A small nut-like fruit, often occurring in pairs or 4s; e.g., the fruits of alder (Alnus) or mint (Mentha).

obclavate

Inversely club-shaped or clavate, with a rounded base and tapering gradually to the apex.

obconical

Inversely cone-shaped, with the pointed part at the base and the broad part at the apex.

obcordate

Inversely heart-shaped; a 2-dimensional shape, basically obovate, but with 2 rounded apical lobes and a cuneate base. See Figure 7.

oblanceolate

Inversely lance-shaped; a 2-dimensional shape, narrow and widest above the middle, with a rounded to blunt apex and tapering gradually to the base. See Figure 6.

oblanceoloid

Inversely lance-shaped; a 3-dimensional shape, narrow and widest above the middle, with a rounded to blunt apex, gradually narrowing to the base.

obligate outcrosser

A plant species with flowers that are self-incompatible and must be cross-pollinated by pollen from plants of a different individual or clone in order to achieve fertilization and successful fruit and seed set.

oblique base

A leaf base with asymmetrical sides of unequal size and attached to the midrib at slightly different points. See Figures 3, 8.

oblong

Rectangular; a 2-dimensional shape with nearly parallel sides, about 2 to 3 times as long as wide. See Figure 6.

obovate

Inversely ovate; a 2-dimensional shape, broad and widest above the middle, tapering gradually to the base. See Figure 6.

obovoid

Inversely ovoid; a 3-dimensional shape, broad and widest above the middle.

obtrullate

A 2-dimensional shape; resembling a kite, with the broadest axis above the middle and a length to width ratio between 3:2 and 2:1. See Figure 6.

obtuse

A blunt apex (or base) that forms an angle greater than 90°. See Figures 7, 8.

ochrea

A translucent sheath that surrounds a stem above each node, formed by fusion of a pair of connate stipules (adj.: ochreate); e.g. ochrea are characteristic of species in the Buckwheat Family (Polygonaceae).

operculate capsule

A capsule that dehisces by means of pores that are covered by a flap or lid (operculum); e.g., poppies (Papaver) have operculate capsules.

opposite

A leaf arrangement with pairs of leaves attached on opposite sides of each node. See Figure 4.

orbicular

Circular in outline; a 2-dimensional shape with rounded margins throughout. See Figure 6.

oval

A 2-dimensional shape, widest at the middle, with convex sides and a rounded base and apex. See Figure 6.

ovary

The portion of the pistil that contains the developing seeds; the ovary wall develops into the fruit. See Figure 11.

ovate

Broadly spear-shaped; a 2-dimensional shape, widest below the middle and tapering towards the apex; ovate leaves are up to twice as long as wide. See Figure 6.

ovoid

A 3-dimensional ovate shape, similar to the outline of an egg.

ovules

Embryonic seeds, contained within the ovary of a flower; the ovules develop into seeds within the fruit.

palate

An enlarged portion of the lower lip of a bilabiate corolla, which protrudes into the throat of the corolla.

palea

Re: composite flowers: A small bract on the receptacle of a composite flower that subtends an individual floret (adj.: paleate). Re: grass florets: The small inner bract of 2 bracts that subtend a grass floret; the palea encloses the stamens and pistil of grass florets.

palmate venation

A type of net venation in which 3 or more primary veins arise from one point (top of the petiole) and extend into individual lobes of the leaf. See Figure 10.

palmately compound

A compound leaf with all of the leaflets attached at one point at the top of the petiole; there is no rachis in a palmately compound leaf. See Figure 2.

palmatifid

Palmately divided; with lobes all arising from the base of the leaf. See Figure 9.

pandurate

Fiddle-shaped; a 2-dimensional shape, oblong to oval, and narrowed at the middle; e.g., the pandurate lip of hooded ladies-tresses (Spiranthes romanzoffiana) flowers. See Figure 6.

panicle

An indeterminate, branched inflorescence with each of the branches divided further into secondary branches. See Figure 15.

paniculate

Panicle-like, arranged like a panicle.

papilionaceous

The type of flower characteristic of plants in the Pea Family (Fabaceae), consisting of an upper 'banner' petal, 2 lateral 'wing' petals, and a lower 'keel' petal, formed by the fusion of the lower margin of 2 petals; the keel surrounds the stamens and pistil.

papillae

Slender fleshy hair-like projections on the lip of some orchids; e.g., dragon’s mouth (Arethusa tuberosa).

papillose

Bearing small papillae (fleshy projections) on the surface.

pappus

The highly modified calyx of flowers in the Asteraceae, situated at the top of the fruit (achene), in the form of scales, hairs, persistent bristles, or awns.

parallel venation

An arrangement of veins in which a series of relatively parallel veins extends from the base to the apex of a leaf. See Figure 10.

parasitic

Deriving nutrition from a host plant.

parted

A leaf that has incisions cut ½ to ¾ of the distance to the midrib; leaves may be pinnately or palmately parted.

pectinate

Pinnately divided, resembling the divisions of a feather. See Figure 9.

pedicel

A small stalk attaching individual flowers to the axis (rachis) of an inflorescence. See Figures 11, 14.

pedicellate

Describes flowers attached by a small stalk (pedicel) to the main axis of an inflorescence.

peduncle

The stalk of a single flower, or of an entire inflorescence. See Figures 11, 14.

peltate

A type of attachment, in which the petiole is attached to the lower surface of the leaf blade. See Figure 5.

peltate scales

Tiny scales attached to a stem or bud by a stalk originating from the centre of the scale's lower surface, similar to a short umbrella.

penicillate

a feathery stigma, composed of a tuft of fine hairs; e.g., the penicillate stigmas of arrowgrass (Triglochin) flowers.

perennial

A plant (or shoot, if stems are subterranean) that lives for 3 or more year, with the potential to reproduce annually.

perfoliate

A leaf in which the leaf bases surround and fuse around the stem, forming a leaf in which the stem appears to go through the leaf blade. See Figure 5.

perianth

A collective term referring to all of the petals and sepals of a flower. See Figure 11.

pericarp

The fruit wall, composed of 3 layers: the outer exocarp, the middle mesocarp, and the inner endocarp.

perigynium

A modified papery bract that surrounds the ovary (or achene) of Carex flowers (or fruit).

perigynous

A flower type with a calyx tube (hypanthium) surrounding a superior ovary, but not fused to the ovary; calyx lobes, petals, and stamens are attached at the rim of the hypanthium. See Figure 12.

persistent

Remaining attached for a period of time after the function of the original structure has ended; e.g., fruits that are persistent throughout winter, rather than dropping off at the end of the growing season, or the persistent dried corolla at the end of current and gooseberry (Ribes) fruits.

personate

A 2-lipped corolla, with the upper lip arching over the lower lip, which has an enlarged palate protruding into the throat of the corolla; e.g., the flowers of butter-and-eggs (Linaria vulgaris) have a personate yellow corolla with an orange palate.

petal

One part of the inner whorl of floral parts, often brightly coloured to attract pollinators. See Figure 11.

petaloid

Petal-like.

petaloid sepals

Sepals that are similar in colour and shape to the petals and appear more like petals than sepals; the 3 sepals of bluebead lily (Clintonia borealis) flowers are all petaloid.

petaloid styles

Styles that look like petals; the petaloid styles of blueflag (Iris versicolor) flowers.

petaloid tepals

Perianth parts (petals and sepals) that are all similar and appear more like petals than sepals.

petiolate

Describes a leaf that has a petiole, as opposed to a sessile leaf. See Figure 5.

petiole

The narrow stalk of a leaf that attaches the leaf to a stem. See Figures 1, 2 .

petiolulate

Describes a leaf that has petiolules (stalked leaflets), as opposed to leaflets that are sessile.

petiolule

The small stalk or petiole of a leaflet, attaching the leaflets to the rachis of a compound leaf; the diminutive form of petiole. See Figure 2.

phloem

The food-transporting system of cells in a plant’s vascular tissue, which transports food (e.g., sugars) produced in the leaves to other parts of the plant.

phyllary

One of several overlapping bracts of an involucre, characteristic of flowers in the Aster Family (Asteraceae).

phyllodia

The broad, flat petioles of submerged, bladeless leaves, which serve the function of leaf blades (adj.: phyllodial); e.g., the leaves of grassleaf arrowhead (Sagittaria graminea).

phyllopodic

Fertile stems of Carex plants that bear leaves with leaf blades, as well as basal sheaths; the base of phyllopodic stems is usually surrounded by the decaying leaves of the previous year. Phyllopodic stems originate from the apical meristem of perennial vegetative shoots.

phyllotaxy

The arrangement of leaves on an axis (stem).

pilose

A type of pubescence; bearing long, soft, straight hairs oriented ± perpendicular to the surface of the stem.

pilose-hirsute

A type of pubescence, bearing long soft hairs intergrading to, or with straight bristle-like hairs.

pinna

The first level subdivision of a fern frond (plural: pinnae).

pinnate

A compound leaf, the blade divided once into leaflets organized in a pinnate fashion, with leaflets paired along a single rachis; also a fern frond, subdivided once into pairs of pinnae along a single rachis.

pinnate venation

A type of net venation in which the secondary veins are attached along the length of the midrib, and are relatively straight and parallel to each other. See Figure 10.

pinnately compound

A compound leaf with leaflets arranged in pairs along the rachis. See Figure 2.

pinnate-pinnatifid

A pinnately divided frond with the upper portion pinnatifid.

pinnatifid

Pinnately divided; with lobes arranged on opposite sides of the midrib. See Figure 9.

pinnatisect

Pinnately divided almost to the rachis, but not completely.

pinnule

The subdivisions of a fern pinna.

pioneer species

Plants that are particularly well adapted to invade habitats with bare soils and initiate primary succession after glaciation, or early secondary succession, where severe disturbance has removed the organic layer and exposed bare mineral soil. Many of these species are unique in their ability to fix atmospheric nitrogen and make it available for plant uptake.

pistil

The female reproductive organ of a flower; a pistil is composed of an ovary, a style, and a stigma. See Figure 11.

pistillate flowers

Flowers that contain only female reproductive organs; also called carpellate flowers.

pistillate scales

Small modified bracts that subtend female flowers in Carex spikes.

pistillate spikes

Spikes composed of all female (pistillate) flowers.

pith

Soft, spongy tissues in the centre of a woody stem. The colour and size of the pith is often used to distinguish between similar woody species.

pithy

A dry spongy texture, not succulent; the flesh of some fruit has a pithy texture.

plano-convex

A 3-dimensional shape; flat on one side, convex on the opposite side; usually used in reference to the shape of sedge achenes or other fruit types.

plicate

Pleated or folded repeatedly, usually referring to leaf blades; e.g., the plicate leaves of fairy slipper orchids, Calypso bulbosa).

plumose

Featherlike, usually referring to hairs or persistent styles; e.g., the plumose achenes of mountain avens (Dryas).

pollinarium

A collective term in orchids for the pollination unit transported by pollinators; composed of the pollinia, viscidium (sticky pad), and associated stalks.

pollinium

A mass of pollen grains that are dispersed as a single unit (plural: pollinia). Pollinia usually occur in pairs (in our species), rarely as a single pollinium; pollen masses in pollinia will be waxy, mealy, or powdery, depending on the genus. Pollinia are characteristic of flowers in the Orchid Family (Orchidaceae) and of milkweed (Asclepias, Apocynaceae) flowers.

polygamo-dioecious

Plants that bear unisexual flowers on separate plants as well as some bisexual flowers.

pome

A fleshy, indehiscent, accessory fruit, derived from the hypanthium and receptacle, which fuse with the ovary as the fruit develops. The fleshy part of a pome is composed of hypanthium and ovary (exocarp and mesocarp) tissue, while the endocarp forms a cartilaginous 'core' around the seeds; e.g., chuckleypear, hawthorn, apple, and pear fruits are pomes, a fruit type characteristic of the Rose Family (Rosaceae).

poricidal anthers

Anthers that dehisce by means of terminal pores or slits.

poricidal capsule

A capsule that dehisces through open pores.

porrect

Extending forward and outward; e.g., the lateral lobes of pistillate scales in heartleaf birch (Betula cordifolia) are porrect.

precocious

Early blooming; with flowers that bloom before the leaves emerge, e.g. the precocious flowers of red maple (Acer rubrum) and pussy willow (Salix discolor). See also 'coetaneous' and 'serotinous'.

prickle

A stiff, sharply pointed outgrowth of the epidermis; prickles may have a broad or narrow base, and may be recurved, hooked, or straight; e.g., prickles are common on rose (Rosa) stems; prickles lack vascular tissue and are never associated with buds.

pricklets

Small prickles on the lower surface of leaf petioles and rachises; usually on rose (Rosa) or blackberry (Rubus) leaves.

primocane

The first-year vegetative canes of raspberry or blackberry (Rubus) plants.

prophyll

A small bract (bracteole), occurring in pairs, that subtends the flowers of some rush (Juncus) species.

prophyllate

Having prophylls.

protandrous

Flowers in which the male sexual parts mature first and the stigma is receptive to pollen after anthers of the same flower shed pollen, thus facilitating self pollination. See also 'protogynous'.

protogynous

Flowers in which the female sexual parts mature first and the stigma is receptive to pollen before anthers of the same flower shed pollen, thus preventing self pollination. See also 'protandrous'.

pruinose

A surface with a powdery or dusty whitish bloom, appearing frosted; similar to glaucous; e.g., the stems or wild red raspberry (Rubus idaeus subsp. strigosus) are often pruinose.

pseudanthium

A false flower, composed of several small flowers, arranged in a central cluster and subtended by a few petaloid bracts; e.g., a bunchberry (Cornus canadensis) 'flower', with its 4 white bracts, is actually a pseudanthium; the true flowers are in the centre of the pseudanthium.

pseudocarp

A fleshy, indehiscent fruit derived from the enlarged receptacle of a flower, with numerous, small achenes embedded on the surface; e.g., a strawberry (Fragaria) fruit. The small seed-like achenes are the true fruits of a strawberry.

pseudodrupe

A type of dry, accessory fruit; with an indehiscent husk formed by an involucre fused to the outer layers (exocarp and mesocarp) of the fruit, with the hard, inner fruit layer (endocarp) surrounding the seed; the fruit of black walnut (Juglans nigra. Compare to 'drupe' and 'tryma'.

pseudoterminal bud

A lateral bud located at the tip of a branch or twig, which takes on the function of a terminal bud; pseudoterminal buds are subtended by a leaf scar, while true terminal buds are not associated with leaf scars; e.g., twigs of blueberry (Vaccinium) species have pseudoterminal buds.

pseudowhorl

A false whorl, with structures organized in tight spirals that appear as whorls.

pteridophyte

Vascular plants the reproduce by spores, such as ferns, horsetails, clubmosses, spikemosses, and quillworts.

puberulent

Very finely or minutely hairy.

pubescent

Hairy; the word 'pubescent' (or 'pubescence') is used in the general sense to describe any type and density of hairiness.

puckered

Closely undulate or ruffled; e.g., the puckered margins of the lip of hooded ladies-tresses (Spiranthes romanzoffiana) flowers.

punctate

Dotted with small glands or shallow pits.

puncticulate

Minutely punctate or dotted.

pyramidal

Pyramid-shaped; usually referring to inflorescence shapes.

pyrene

The individual stony pits of a drupe, each pyrene containing a single seed; e.g., the fruit of winterberry (Ilex verticillata) and northern wild raisin (Viburnum cassinoides). In some references, the word pyrene is also used to describe a drupe-like fruit with several small stony pits. A true drupe has a single pit, composed of a single seed surrounded by a stony endocarp.

pyriform

Pear-shaped; e.g., the ovaries and capsules of some willow (Salix) species are pyriform, wider at the bottom and abruptly narrowed above.

pyxis

The technical name for a capsule that dehisces around the circumference of the fruit (plural: pyxides); e.g., the fruit of plantain (Plantago) is a pyxis, which has circumscissile dehiscence.

-ranked

Arranged in vertical rows, such as 4-ranked leaves.

raceme

An elongate inflorescence with each flower attached to the axis of the inflorescence by a short stalk (pedicel); (adj.: racemose). See Figure 15.

racemiform cyme

A determinate inflorescence (an elongate compound cymes) that looks similar to a raceme, but the uppermost flower of the inflorescence is the oldest. In comparison, racemes are indeterminate and the uppermost flower of the inflorescence is the youngest, with growth occurring vertically.

racemose spike

A spike composed of flowers with a slender sessile ovary that resembles a pedicel.

rachis

The main axis of a compound leaf (above the petiole), a fern frond (above the stipe), or an inflorescence (above the peduncle). See Figures 2, 14.

radiate head

A composite head (capitulum) with central disc florets surround by a peripheral ring of ray florets; e.g., the radiate heads of oxeye daisy (Leucanthemum vulgare).

ramet

One individual of a clone; genetically identical to the parent plant; e.g., new trees that developed from layering of black spruce boughs are ramets of the parent tree.

ray

The primary branches of a compound umbel, each terminating in an umbellet. See Figure 14.

ray floret

A small flower with irregular (zygomorphic) symmetry, composed of a corolla of 5 fused petals, with a short tubular base, splitting along one side and terminating in a flat strap-like upper portion; ray florets are arranged around the margin of a radiate composite head; i.e., the ray florets in ox-eye daisy (Leucanthemum vulgare) are often mistaken for petals, but each 'petal-like' structure is actually a ray floret.

receptacle

The sterile base of a flower, to which the perianth parts and reproductive organs are attached. See Figure 11.

regeneration

In forestry, this term is used to describe young tree seedlings that will form the next forest after harvesting or fire. The word 'regeneration' is also used in a more general sense to describe how a species renews itself from seed production to dispersal, germination, and establishment as a seedling.

remote

Distant, separated, widely spaced.

reniform

Kidney-shaped; a 2-dimensional shape, wider than long, with a broad rounded apex and 2 rounded basal lobes. See Figure 6.

repand

Leaf margins with very shallow indentations, cut less than 1/16 the distance to the midrib. See Figure 9.

resinous

Referring to the presence of resin, often fragrant and sticky; e.g., the resinous buds of balsam poplar (Populus balsamifera).

resupinate

Describes flowers in which the ovary or pedicel is twisted 180°, so that the lip of the flower is situated at the bottom; most orchid flowers are resupinate.

reticulate

Describes the prominent venation pattern on the lower leaf surface of some species; e.g.: netvein willow (Salix reticulata) and autumn willow (Salix serissima).

reticulate venation

See 'net venation'.

retrorse

Bent backwards; e.g., the retrorse barbs of some bedstraw (Galium) leaves.

retuse

A rounded apex with a shallow depression at the apex, not exceeding 1/16 of the distance to the centre of the leaf blade. See Figure 7.

revolute

Leaf margins that are rolled inward on the lower surface of the leaf; e.g., the leaves of Labrador tea (Rhododendron groenlandicum) have revolute margins. See Figure 9.

rhipidium

See 'scorpioid cyme'.

rhizomatous

Spreading by rhizomes.

rhizome

An underground stem, often long-creeping.

rhombic

A 3-dimensional diamond-shaped structure, with straight sides that taper to the base and apex; the widest measurement is at the middle.

rhomboidal

A 2-dimensional diamond shape, with straight sides of about equal length that taper to the base and apex; the widest axis is near the middle. Alternately called 'rhombic' in some sources, but this term is more appropriately applied to 3-dimensionals shapes. See Figure 6.

rhytidome

The outer bark of a tree, consisting of alternating layers of cork (periderm) separated by non-function secondary phloem cells.

rosette

A group of basal leaves arranged in a circular pattern around the base of a stem.

rostellum

A small beak-like structure found on the column of some orchid flowers, which separates the anther from the stigmatic surface of the column. The rostellum is formed by the middle lobe of the stigma in these orchid species.

rotate

An open corolla type, with a short tube and spreading lobes; petals are fused only at the base.

rounded apex

A curved apex (or base) with margins that form a smooth arc at the tip (or bottom) of the leaf. See Figures 7, 8.

rufous

Reddish-brown in colour.

rugose

With a wrinkled or rough texture, produced by the presence of numerous small impressed veins.

runcinate

An oblong to oblanceolate shape with irregular lacerate margins; e.g. the runcinate leaves of dandelion (Taraxacum officinale). See Figure 6.

saccate

Sac-shaped, as in the lip of some orchids; e.g., pink ladyslipper (Cypripedium acaule) flowers have a saccate lip.

sagittate

Arrow-shaped; a 2-dimensional shape with a pointed apex and two triangular basal lobes pointed downward. See Figure 6.

sagittate base

A leaf base with two triangular basal lobes that point downward. See Figure 8.

salverform

A type of corolla with a slender tube that abruptly flares outward into a flat or nearly flat circular short limb, oriented perpendicular to the tube; e.g., the salverform corollas of forget-me-not (Myosotis) or phlox (Phlox) flowers.

samara

A dry, indehiscent, 1-seeded, winged achene; e.g., the fruit of maple (Acer), ash (Fraxinus), or birch (Betula) are all samaras.

scabrous

Rough-textured; referring to a leaf surface with short stiff appressed hairs oriented towards the apex of the leaf; e.g., leaves of roundleaf dogwood (Cornus rugosa) have a scabrous upper surface. Leaf margins may also be scabrous, with short stiff recurved bristles or barbs, as in the finely barbed margins of bedstraw (Galium) leaves.

scale

A small thin highly modified bract.

scape

The leafless flowering stalk of a stemless plant.

scapose

A stemless forb, lacking above-ground stems; leaves and stems are all basal and develop from an underground stem (rhizome).

scatter-hoarding

The creation of small hoards of nuts or seeds by small seed-eating mammals (e.g., squirrels), or corvid birds (e.g., jays). This behaviour plays an important role in the dispersal of larger seeds and nuts, since many of the seeds remain uneaten by spring and are then able to germinate if stored in conditions suitable for germination.

schizocarp

A dry dehiscent fruit, typical of the Carrot Family (Apiaceae); derived from an inferior ovary with 2 carpels. At maturity, the schizocarp separates into 2 segments (mericarps); e.g., the fruits of cow parsnip (Heracleum maximum) are schizocarps.

scorpioid cyme

A determinate inflorescence (monochasial cyme), in which new flowers develop on alternating sides of each successive pedicel, producing a somewhat zig-zag flowering axis. There are two types of scorpioid cymes: a cincinnus is a scorpioid cyme in which each successive flower has a shorter pedicel, which produces a coiled apex; e.g., forget-me-nots (Myosotis) have their flowers arranged in a scorpioid cyme coiled at the apex. A rhipidium is a scorpioid cyme in which each successive flower has pedicels of about the same length, produce in elongate inflorescence with a zig-zig arrangement of pedicels, e.g., the inflorescence of bittersweet nightshade (Solanum dulcamara) is a rhipidium. See Figure 16.

scurfy

Covered with small scales and slightly rough to the touch, a texture similar to that of worn-out sandpaper; e.g., the scurfy buds of northern wild raisin (Viburnum cassinoides).

secondary veins

Smaller veins (strands of vascular tissue) branching off from the midrib of a leaf. See Figure 1.

section (§)

A taxonomic subdivision between the rank of Genus and Species; &00A7; is the symbol used to represent Section.

secund

A flower arrangement in which all of the flowers are situated on, or directed to, one side of the rachis; e.g., the secund flowers of one-sided wintergreen (Orthilia secunda).

seed

A mature ovule.

semi-serotinous cones

Gymnosperm cones that release their seed gradually over many years, except following fire, in which case, most of the seed crop is released from the cones after exposure to fire.

senescent

Describes stems or other organs that are aging or dying.

sepal

The outer sterile whorl of a flower, usually green in colour. Sepals cover a developing flower in bud. See Figure 11.

septa

A wall or partition that separates the carpels in a compound ovary (plural: septae).

septate

Divided internally by septa or partitions, e.g., the septate leaves of some Juncus species.

septate-nodulose

Describes Carex leaves that have prominent cross-partitions between veins.

septicidal capsule

A type of capsule that dehisces through the partitions (septae) between locules, keeping each locule intact.

septum

A translucent partition that separates the 2 carpels of a silique or silicle, the types of fruits characteristic of plants in the Mustard Family (Brassicaceae).

sericeous

A type of pubescence, bearing long silky hairs.

serotinous

In cones: Fire-adapted gymnosperm cones that release their seeds only after exposure to fire or extreme heat, rather than at maturity or soon after. Flowering time: Late flowering; with flowers that bloom after the leaves emerge. See also 'coetaneous' and 'precocious'.

serrate

Saw-like; toothed leaf margins with pointed teeth directed forward, towards the apex of the leaf. See Figure 9.

serrulate

Finely serrate; toothed leaf margins with very small pointed teeth directed forward, towards the apex of the leaf. See Figure 11.

sessile

Attached directly to the stem; sessile leaves lack petioles. See Figure 5.

setiform

Bristle-like structures.

setose

A type of pubescence; bearing stiff hairs or bristles.

shade-intolerant

Describes tree species that require full sunlight in order to germinate and grow; shade-intolerant tree species cannot compete with shade-tolerant species within a forest stand, and usually occur on land disturbed by fire, erosion, or harvesting activities; e.g., black spruce (Picea mariana) seedlings are shade intolerant.

shade-tolerant

Describes tree species that are able to germinate and grow in shaded conditions, such as within a forest stand; e.g., balsam fir (Abies balsamea) seedlings are shade-tolerant.

shallow-rooted

"Describes trees with lateral roots confined to the top 30-60 cm of soil, usually growing in the duff layer; trees of shallow-rooted species are more susceptible to windthrow than deep-rooted species.

sheath

Re: grasses: The tubular portion of a grass leaf, which surrounds the culm. Re: horsetails: A short, tubular sleeve at each node, formed by the fusion of the narrow leaves.

sheathing

Describes sessile leaves with the lower portion of the leaf wrapped in a tubular manner around the stem. Most grasses have sheathing leaves. See Figure 5.

shrub

A woody plant with several main stems; shrubs range in size from a few centimeters (dwarf shrubs) to several metres in height.

sigmoid

S-shaped, e.g., the sigmoid style of some wintergreen (Pyrola) species.

signal

A lighter area near the base of petaloid sepals in Iris flowers; in purple flowers, the signal is white, yellow towards the base, and strongly lined with dark purple veins; in yellow flowers, the signal is a deeper yellow, faintly lined with maroon veins.

silicle

A short silique, often flat, and usually broader than long, with the partition (septum) between the 2 carpels oriented perpendicular to the fruit wall; e.g., the fruits of shepherd's purse (Capsella) and peppergrass (Lepidium) fruits. See also 'silique'.

silique

A dry, dehiscent fruit, derived from 2 or more carpels that dehisce along 2 sutures, with the carpel walls (valves) separated by a translucent septum, which is rimmed by a placental replum. The carpel walls are dehiscent, leaving only the persistent septum and replum after seeds are shed; siliques are typically more than 3 times as long as broad and the septum is oriented parallel to the fruit wall; e.g., the fruits of mustard (Brassica) and rockcress (Arabis). Siliques are characteristic of the Brassicaceae. See also 'silicle'.

simple cyme

A determinate inflorescence in which the first flower to open is at the apex (centre) of the inflorescence, with new flowers developing laterally on either side of the first flower. See Figure 16.

simple fruit

A fruit formed from a single flower with 1 pistil; e.g., grape and tomato fruits.

simple leaf

A leaf with a single undivided blade. See Figure 1, 3.

sinuate

Describes a leaf margin with alternating short rounded lobes and shallow indentations with rounded sinuses, giving the margin a wavy appearance, but within the same plane as the leaf blade (adj.: sinuous). Compare to 'undulate'. See Figure 9.

snowbeds

Depressions in alpine areas where snow accumulates and lingers into summer; a number of alpine species are associated with late-melting snowbeds, also known as zabois.

solitary flower

A single flower borne on a peduncle.

sonication

Also known as buzz pollination; a type of pollination by larger bees (e.g., bumblebees) in which pollen grains, released inside an anther, are vibrated until the pollen is shaken out of the anther opening; e.g., blueberry (Vaccinium) flowers require sonication. Note that honeybees cannot sonicate, so cannot effectively pollinate blueberry flowers.

sorus

A cluster of sporangia on fern fronds (plural: sori).

spadix

An indeterminate spike-like inflorescence, usually elongate or ovoid, in which several flowers are situated on, or their ovaries embedded in, a fleshy axis. A spathe if usually subtended by a petaloid spathe; e.g., wild calla (Calla palustris) inflorescences have a spathe and spadix.

spathe

A modified leaf, often petaloid, that subtends or surrounds an inflorescence; e.g., the white spathe in wild calla (Calla palustris) plants subtends a spadix of small flowers. See also 'spadix'.

spatulate

Spoon-shaped in outline; a 2-dimensional shape, oblanceolate with a rounded apex, but tapering abruptly to the base. See Figure 6.

specialist pollination

A type of pollination, found in plant species that have highly modified stamens or pistils, requiring a select group of pollinators to effectively pollinate a given species or type of flower. Blueberry (Vaccinium) flowers have a specialized pollination mechanism, called sonication or buzz pollination, that requires large bees to vibrate (or sonicate) the stamens until pollen grains are released from the anthers.

spicate racemes

A raceme in which the pedicels are very short and may not be visible without close examination, causing the inflorescence to look more like a spike than a raceme.

spike

An unbranched, elongate inflorescence with sessile flowers attached directly to the axis of the inflorescence. See Figure 15.

spikelet

The primary inflorescence of grasses and sedges. In grasses, spikelets are usually composed of 3 stamens and/or a single pistil subtended by two small bracts, the palea (situated closest to the sexual organs) and the lemma (situated outside the palea). In sedges, spikelets are usually composed of a single bract (staminate or pistillate scale) subtending a male flower (with 3 stamens), a female flower (with 1 pistil), or a bisexual flower (with 3 stamens and 1 pistil). Spikelets may be further organized into secondary inflorescences, such as spikes, corymbs, racemes, or panicles, etc.

spine

A slender, sharply pointed structure derived from a modified leaf, stipule, or other leaf part. See also: thorns.

spinulose

Bearing teeth that end in small spine-like tips.

sporangia

An asexual reproductive structure in which spores are produced.

sporangiophore

In horsetails (Equisetum), the sterile peltate structure of a strobilus to which sporangia are attached; each peltate sporangiophore has a central stalk that expands to a broader hexagonal apex; 6 sporangia are attached to the lower surface of each sporangiophore, around the stalk.

sporophore

The fertile portion or branch of fronds belonging to species in the Ophioglossaceae; e.g., (Botrychium).

sporophyll

A microphyll or scale that bears or subtends a sporangium.

spur

In flowers, a modified petal or portion of a corolla that forms a hollow rounded, oblong, or tubular projection at the base; nectar is usually produced at the base of a spur, making it available only to long-tongued pollinators; violets (Viola) and some orchids have a spurred lower petal.

stamen

The male reproductive organ of a flower; stamens are composed of an anther supported by a filament. See Figure 11.

staminate flowers

Flowers that contain only male reproductive organs.

staminate scales

Small modified bracts that subtend male flowers in Carex spikes.

staminate spikes

Spikes composed of all male (staminate) flowers.

staminode

A sterile stamen or stamen-like structure found in some flowers, often serving as an attractant to pollinators; e.g., the staminodia of grass-of-Parnassus (Parnassia). In ladyslipper orchids (Cypripedium), the central anther is modified into a large shield-shaped staminode.

stellate

Star-shaped, as in the branched hairs on the leaves of some draba (Draba) species.

stellate-pubescent

A type of pubescence, bearing branched, star-shaped hairs.

stem

The main axis of a vascular plant, from which leaves and flowers are produced.

stigma

The pollen receptive portion of a pistil. See Figure 11.

stipe

The stalk of a fern frond, corresponding to the petiole of a leaf.

stipitate

Stalked, referring the base of a perigynium or achene.

stipitate-glandular

Bearing stalked glands, situated at the tip of stiff hairs.

stipular scars

Scars on a twig that indicate where stipules were previously attached; most stipule scars are small to minute and occur in pairs on opposite sides of a leaf scar.

stipular spine

A slender, sharply pointed spine developed at the nodes from a modified stipule, usually occurring in pairs; e.g., the stipular spines of smooth gooseberry (Ribes hirtellum).

stipulate leaf

A leaf that bear stipules.

stipules

A pair of small, leaf-like structures located at the base of a petiole. Not all leaves have stipules, but when present, they are often helpful in identification. See Figure 3.

stolon

A slender above-ground stem that creeps along the ground and roots at the apex to produce new plants; also called a 'runner'.

stone

The pit of a drupe, formed by the hard, inner layer (endocarp) of the fruit, which surrounds the seed. The fruit of cherries and peaches are also called stone fruit due to their hard pits.

stramineus

Straw-coloured, light yellowish-brown.

strigose

A type of pubescence; bearing straight stiff hairs, appressed to the surface.

strobilus

The reproductive, spore-bearing structure in horsetails (Equisetum) and some lycophytes (plural: strobili).

stylar orifice

A circular opening in a hypanthial disk of a flower, through which the styles emerge; e.g., the hypanthium of rose (Rosa) flowers has a stylar orifice.

style

The stalk between an ovary and a stigma. See Figure 11.

stylopodium

The enlarged base of the 2 styles in flowers of the Carrot Family (Apiaceae).

subassociation

Within the hierarchy of a vegetation classification, a subdivision of the association. Within the context of the Newfoundland vegetation classifications, subassociations usually reflect variations within an association due to soil moisture and nutrients. For example, in Newfoundland the Abietum Association is subdivided into the Abietum typicum on nutrient-poor well-drained sites, Abietum hylocomietosum on medium-nutrient moist sites; and Abietum rubetosum on nutrient-rich somewhat wet sites.

subcordate

Slightly cordate, with low or narrow rounded lobes at the leaf base.

submergent

Growing below the water surface; plant rooted in standing water (ponds, streams), with their leaves all retained below the surface of the water.

substrate

The substance, usually soil or bedrock, on or in which a plant grows or roots.

subtend

Situated below a structure.

subterranean

Growing below the ground.

subulate

Awl-shaped; linear, with parallel sides and tapering to a sharp point at the apex; e.g., needles of ground juniper (Juniperus communis). See Figure 6.

succession

The gradual change that occurs in vegetation of the earth's surface in which one population succeeds the other (Tansley 1920). Two types of vegetation succession are recognized: primary succession occurs on sites not previously vegetated, while secondary succession occurs after vegetated areas have been disturbed.

succulent

Fleshy or juicy, as in the fruit of raspberries or strawberries.

superior ovary

An ovary situated in a flower above the attachment of the stamens, petals, and sepals to the receptacle. See Figure 12.

sympodial rhizomes

Creeping rhizomes in which the terminal bud produces aerial leafy shoots or flowering culms, while lateral buds give rise to new rhizomes; this type of growth can produce broad patches or colonies of plants. Compare to 'monopodial rhizomes'.

syngenesious

Stamens that have fused (connate) anthers, but free filaments. In flowers of the Aster Family (Asteraceae), the syngenesious stamens form a ring around the pistil; pollen is shed to the inside of the ring and the expanding stigma pushed the pollen upward through the ring of anthers, where it is then available to pollinators.

synonym

A scientific name that is not the accepted name for a species, but refers to the same species by a different name. When the name of a plant is changed officially, for whatever reason, the previous name becomes a synonym of the newly designated name.

synonymous

(adj.) Describes different names that refer to the same species.

synsepal

In ladyslipper (Cypripedium) flowers, the fused lateral sepals that subtend the lip.

taproot

A large central root axis with smaller roots branching off from the taproot.

tawny

Tan, or light orangish-brown to yellowish-brown in colour.

tendril

A slender, coiled, vegetative structure designed to help stabilize or support a plant by coiling around a stationary structure; tendrils are usually situated at the apex of a leaf, in place of a terminal leaflet; e.g. the leaves of beach pea (Lathyrus japonicus) end in a tendril.

tepals

A collective term for perianth parts, when the sepals and petals are similar in colour and size. See Figure 11.

terete

Cylindrical and solid, circular in cross-section.

terminal bud

A bud located at the tip of a branch or twig; terminal buds are not subtended by leaf scars. See Figure 13.

ternately compound

A compound leaf with leaflets divided into three main sections.

terrestrial

Growing on the ground, above the surface of the soil.

tetradynamous

A stamen arrangement of 6 stamens, with 1 pair of short stamens and 2 pair of longer stamens; the characteristic arrangement of stamens in members of the Mustard Family (Brassicaceae).

thallus

A small plant body not differentiated into stems and leaves; e.g. duckweed (Lemna) plants.

thorn

A hard, sharply pointed, modified shoot or branch of a stem. Thorns contain vascular tissue but do not subtend buds, as they originated from a bud; however, buds may be present on thorns; e.g., hawthorn (Crataegus) thorns often bear small buds.

thyrse

A compound inflorescence with an indeterminate central axis and lateral branches that are determinate, usually dichasial cymes. See Figure 16.

tomentose

A type of pubescence; densely hairy with matted woolly hairs; e.g., the leaves of Labrador tea, (Rhododendron groenlandicum) are tomentose on the lower surface.

torus

The narrow conical receptacle of raspberry and blackberry (Rubus) flowers and fruit, with pistils attached along its length; separating easily from the fruit in raspberries, not separating in blackberries.

tree

A tall woody plant with a single main stem (trunk); trees can range in size from a few metres to several metres in height.

tricolored

Three-coloured.

trifoliate

A plant with only 3 leaves, e.g., nodding trillium (Trillium cernuum).

trifoliolate

A compound leaf with 3 leaflets; e.g., clover (Trifolium) leaves.

trigonous

Three-angled in cross-section; usually used to describe the shape of Carex achenes or stems.

tripinnate

A compound leaf or fern frond with the blade pinnately subdivided three times.

trophophore

The sterile photosynthetic portion of a fern frond in the Adder's Tongue Family (Ophioglossaceae); e.g., mature fronds of moonworts (Botrychium, Botrypus, and Sceptridium) all have a sterile trophophore and a fertile sporophore.

trullate

A 2-dimensional shape; resembling a trowel blade, i.e., similar to rhomboidal, but having 4 straight sides of unequal length, with the widest axis below the middle and a length to width ratio between 3:2 and 2:1. See Figure 6.

truncate apex

Straight or flat at the top; appearing cut off. See Figure 7.

truncate base

A broad straight leaf base. See Figure 8.

tryma

A type of accessory fruit, with an outer dehiscent layer, composed of involucral tissue fused to the outer fruit layers (exocarp and mesocarp), that surrounds a hard, bony inner layer (endocarp), containing the seed. The outer husk splits into 4 valves to reveal the hard nut-like endocarp; e.g., the fruit of shagbark hickory (Carya ovata).

tuber

An enlarged storage stem that develops from a rhizome; e.g., potatoes and yams are examples of tubers.

tuckamoor

The local common name for krummholz, in which the growing tips of conifer trees are pruned back (killed) by exposure to high winds, frost, and extreme cold, resulting in a dense crown of low branches; tuckamoor is most often found in coastal areas and where snow accumulates, such as in ravines and late melting snowbeds (zabois).

turbinate

A 3-dimensional shape; inversely conical, like an inverted cone.

turion

An overwintering vegetative bud, resistant to winter conditions and typically found in aquatic plants; e.g., in bladderworts (Utricularia), a globose or ovoid turion is produced by a proliferation of tiny leaves at the shoot apex.

tussock

A dense tuft-like growth form, typical of some sedges or grasses.

ultramafic

Rocks of volcanic origin (igneous rocks) that have a high magnesium, iron, and often nickel and chromium content, but a low silica and carbonate content, such as the serpentine (peridotite) rock of GMNP's Tablelands; also known as ultrabasic rocks.

umbel

A rounded or domed inflorescence in which the pedicels of each flower are attached to the main axis at the same point. Umbels may be determinate or indeterminate. See Figure 15.

umbellet

A simple umbel within a compound umbel, with each umbellet terminating a ray; the secondary (smaller) umbels of a compound umbel.

umbo

The tip of an apophysis (the exposed end of a cone scales) in pines, often ending in a hook or prickle.

umbraculate

Umbrella-shaped, as in the broad umbrella-shaped stigma that arches over the stamens and ovary in pitcher plant (Sarracenia purpurea) flower.

undulate

A leaf margin that appears wavy when viewed from the side; similar to the crests and troughs of waves, the undulations are above or below the plane of the leaf blade. Compare to 'sinuate'. See Figure 9.

unifacial

1-face (aka: monofacial), referring to flat or rounded leaves, usually vertically-oriented, and lacking distinct upper or lower surfaces; in flattened unifacial leaves, the edge of the leaf faces the stem; vascular tissue is arranged in bundles, with the phloem oriented closest to the surface of the leaf; e.g., leaves of rushes (Juncus spp.), or blueflag iris (Iris versicolor). See also 'bifacial'.

unisexual

Flowers that have only male or female sexual organs.

urceolate

An urn-shaped corolla; e.g., blueberry (Vaccinium) flowers have an urceolate corolla.

utricle

A small, dry, indehiscent, 1-seeded fruit with a thin bladdery or inflated perianth, typical of the Amaranth Family (Amaranthaceae).

vallecular canals

Hollow tubular channels in the cortex of horsetail stems, situated opposite the grooves (or valleys) between each ridge; vallecular canals are also called cortical canals. In cross-section, vallecular canals appear as a ring of empty circles closest to the outside of the stem.

valvate

Meeting at the edges, but not overlapping.

valvate scales

Bud scales that meet at the edges and do not overlap, e.g., the valvate bud scales of mountain maple (Acer spicatum) buds.

vascular bundles

Strands of vascular tissue (xylem and phloem) that transport food and water through a stem and leaf. After dehiscence, the number of vascular bundles in a petiole is visible on the leaf scar of a twig (see bundle trace scars).

vascular plants

Plants that have vascular tissue – thick-walled tissues that conduct food and water throughout the plant, and provide strength to stems. Vascular plants include flowering plants, conifers, and pteridophytes (ferns and related plants).

velutinous

A type of pubescence; bearing velvety hairs.

vernation

The arrangement of young emerging leaves, as in the circinate (coiled) vernation of fern fronds.

verrucose

A surface texture with numerous small bumps or warty protrusions; e.g., the warty of verrucose stems of lowbush blueberry (Vaccinium angustifolium).

verticillaster

A determinate inflorescence with whorls of dichasia arranged around each node of the flowering axis. The verticillaster is the type of inflorescence characteristic of the Mint Family (Lamiaceae).

villous

A type of pubescence; bearing long soft hairs.

viscidium

A sticky pad at the base of a pollinium that attaches the pollinium to a visiting insect, usually to its head or thorax, where it is in position to be transferred to the stigmatic region of the column of another orchid flower.

vittae

Resin ducts on the surface of each mericarp in the fruit (schizocarps) of the Carrot Family (Apiaceae).

viviparous

Describes a plant that, in place of some or all flowers, produces small plant-like structures (plantlets), capable of growing into new plants; a form of vegetative propagation; e.g., proliferous fescue (Festuca prolifera).

whorled

A leaf arrangement with three or more leaves attached at each node of the stem. See Figure 4.

windfirm

Describes trees that are usually deep-rooted and able to withstand high winds without uprooting or breaking.

windthrow

The uprooting or breaking of a tree trunk due to high wind.

wing

In papilionaceous flowers, the 2 lateral petals of the flower.

woody plants

Perennial plants with woody stems, including dwarf shrubs, tall shrubs, and trees.

woolly

A type of pubescence; covered with long matted hairs, similar in texture to sheep's wool.

xylem

The water-transporting system of cells in the vascular system of a plant; the wood in tree trunks and stems is composed of xylem cells.

zabois

Late-melting alpine snowbeds.

zonal vegetation

A climatic climax vegetation that has developed without significant human influence on habitats that are not subject to excessive moisture or drought. Within our region, this usually equates to a midslope position; e.g., in the Central Newfoundland Ecoregion, the zonal vegetation is the Abietum hylocomietosum Subassociation while the Western Ecoregion is defined by the Abietum dryopteretosum Subassociation.

zoochory

Dispersal of fruits or seeds by animals (adj.: zoochorous). There are two main types of zoochory: epizoochory and endozoochory, based respectively on whether the seed or fruit is dispersed on or inside the animal.

zygomorphic

A type of floral symmetry in which a single line drawn through the centre of a flower (usually vertical), will produce a mirror images on the left and right sides of the line. A line drawn on a different plane through the same flower will not produce identical images on either side of the line. Also called irregular symmetry.