Illustrated Flora of Prince Edward Island


See also Harris and Harris (1994).

Abaxial - the lower surface, or the surface away from the axis. Compare adaxial
Achene - a dry, indehiscent one-seeded fruit
Acroscopic - oriented towards the terminal end. Compare basiscopic
Actinomorphic - radially symmetrical
Acuminate - gradually tapering to a sharp point, the sides becoming concave. Comparer mucronate
Acute - tapering to a pointed apex, the sides remaining straight and forming an angle less than 90 degrees. Compare obtuse
Adaxial - the upper surface, or the surface closest to the axis. Compare abaxial
Alternate - arranged alternately, e.g. with a single leaf present per stem node. Compare opposite, whorled
Androgynous - having the male parts borne above or distal to the female parts. Compare gynecandrous
Annual - completing one's life cycle in a single growing season
Anther - the expanded, apical portion of the stamen that bears pollen
Anthesis - when a flower is fully expanded and functional, the flowering period
Anthocyanic - containing anthocyanis, with red to violet pigmentation
Antrorse - directed forward or apically. Compare retrorse
Apical - located at the apex or terminal end
Apiculate - having a short flexible point
Appressed - oriented close or pressed against another organ
Arcuate - curved, like a bow
Aril - a fleshy thickening of the seed coat, as in Canada Yew (Taxus canadensis)
Ascending - arched upwards
Astringent - producing a dry mouthfeel when eaten (e.g. with Prunus virginiana, Aronia spp.)
Attenuate - very gradually tapered to a slender apex or base
Auricle - a protruding lobe, usually small, at the attachment point of a leaf
Awn - a long, bristle-like appendage
Axil - the angle between two parts, e.g. the rachis and a panicle branch
Basal - positioned or arising from the base, as in leaves arranged at the base of a stem. Compare cauline
Barbellate - finely barbed
Basiscopic - oriented towards the base. Compare acroscopic
Berry - a fleshy fruit produced from a single ovary
Biennial - species that complete their life cycle in two years
Bifid - forked, split in two at the apex
Bilateral - arranged on two sides of an axis
Bipinnate - pinnate twice, with initial division pinnately divided once more
Bisexual (flowers) - having both male and female floral organs borne in a single flower
Bract - a reduced leaf at the base of a flower or inflorescence; in conifers, bracts arise from the axis of the seed cone
Bracteole - a smaller bract, often subtending larger bracts
Bractlet - a small bract
Caespitose - see cespitose
Callus - (grasses) the hardened base of a floret, where it attaches to the rachilla
Calyculate - see calyculus
Calyculus - a whorl of bracts below the calyx, or (Asteraceae) below the involucre
Calyx - the collective name for all sepals of a flower; the outer perianth whorl
Campanulate - bell-shaped
Capillary - slender, hair-like
Capitate - having a head-like tip
Capitulescence - a compound inflorescence consisting of capitula
Capitulum - an inflorescence consisting of a head of small closely packed florets (Asteraceae)
Capsule - a dry, dehiscent fruit with more than one carpel
Cartilaginous - hardened, tough
Carpel - a simple pistil, or one component of a compound pistil
Caruncle - a protuberance on the tip of a fruit, usually wart-like, sometimes elongate.
Caudex - a thickened, often woody, vertical or branched perennial stem; usually underground
Cauline - relating to the stem, as in leaves borne on the stem above the ground. Compare basal
Cespitose - tufted, several stems rising from a clump
Chaff - thin, dry scales or bracts
Chlorophyllous zone (Symphyotrichum) - a green-coloured area at the tips of phyllaries
Cilia - very small fine hairs, usually confined to the margins of an organ
Ciliate - covered in cilia
Clavate - club-shaped, gradually widening to a clubbed apex
Compound leaf - a leaf consisting of multiple leaflets
Conical - cone-shaped, tapering away from point of attachment
Connate - fused, as in the fusion of staminal filaments to form a tube
Cordate - heart-shaped, i.e., with a sinus at the base
Corm - fleshy, swollen stem base, usually underground
Corolla - the collective name for all petals of a flower; the inner perianth whorl
Corymb - a flat-topped inflorescence with branches arising at different points
Crenate - rounded teeth. Compare dentate, serrate
Culm - an aerial stem bearing the inflorescence, from the base of the plant to the inflorescence (usually grasses, sedges, rushes, many monocots)
Cuneate - tapering in a wedge-shape
Cuspidate - tipped with a hard, pointed tip
Cyme - an inflorescence in which all axes are terminated with a flower
Cypsela - an achene with a pappus attached (Asteraceae)
Deciduous - referring to an organ dehiscing and falling seasonally
Decumbent - growing horizontally along the ground and turning upward at the tips
Dehiscent - opening at maturity to release contents, as in fruit releasing seeds or anthers releasing pollen. Contrast indehiscent
Deltate, deltoid - shaped like an equilateral triangle
Dentate - toothed, the teeth pointing outward. Compare crenate, serrate
Denticulate - finely toothed
Dimorphic - with two forms
Dioecious - in which male and female reproductive structures are borne only on different individuals. Contrast monoecious
Disarticulation - the point of separation at maturity, e.g. (grasses) "disarticulation above the glumes" refers to a spikelet naturally falling off at maturity while the glumes persist
Disk flower - an actinomorphic flower in the capitulum (Asteraceae). Compare ray flower
Distal - toward the tip, or the end of an organ opposite its attachment point. Compare proximal
Dorsal - on the surface facing away from the axis
Drupe - a fleshy, indehiscent fruit with a stony inner layer enclosing usually a single seed, as in Cherries (Prunus)
Eciliate - without cilia
Elliptical - with the shape of an ellipse or narrow oval; broadest at the middle and narrower at the two equal ends
Endocarp - innermost layer of fruit, directly surrounding the seed
Entire - smooth, not toothed, lobed or incised
Epicalyx - an involucre resembling an outer calyx
Equitant - overlapping or straddling in two ranks, as in the leaves of Iris
Erose - having the margin irregularly frayed or incised
Exserted - protruding, e.g. stigma exserted from the perigynia
Fascicle - a cluster, as in a tuft of leaves arising from a single node
Filament - a thread-like structure, usually referring to the stalk of the stamen, supporting the anther
Fimbriate - fringed, usually with hairs
Flexuous - zig-zagging, or flexible
Floret - a small flower, often used for individual flowers in Poaceae and Asteraceae
Floricane - second year stems bearing flowers (Rubus). Compare Primocane
Foliaceous - leaf-like
Follicle - a dry fruit formed from a single carpel, splitting along a suture
Fringed - with hairs, bristles, or thin projections along the margins
Frond - the leaf of a fern or palm
Gemma - readily-detaching vegetative propagules, consisting of a ring of six leaves arranged in a cup-like shape, as in the Firmosses (Huperzia).
Geniculate - bent at a sharp angle
Glabrate - nearly glabrous
Glabrous - hairless
Glaucous - with a white or bluish waxy coating
Glume - paired bracts subtending the spikelet of a grass
Gynecandrous - having the female parts borne above or distal to the male parts. Compare Androgynous
Halophytic - tolerant of salt-influenced habitats
Head - a dense cluster of sessile to subsessile flowers
Hemipollinarium - half of a pollinarium
Herbaceous - like a herb, i.e., not woody or evergreen
Hirsute - with coarse, stiff, straight hairs
Hyaline - thin, membranous, transparent or translucent
Hypanthia - (Rosaceae) a tube or cup-like structure in a flower from which many floral whorls originate (usually the sepals petals and stamens)
Incised - cut deeply
Indehiscent - a type of fruit, not opening at maturity along defined lines or pores. Compare dehiscent
Imbricate - overlapping in rows
Indurate - hardened
Indusium - in ferns, an epidermal growth from the frond covering the sorus
Inferior - attached beneath, e.g. an ovary attached beneath the receptacle, as in Blueberries (Vaccinium). Compare superior
Inflorescence - the flowering portion of a plant; the arrangement of the flowers on the flowering axis
Internode - portion of a stem between two nodes
Involucre - a group of bracts surrounding the inflorescence
Involute - rolled inward, with the margins rolling towards the adaxial surface. Compare revolute
Involucral - pertaining to the involucre
Labellum - the highly-modified lip petal in orchid flowers
Lacerate - cut irregularly, as if torn
Lanceolate - lance-shaped, much longer than wide, the widest point below the middle
Lateral - borne on or at the side
Leaflet - the ultimate segments of a compound leaf
Lemma - the lower of two bracts subtending the flower of a grass
Lenticlular - lens-shaped
Ligule (grasses) - a small membranous or hairy appendage at the junction of a leaf sheath and blade
Linear - resembling a line; long and narrow with relatively parallel sides
Lobe - a division or segment or an organ such as a leaf
Locule - a cavity e.g. in an ovary containing seeds
Lustrous - shiny -
Midvein - the central vein, usually of a leaf
Monoecious - having male and female reproductive structures produced on the same individual, either in bisexual flowers or with unisexual flowers of both sexes present in an inflorescence. Compare dioecious
Monomorphic - with one form
Mucronate - tipped with an abrupt, short, sharp point. Compare acuminate
Myco-heterotrophic - deriving energy from fungal associations, usually mycorrhizae, rather than photosynthesis
Node - part of the stem where leaves or branches originate
Nodulose - small knob-like outgrowth on the surface of an organ
Oblanceolate - inversely lanceolate, the base narrower than the apex
Oblong - two to four times longer than broad, with nearly parallel sides
Obtuse - tapering or rounding to apex, with the sides forming and angle greater than 90 degrees. Compare acute
Opposite - arranged oppositely, e.g. with two leaves arising per node
Orbicular - roughly circular in outline
Ovary - the expanded basal part of the pistil containing the ovules
Ovate - egg-shaped in outline, broadest below the middle
Ovoid - egg-shaped (applied to three-dimensional features)
Ovule - an immature seed
Palea - the upper of two bracts subtending a grass flower
Palmate - radiating from a central point
Panicle - a branched racemose inflorescence. Compare raceme
Papilla - a small protuberance on the surface of an organ, extended from one epidermal cell
Papillose - covered in papillae
Pappus - the modified calyx in Asteraceae, attached on the top of the inferior ovary; may be a series of bristles, scale-like, or awns
Pectinate - having closely parallel, slender, toothlike projections like a comb
Pedicel - the stalk of a single flower, or a grass spikelet. Compare peduncle
Peduncle - the stalk of an inflorescence (more than one flower). Compare pedicel
Pedunculate - having a peduncle
Peltate - shield-shaped, the attachment point on the lower surface rather than an edge
Perennial - species whose life span extend over several years
Perianth - the calyx and corolla of a flower
Perigynia - a sac formed by modified bracts, surrounding and enclosing the fruit in Carex.
Petal - an individual segment or member of the corolla, usually coloured or white
Petiole - the stalk of a leaf
Petiolule - the stalk of a leaflet (in a compound leaf)
Phyllary - an involucral bract (Asteraceae)
Pilose - pubescent with long, soft, thin hairs
Pinna - the first division of a pinnate fern frond
Pinnate - as in a compound leaf or fern frond, fully divided into leaflets or pinnae along opposite sides of an elongate axis
Pinnatifid - as in a fern frond, pinnately cleft but not completely divided to the midrib or rachis
Pinnule - the pinnate division of a pinna in a bipinnately compound leaf or frond
Pistil - the female component of a flower, usually consisting of an ovary, style and stigma
Plane - flat, often in relation to another organ
Plano-convex - two-angled, with one side flat and one side convex
Pollinarium - in Orchids, the pollen-bearing structure that attaches to pollinators
Pome - a fruit developed mostly from the hypanthium (as in Malus)
Prickle - a hard pointed outgrowth from the surface of a plant, extensions of the cortex and epidermis. Compare thorn and spine
Primocane - vegetative first year stems (Rubus)
Procumbent - lying flat on the ground, not setting any roots
Prostrate - lying flat on the ground, often rooting at nodes
Proximal - toward the base or the attached end of an organ. Compare distal
Pruinose - covered in waxy bloom
Puberulent - covered with short, fine hairs
Pubescent - hairy
Pyrene - the stone within a drupe, consisting of a seed surrounded by a hard endocarp
Rachilla - the axis of a spikelet, bearing florets
Rachis - the midrib of a fern frond or axis of an inflorescence
Raceme - an unbranched, elongate inflorescence with pedicelled flowers. Compare spike, panicle
Radial - with structures radiating from a central point, as spokes on a wheel
Ray flower - strap-shaped and typically sterile florets that form the ray. Compare disk flower
Receptacle - the part of the pedicel where all floral parts are attached
Reduced - (relative) of smaller size
Reflexed - bent sharply downward
Remote - distant, e.g. spikes in an inflorescence distant from one another
Reniform - kidney-shaped
Resinous - viscid, having resin
Resupinate - upside-down, due to twisting of the pedicel, as in the flowers of most of our Orchids
Reticulation - forming a network, such as veins joining each other in multiple places
Retrorse - directed backward or basally. Compare antrorse
Revolute - rolled under, e.g. with leaf margins rolled toward the abaxial surface. Compare involute
Rhizome - a horizontal, underground stem
Rhombic - shaped like a rhombus
Rosette - appearing whorled due to very short internodes, usually referring to a basal cluster of leaves
Rugose - wrinkled or crumpled surface
Sagittate - shaped like an arrowhead (as in e.g., Sagittaria latifolia)
Scabrous - rough to the touch, with short hard hairs or protrusions
Scape - a leafless peduncle arising from ground-level, usually from a basal rosette
Scapose - having flowers borne on a scape
Scarious - dry and membranous
Secund - arranged on one side only (or appearing so)
Sepal - a segment of the calyx
Septate - having evident partitions
Serrate - with saw-like teeth, pointed and facing toward the apex. Compare dentate, crenate
Serrulate - finely serrate
Sessile - directly attached, not borne on a stalk
Setaceous - covered in setae
Seta - bristles or stiff hairs
Setose - see setaceous
Sheath - the portion of an organ which surrounds, at least partly, another organ, e.g. in grasses, where the bases of leaves form a sheath around the stem
Sheathing - forming a sheath
Simple leaf - undivided. Compare with compound leaf
Sinus - the depression or recess between two lobes or teeth
Sorus - a cluster of sporangia on the surface of a fern frond, usually covered by an indusium
Spadix - a spicate inflorescence with small flowers crowded on a thickened axis, as in Jack-in-the-pulpit (Arisaema triphyllum)
Spathe - a large bract subtending and often enclosing an inflorescence
Spatulate - spatula-shaped, broadest near the apex, gradually tapering to the base
Spike - an unbranched inflorescence with sessile (or subsessile) flowers. Compare raceme
Spikelet - part of a spike inflorescence, as in grasses and sedges and other monocots
Spine - a hard pointed outgrowth, highly modified leaves. Compare thorns and prickles
Sporangium - the spore-bearing case in ferns. Usually numerous and arranged in sori
Sporophore - the spore-bearing portion of a frond, as in Ophioglossaceae
Spreading - extending horizontally
Spur - a hollow, elongated, sac-like appendage of the calyx or corolla, as in Platanthera
Stamen - the male component of a flower, consisting of a filament and anther
Stellate - star-shaped
Stigma - the part of the pistil which is receptive to pollen
Stipe - a small stalk
Stipitate - having a stipe
Stipule - leaf-like appendages sometimes found at leaf-bearing nodes
Stolon - a prostrate or trailing stem, aboveground
Stomate (pl. stomata) - a pore or aperture surrounded by two guard cells, which allows gas exchange
Stramineous - straw-coloured
Striations - parallel longitudinal lines
Strobilus - a cone or an inflorescence resembling a cone, as in the Clubmosses (Lycopodiaceae)
Style - the usually narrowed stalk-like portion of the pistil connecting the stigma to the ovary
Subulate - awl-shaped
Superior - attached above, e.g. an ovary attached above the receptacle. Compare inferior
Tepal - a perianth whorl that cannot be defined as either a sepal or petal
Terete - round in cross-section
Terminal - at the tip or apex
Ternate - divided in threes, as in Bracken Fern (Pteridium aquilinum)
Thorn - a hard pointed outgrowth, modified branches or stems. Compare spines and prickles
Thyrse - a wand-shaped inflorescence in which the main axis grows indeterminately, and the branches have determinate growth
Tomentum - dense, short mat of hairs
Trifoliate - a compound of leaf of three leaflets (e.g. Trifolium)
Tripinnate - pinnately compound three times
Triseriate - in three series
Trophophore - the sterile, photosynthesizing portion of a frond, as in Ophioglossaceae
Truncate - with an abrupt, squared end
Tubercle - a small wart-like outgrowth
Umbel - a flat-topped or convex inflorescence with pedicels mostly arising from a common point, like an umbrella
Unisexual - bearing only male or female reproductive organs
Viscid - sticky or gummy
Villous - covered in long, curly, shaggy hairs
Whorled - arranged in whorls, e.g. with three or more leaves arising from a node
Zygomorphic - bilaterally symmetrical