Glossary
Page Last Updated: February 19 2012
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Phyllaries - bracts at the base of a composite (Aster family) flower head - also known as involucral
bracts - the picture at right shows phyllaries of Tall Beggar-ticks - the picture at far right shows the
phyllaries of Knapweed
bracts - the picture at right shows phyllaries of Tall Beggar-ticks - the picture at far right shows the
phyllaries of Knapweed
Cultivar - a 'cultivated variety" of a plant species that has been bred for desirable characteristics
such as flower colour or shape, crop yield or resistance to disease - genetically, a cultivar is not
sufficiently different from its host to be defined as a new species - the picture at right shows the
'Crimson King' cultivar of the Norway Maple tree
such as flower colour or shape, crop yield or resistance to disease - genetically, a cultivar is not
sufficiently different from its host to be defined as a new species - the picture at right shows the
'Crimson King' cultivar of the Norway Maple tree
Ootheca - an egg mass with a protective outer covering - produced by certain insects (notably
mantids and cockroaches) and mollusks - usually contains many eggs - the picture at right shows
the ootheca of a Praying Mantis
mantids and cockroaches) and mollusks - usually contains many eggs - the picture at right shows
the ootheca of a Praying Mantis
Pistil - the female part of a flower consists of the ovary (will become the fruit) and the stalk-like style
which supports the pollen receiving stigma - Stamen - the male part of a flower consists of the
stalk-like filament which supports the pollen producing anther - the number, appearance and
arrangement of pistils and stamens varies - some flowers have only a pistil (carpellate or
pistillate) or only a stamen (staminate) - the picture at right shows the reproductive structure of
Enchanter's Nightshade - the picture at far right shows the anthers and stigmas of Chicory
which supports the pollen receiving stigma - Stamen - the male part of a flower consists of the
stalk-like filament which supports the pollen producing anther - the number, appearance and
arrangement of pistils and stamens varies - some flowers have only a pistil (carpellate or
pistillate) or only a stamen (staminate) - the picture at right shows the reproductive structure of
Enchanter's Nightshade - the picture at far right shows the anthers and stigmas of Chicory
Autoecious - Rust fungus that can complete its life cycle on one host species - Heteroecious -
Rust fungus that requires two unrelated host species to complete its life cycle - there may be many
different potential hosts for a given species of Rust fungus - the picture at right shows the
Heteroecious Crown Oat Rust (hosts are Grass (barley, rye) and Buckthorn families) on its
alternate host European Buckthorn
Rust fungus that requires two unrelated host species to complete its life cycle - there may be many
different potential hosts for a given species of Rust fungus - the picture at right shows the
Heteroecious Crown Oat Rust (hosts are Grass (barley, rye) and Buckthorn families) on its
alternate host European Buckthorn
Monoecious - a plant that has male and female flowers (sometimes simultaneously, sometimes
at different times) - Dioecious - a plant that has only male (androecious - pollen / microspore
producers) or female (gynoecious - seed / megaspore producers) flowers - a hermaphrodite plant
(the majority of plants) has a flower with both male and female reproductive parts - the picture at
right shows the male and female flowers of Pennsylvania Sedge (monoecious) - the picture at
middle right shows the male and female flowers (on separate plants) of White Campion
(dioecious) - the picture at far right shows Trout Lily (hermaphrodite)
at different times) - Dioecious - a plant that has only male (androecious - pollen / microspore
producers) or female (gynoecious - seed / megaspore producers) flowers - a hermaphrodite plant
(the majority of plants) has a flower with both male and female reproductive parts - the picture at
right shows the male and female flowers of Pennsylvania Sedge (monoecious) - the picture at
middle right shows the male and female flowers (on separate plants) of White Campion
(dioecious) - the picture at far right shows Trout Lily (hermaphrodite)
Achene - one-seeded fruit in plants of the Aster (Composite) family (and others) that is often
accompanied by a pappus - Pappus - modified calyx in plants of the Aster (Composite) family that
is composed of bristles, hairs, teeth or scales that aid in seed dispersal - the picture at right
shows the achene and pappus of White Snakeroot (seed dispersed by wind) - the picture at far
right shows the achene and pappus of Tall Beggar-ticks (seed dispersed by attaching to
mammals or birds via two barbed teeth known as awns)
accompanied by a pappus - Pappus - modified calyx in plants of the Aster (Composite) family that
is composed of bristles, hairs, teeth or scales that aid in seed dispersal - the picture at right
shows the achene and pappus of White Snakeroot (seed dispersed by wind) - the picture at far
right shows the achene and pappus of Tall Beggar-ticks (seed dispersed by attaching to
mammals or birds via two barbed teeth known as awns)
Calyx - the outer segment of a flower that encloses a flower bud - the individual parts of the calyx
are petal-like structures called sepals - sepals are often green but when they are similar to (and
the same colour as) the petals they are referred to as tepals - the picture at right shows the calyx of
Hedge Bindweed - the picture at middle right shows the bladder-like calyx of Bladder Campion -
the picture at far right shows the sepals of Thyme-leaved Sandwort
are petal-like structures called sepals - sepals are often green but when they are similar to (and
the same colour as) the petals they are referred to as tepals - the picture at right shows the calyx of
Hedge Bindweed - the picture at middle right shows the bladder-like calyx of Bladder Campion -
the picture at far right shows the sepals of Thyme-leaved Sandwort
Pappus - see achene
Heteroecious - see autoecious
Sepal - see calyx
Tepal - see calyx
Dioecious - see monoecious
Androecious - see monoecious
Gynoecious - see monoecious
Ovary - see pistil
Stamen, Staminate - see pistil
Anther - see pistil
Filament - see pistil
Carpellate - see pistil
Spadix - a dense spike of small flowers on a fleshy stalk that is associated with (and sometimes
enclosed by) a spathe - the fruiting spadix is a dense cluster of berries - Spathe - a large bract -
characteristic of the Arum family - the picture at right shows the spadix and spathe of
Jack-in-the-Pulpit ("Jack" is the spadix, "Pulpit" is the spathe) - the picture at far right shows the
fruiting spadix of Jack-in-the-Pulpit
enclosed by) a spathe - the fruiting spadix is a dense cluster of berries - Spathe - a large bract -
characteristic of the Arum family - the picture at right shows the spadix and spathe of
Jack-in-the-Pulpit ("Jack" is the spadix, "Pulpit" is the spathe) - the picture at far right shows the
fruiting spadix of Jack-in-the-Pulpit
Awn - see achene
Composite - the Composite family (also known as Aster, Daisy or Sunflower family) is one of the
largest families of flowering plants - the flower head is not a single flower but a composite of many
disk and / or ray flowers (called florets or floscules) - the picture at top right shows Chicory which
only has ray florets - the picture at top far right shows White Snakeroot which only has disk florets -
the picture at bottom right shows Black-eyed Susan which has ray and disk florets - the picutre at
bottom far right shows a ray floret of Chicory containing both male and female parts - the ovary will
become an achene - 5 fused anthers form a tube around the style from which the stigma protrudes
- corolla consists of 5 fused petals
largest families of flowering plants - the flower head is not a single flower but a composite of many
disk and / or ray flowers (called florets or floscules) - the picture at top right shows Chicory which
only has ray florets - the picture at top far right shows White Snakeroot which only has disk florets -
the picture at bottom right shows Black-eyed Susan which has ray and disk florets - the picutre at
bottom far right shows a ray floret of Chicory containing both male and female parts - the ovary will
become an achene - 5 fused anthers form a tube around the style from which the stigma protrudes
- corolla consists of 5 fused petals
Floret, Floscule - see composite
Corolla - collective term for all the petals of a flower - the corolla and calyx are together called the
perianth
perianth
Perianth - see corolla
Scutellum - In zoology, the shield-like plate or scale on an insect thorax - typically a small triangle
at the base of the wings pointing to the tip of the abdomen - In botany, the shield-like structure of a
grass seed - the picture at right shows the scutellum of a Transverse Hover Fly - the picture at far
right shows the large scutellum of a Green Stink Bug
at the base of the wings pointing to the tip of the abdomen - In botany, the shield-like structure of a
grass seed - the picture at right shows the scutellum of a Transverse Hover Fly - the picture at far
right shows the large scutellum of a Green Stink Bug
Thorax - the mid-section of an insect to which the head (first or anterior section), abdomen (third or
posterior section), legs and wings are attached - composed of three segments, the prothorax (T1),
mesothorax (T2) and metathorax (T3) - Abdomen - the posterior section of an insect consisting of a
number of segments (11 in most orders but reduced in others) and containing the digestive tract
and reproductive organs - the picture at right shows the head, thorax and abdomen (segments A1
to A10) of a White Tail dragonfly - the picture at far right shows the head, thorax (segments T1 to
T3) and abdomen (segments A1 to A10) of an Underwing Moth larva
posterior section), legs and wings are attached - composed of three segments, the prothorax (T1),
mesothorax (T2) and metathorax (T3) - Abdomen - the posterior section of an insect consisting of a
number of segments (11 in most orders but reduced in others) and containing the digestive tract
and reproductive organs - the picture at right shows the head, thorax and abdomen (segments A1
to A10) of a White Tail dragonfly - the picture at far right shows the head, thorax (segments T1 to
T3) and abdomen (segments A1 to A10) of an Underwing Moth larva
Hermaphrodite - see monoecious
Haltere - also halter - modified wings of some insects that act as a gyroscope and help in
maintaining stability and executing high speed maneuvers during flight - in flies, the hindwings
have evolved into halteres while in some other species, the forewings have evolved - the picture at
right shows the halteres of a Band-winged Crane Fly - the picture at far right shows the halteres of
a Tachinid fly
maintaining stability and executing high speed maneuvers during flight - in flies, the hindwings
have evolved into halteres while in some other species, the forewings have evolved - the picture at
right shows the halteres of a Band-winged Crane Fly - the picture at far right shows the halteres of
a Tachinid fly
Prothorax - the 1st or anterior (T1) of 3 segments in the thorax of an insect - bears the first pair of
legs - mesothorax - the 2nd (T2) of 3 segments in the thorax of an insect - bears the 2nd pair of
legs and the forewings (when present) - metathorax - the 3rd or posterior (T3) of 3 segments in the
thorax of an insect - bears the 3rd pair of legs and the hindwings (when present) - the picture at
right shows the forewings and hindwings of a Silvery Blue Butterfly
legs - mesothorax - the 2nd (T2) of 3 segments in the thorax of an insect - bears the 2nd pair of
legs and the forewings (when present) - metathorax - the 3rd or posterior (T3) of 3 segments in the
thorax of an insect - bears the 3rd pair of legs and the hindwings (when present) - the picture at
right shows the forewings and hindwings of a Silvery Blue Butterfly
Pronotum - one of the main sclerites (exoskeletal plates) in the prothorax of an insect forming the
upper (dorsal) surface - in beetles and treehoppers, the pronotum is greatly exaggerated, aiding in
identification - the picture at right shows the pronotum of a Locust Borer Beetle - the picture at far
right shows the pronotum of a Buffalo Treehopper
upper (dorsal) surface - in beetles and treehoppers, the pronotum is greatly exaggerated, aiding in
identification - the picture at right shows the pronotum of a Locust Borer Beetle - the picture at far
right shows the pronotum of a Buffalo Treehopper
Spiracle - respiratory pore, especially those located along the sides of insects - the spiracles of a
caterpillar (Butterflies and Moths) appear on the 1st thoracic segment (T1) and the 1st through 8th
abdominal segments (A1 to A8) - the coloured area circling some spiracles often aids in
identification - the picture at right shows the T1 spiracle of an Underwing Moth larva - the picture at
far right shows the A1 to A4 spiracles of a Pandorus Sphinx Moth larva
caterpillar (Butterflies and Moths) appear on the 1st thoracic segment (T1) and the 1st through 8th
abdominal segments (A1 to A8) - the coloured area circling some spiracles often aids in
identification - the picture at right shows the T1 spiracle of an Underwing Moth larva - the picture at
far right shows the A1 to A4 spiracles of a Pandorus Sphinx Moth larva
Stigma - in botany, see pistil - in zoology, a spiracle - also a coloured cell on the leading edge of
each wingtip in a dragonfly or damselfly (formally pterostigma) - nodus - the shallow notch at the
midpoint of the leading edge of each wing in a dragonfly or damselfly - origin of several veins that
add strength and flexibility to the wing - the picture at right shows the stigma and nodus of a
4-spotted Skimmer Dragonfly
each wingtip in a dragonfly or damselfly (formally pterostigma) - nodus - the shallow notch at the
midpoint of the leading edge of each wing in a dragonfly or damselfly - origin of several veins that
add strength and flexibility to the wing - the picture at right shows the stigma and nodus of a
4-spotted Skimmer Dragonfly
Style - see pistil
Nodus - see stigma
Median stripe (damselflies) - dark stripe that runs along the centre of the thorax, sometimes
bisected by the pale Middorsal stripe - Antehumeral stripe - pale stripe below the median stripe on
either side of the thorax - Humeral stripe - dark stripe below the antehumeral stripe on either side
of the thorax - additional stripes may be present below the humeral stripe - pattern on dragonflies
is more complex - Postocular spots - pale marks just below the eyes (not always present) - the
picture at right shows the median stripe and postocular spot of an Eastern Forktail Damselfly - the
picture at far right shows the stripes of a Slender Spriead-wing Damselfly
bisected by the pale Middorsal stripe - Antehumeral stripe - pale stripe below the median stripe on
either side of the thorax - Humeral stripe - dark stripe below the antehumeral stripe on either side
of the thorax - additional stripes may be present below the humeral stripe - pattern on dragonflies
is more complex - Postocular spots - pale marks just below the eyes (not always present) - the
picture at right shows the median stripe and postocular spot of an Eastern Forktail Damselfly - the
picture at far right shows the stripes of a Slender Spriead-wing Damselfly
Antehumeral stripe - see median stripe
Humeral stripe - see median stripe
Middorsal stripe - see median stripe
Postocular spot - see median stripe
Pterostigma - see stigma
Biennial - see annual
Perennial - see annual
Herbaceous plant - see annual
Woody plant - see annual
Umbel - see inflorescence
Capitulum - see inflorescence
Catkin - see inflorescence
Ament - see inflorescence
Corymb - see inflorescence
Cyme - see inflorescence
Head - see inflorescence
Panicle - see inflorescence
Raceme - see inflorescence
Sessile - see inflorescence
Spike - see inflorescence
Forb - see annual
Peduncle - stalk bearing an inflorescence or a solitary flower (or fruit) on the main stem - Rachis -
central axis bearing a flower or flowers in an inflorescence (spike, raceme or panicle) or a pinna in
a fern blade or pinnately compound leaf - extension of the peduncle in the case of flowers, the
petiole in the case of a compound leaf or the stipe in the case of a fern - Pedicel - stalk bearing a
single flower in an inflorescence - Petiole - stalk that joins a simple or compound leaf blade to the
stem - Pinna - leaflet of a pinnately compound leaf or fern frond - Petiolule - stalk that joins a pinna
to the rachis - Pinnule or Pinnula - leaflet of a pinna in a twice-pinnately compound leaf - Stipe -
stalk that joins a fern blade to the stem - the picture at top right shows the peduncle of
Spotted Water Hemlock - the picture at top middle right shows the pedicel and rachis of an
Enchanter's Nightshade raceme - the picture at top far right shows the rachis, pinna and petiole of
a pinnately compound Mountain Ash leaf - the picture at bottom right shows the rachis, stipe and
pinna of a Bracken Fern frond - the picture at bottom far right shows a close-up of 3 pinnae of
Bracken Fern
central axis bearing a flower or flowers in an inflorescence (spike, raceme or panicle) or a pinna in
a fern blade or pinnately compound leaf - extension of the peduncle in the case of flowers, the
petiole in the case of a compound leaf or the stipe in the case of a fern - Pedicel - stalk bearing a
single flower in an inflorescence - Petiole - stalk that joins a simple or compound leaf blade to the
stem - Pinna - leaflet of a pinnately compound leaf or fern frond - Petiolule - stalk that joins a pinna
to the rachis - Pinnule or Pinnula - leaflet of a pinna in a twice-pinnately compound leaf - Stipe -
stalk that joins a fern blade to the stem - the picture at top right shows the peduncle of
Spotted Water Hemlock - the picture at top middle right shows the pedicel and rachis of an
Enchanter's Nightshade raceme - the picture at top far right shows the rachis, pinna and petiole of
a pinnately compound Mountain Ash leaf - the picture at bottom right shows the rachis, stipe and
pinna of a Bracken Fern frond - the picture at bottom far right shows a close-up of 3 pinnae of
Bracken Fern
Rachis - see peduncle
Petiole, Petiolule - see peduncle
Pinna, Pinnule - see peduncle
Stipe - see peduncle
Pedicel - see peduncle
Annual / Biennial / Perennial - life cycle duration of a plant - an annual plant germinates, flowers
and dies in one year - a biennial plant takes two years to complete its life cycle - in the 1st year, it
produces only leaves low to the ground, often in a rosette - remains dormant over the winter and
flowers in the 2nd year - a perennial plant lives more than two years - herbaceous refers to small
flowering plants (annual, biennial or perennial) that have no persistent woody stem - forb refers toa
herbaceous plant that is not a graminoid (grasses, sedges, rushes) - woody plants are perennial
only, usually referring to shrubs and trees - the picture at right shows 1st year Common Mullein
(biennial) - the picture at far right shows 2nd year Common Mullein
and dies in one year - a biennial plant takes two years to complete its life cycle - in the 1st year, it
produces only leaves low to the ground, often in a rosette - remains dormant over the winter and
flowers in the 2nd year - a perennial plant lives more than two years - herbaceous refers to small
flowering plants (annual, biennial or perennial) that have no persistent woody stem - forb refers toa
herbaceous plant that is not a graminoid (grasses, sedges, rushes) - woody plants are perennial
only, usually referring to shrubs and trees - the picture at right shows 1st year Common Mullein
(biennial) - the picture at far right shows 2nd year Common Mullein
Inflorescence - cluster of flowers or groups of flowers - characterized by the arrangement of flowers
on the peduncle - solitary - only 1 flower on the peduncle - spike - group of sessile (no stalk)
flowers on the rachis - raceme - a spike but the flowers have pedicels - panicle - branched or
compound raceme where each branch has more than 1 flower - umbel - a flat-topped or rounded
raceme where individual flower stalks arise from a common center - characteristic of the Carrot
family - corymb - a raceme where individual flower stalks are of different lengths such that all
flowers are at the same level giving it a flat-topped appearance - head or capitulum - short dense
spike of flowers that appears to be a single flower - characteristic of the Aster family (see
composite) - cyme - a raceme in which the main axis and branches terminate in a single flower -
catkin or ament - a usually hanging spike, most of which are composed of unisexual flowers -
typically found on trees such as willows and cottonwoods - see also spadix for another type of
inflorescence - the pictures at right show the spike of Common Cattail, the raceme of Wild Lupine,
the panicle of False Solomon's Seal, the umbel of Flowering-rush, the cyme of St. John's Wort and
the catkins of Stinging Nettle
on the peduncle - solitary - only 1 flower on the peduncle - spike - group of sessile (no stalk)
flowers on the rachis - raceme - a spike but the flowers have pedicels - panicle - branched or
compound raceme where each branch has more than 1 flower - umbel - a flat-topped or rounded
raceme where individual flower stalks arise from a common center - characteristic of the Carrot
family - corymb - a raceme where individual flower stalks are of different lengths such that all
flowers are at the same level giving it a flat-topped appearance - head or capitulum - short dense
spike of flowers that appears to be a single flower - characteristic of the Aster family (see
composite) - cyme - a raceme in which the main axis and branches terminate in a single flower -
catkin or ament - a usually hanging spike, most of which are composed of unisexual flowers -
typically found on trees such as willows and cottonwoods - see also spadix for another type of
inflorescence - the pictures at right show the spike of Common Cattail, the raceme of Wild Lupine,
the panicle of False Solomon's Seal, the umbel of Flowering-rush, the cyme of St. John's Wort and
the catkins of Stinging Nettle
Leaflet - see peduncle
Bract - modified leaf that performs a specialized function such as attracting pollinators or
protecting young flowers - the picture at right shows the bracts of Field Bindweed - the picture at
middle right shows the bract (called a spathe in this case) of Skunk Cabbage - the picture at far
right shows the bracts of Wild Teasel
protecting young flowers - the picture at right shows the bracts of Field Bindweed - the picture at
middle right shows the bract (called a spathe in this case) of Skunk Cabbage - the picture at far
right shows the bracts of Wild Teasel