Botanical Dictionary
Fern Terminology
Blade
The green, leafy part of the frond
Synonym: lamina
Costa
Midvein of the fern's pinna
Fertile blade
A blade bearing spores and often differing markedly in color, form, and size from the sterile blade
Fertile frond
A frond bearing spores and often differing markedly in color, form, and size from the sterile fronds
Fiddlehead
Emerging frond of a fern that is curled
Indusium
Specialized, protective flap of tissue covering the sorus that protects the developing sporangia of tissue covering the sorus that protects the developing sporangia.
Pinna
Fully separated subdivision of the blade that is attached to the rachis. Only applies to pinnate (fully divided blades), not just lobed.
Pinnae is plural of pinna.
Synonyms: leaflet
Pinnule
Fully separate subdivision of the pinna. This term is applied when the pinna is fully divided (not just lobed).
Rachis
Central axis of the blade that bears the pinnae (main leaves). The stipe and the rachis make up the whole axis (stem) of the frond.
Rhizome
Part of the stem of the fern that produces roots below and fronds above. Rhizomes can be thick, short and almost buried underground or long, narrow, growing horizontally just below or along the ground's surface.
Are often covered with scales or hairs. Rhizomes are perennial and are alive underground even when all the fronds of the fern have died.
Synonyms: rootstock, trunk
Sorus
A cluster of sporangia usually occurring on the underside or margins of the leaflets. Start green and turn brown at maturity.
May appear distinct on the leaflet or massed together.
Sporangium
A small thin-walled capsule that bears the spores.
Sporocarp
A specialised structure in aquatic ferns whose primary function is production and release of spores
Sterile frond
A sterile frond lacks spores, is green, and does most of the photosynthesizing.
Stipe
Part of the fern leaf above the ground, arising from the rhyzome below the point where the fern's blade starts to form.
Synonyms: stalk, stem, petiole.
Vein
Elongated cells, most visible on the leafy parts that transport essential nutrients and sugars.
Leaf Terminology
Arrangement
Alternate
Leaves are attached to the stem singly, not in opposite pairs.
Basal
Leaves attached at the base of a stem in a tight cluster.
Opposite
Leaves attached in pairs to each side of a twig or a shoot.
Perfoliate
A leaf with the margins entirely surrounding the stem so that the stem appears to pass through the leaf.
Whorled
Arranged along a twig or shoot in groups of three or more at each node.
General
Cotyledon
Seed leaf (first leaf or first pair of leaves when plant germinates)
Leaf Apices
Acuminate
Gradually tapering to a sharp point and forming concave sides along the tip
Cuspidate
Tipped with a short, sharp, abrupt point
Emarginate
With a notch at the apex
Leaf Parts
Apex
The tip of the leaf, the point farthest from attachment.
Blade
The broad part of the leaf.
Leaflet
One of the leaflike parts of a compound leaf.
Midvein
The central vein of a leaf.
Petiole
The leaf stalk
Stipule
A small leaflike appendage to a leaf, usually borne in pairs at the base of the leaf stalk.
Tendril
A slender, twining organ used to grasp support for climbing.
Margin
Bidentate
Apex with two teeth or lobes
Cleft
Cut or split about half-way to the middle or base
Crenate
Margins with continuous, rounded, and generally outward-pointing teeth; dentate with conspicuously rounded teeth.
Crenulate
Very small rounded teeth along the margins.
Dentate
Margins with continuous, generally outward-pointing teeth.
Denticulate
Dentate with very small teeth.
Entire
Margins without teeth or serrations.
Incised
Cut sharply, deeply and usually irregularly
Serrate
Margins with continuous, sharp, forward-pointing teeth, like the blade of a ripsaw.
Serrulate
Toothed along the margin with minute,sharp, forward-pointing teeth.
Sinuous or sinuate
Margins with more or less wavy or sinuous structure in the plane of the leaf.
Toothed
Margins more or less toothed. The term is generic and encompasses the terms serrate, dentate, and crenate, which describe different types of relatively fine, continuous toothing, as well as situations where the teeth are widely spaced, large and lobe-like, or occur at different scales (doubly toothed).
Tripartite
Leaf three-parted
Undulate
Margins wavy or undulating out of the plane of the leaf.
Shape
Auriculate
When a simple leaf divided at the base into two leaf-like appendages
Cordate
Heart-shaped, with the notch at the base.
Cuneate
Narrowly triangular, wider at the apex and tapering toward the base
Elliptical
Leaves shaped like an ellipse; that is, generally symmetrical, elongated, and more or less evenly rounded at both ends.
Hastate
Arrowhead-shaped, but with the basal lobes turned outward rather than downward; halberd-shaped.
Lanceolate
Shaped like a lance head; tapering to a point on each side, long.
Synonyms
lance-shaped
Linear
Resembling a line; long and narrow with more or less parallel sides.
Obcordate
Inversly cordate, with the attachment at the narrower end
Oblong
Two to four times longer than broad with nearly parallel sides.
Obovate
Inversely ovate, with the attachment at the narrow end.
Orbicular
Circular or rounded. The overall shape of the leaf is rounded or orb-like.
Oval
Broadly elliptic, the width over one-half the length
Ovate
Egg-shaped in outline and attached at the broad end.
Peltate
Shield-shaped; borne on a stalk attached to the lower surface rather than to the bae or margin.
Pinnatifid
Pinnately divided, but not all the way down to the central axis
Reniform
Leaf is kidney-shaped
Sagittate
Arrowhead-shaped, with the basal lobes directed downward.
Structure
Bipinnately Compound
Compound leaf where each leaflet is itself pinnately compound, forming a secondary set of leaflets
Synonyms
bipinnate
Compound
A leaf separated into two or more leaflets.
Connate
Two leaves joined at the base
Dissected
Deeply divided into many narrow segments.
Lobed
Leaves with distinct protrusions (lobes), either rounded or pointed and cut less than half-way to the base or midvein.
Palmate
Lobed, veined, or divided from a common point like the fingers of a hand.
Palmately Compound
A compound (with several leaflets) leaf that is palmate
Pinnately Compound
A compound leaf with leaflets arranged on opposite sides of an elongated axis. This includes bipinnate and tripinnate leaves.
Synonyms
pinnate
Simple
Leaf-blade is not separated into leaflets, though the blade may be deeply lobed or toothed.
Tripinnately Compound
Compound leaf where the leaflets are divided yet again, forming a tertiary set of leaflets
Synonyms
tripinnate
Venation
Palmate veins
Venation pattern where several main veins radiate from one point where the petiole and leaf blade unite
Parallel veins
Venation pattern where the veins run parallel except where they meet at the tip and the base.
Pinnate Veins
Venation pattern where the main vein extends from the base to the top of the leaf. Smaller veins are produced from the main vein.
Flower Terminology
Flower parts
Carpel
Female reproductive organ of a flower consisting of stigma, style, and ovary.
Hypanthium
A structure where basal portions of the
Labellum
Central petal at the base of an orchid flower
Perfect
Flower that has both male and female parts
Perianth
The calyx and corolla of a flower, collectively, especially when they are similar in appearance.
Pistil
The female reproductive organ of a flower, typically consisting of a stigma, style, and ovary (called a carpel) or several carpels fused together.
Pistillate
The female flower(s)
Stamen
The male reproductive organ of a flower, consisting of an anther and filament; the angiosperm microsporophyll.
Staminate
The male flowers
Flower symmetry
Actinomorphic
Radially symmetrical, so that a line drawn through the middle of the structure along any plane will produce a mirror image on either side.
Zygomorphic
Bilaterally symmetrical, so that a line drawn through the middle of the structure along only one plane will produce a mirror image on either side.
General
Regular
Flowers that are radially symmetrical
Unisexual flower
A flower that is either male (staminate) or female (pistillate).
Inflorescence Terminology
General
Axillary
Arises from a leaf axil
Synonyms
axillary inflorescence
Terminal
Terminates the growth of the branch
Synonyms
terminal inflorescence
Infloresence Parts
Bract
Modified/specialized, usually small, leaflike structure often positioned beneath a flower or inflorescence. Often confused with flower petals.
Disk
The central portion of the involucrate head bearing tubular or disk flowers in the Asteraceae.
Floret
A small flower; an individual flower within a dense cluster, as a grass flower in a spikelet, or a flower of the Asteraceae in an involucrate head.
Flower
The reproductive portion of the plant consisting of stamens, pistils, or both, and usually including the perianth of sepals or both sepals and petals.
Involucre
A whorl of bracts subtending a flower or flower cluster.
Pedicel
The stalk of a single flower in an inflorescence, or of a grass spikelet.
Peduncle
The stalk of a solitary flower or of an inflorescence.
Ray
1. An inflorescence branch in an umbel.
2. Petal-like parts in the ray flowers of Asteraceae.
Spathe
A large bract or pair of bracts forming a sheath to enclose the flower cluster of certain plants such as Jack-in-the-Pulpit.
Infloresence Types
Catkin
An inflorescence consisting of a dense spike or raceme of apetalous, unisexual flowers.
Corymb
A flat-topped or round-topped inflorescence, racemose, but with the lower pedicels longer than the upper.
Cyme
A flat-topped or round-topped determinate inflorescence, in which the terminal flowers bloom first.
Synonyms
cymose
Head
A dense cluster of sessile or subsessile flowers; the involucrate inflorescence of the Asteraceae.
Panicle
A branched, racemose inflorescence with flowers maturing from the bottom upwards.
Synonyms
paniculate
Raceme
An unbranched, elongated inflorescence with pedicellate flowers maturing from the bottom upwards
Spadix
A spike with small flowers crowded on a thickened axis.
Spike
An unbranched, elongated inflorescence with sessile or subsessile flowers or spikelets maturing from the bottom upwards.
Umbel
A flat-topped or convex inflorescence with the pedicels arising more or less from a common point, like the struts of an umbrella; a highly condensed raceme.
Conifers Terminology
Pollen Cone
Male reproductive organ, produces pollen
Synonyms
male cone, male strobilus
Seed Cone
Female reproductive organ containing seeds (after pollination) under the scales
Synonyms
female cone, female strobilus, ovulate cone
Strobilus
Reproductive structures of conifers; cone-shaped structures of either ovule-bearing (female) or spore-bearing (male) scales or bracts
Fern allies terminology
Clubmosses
Annual constriction
The term describes a section of stem that looks narrower than the rest of the stem due to presence of smaller and occasionally also more congested leaves. These indentations mark the start of each seasonal growth.
Appressed
Leaf is lying close to or pressed against the stem or stipe.
Ascending
Leaf is growing at an upward angle relative to the stem.
Rank
When looking down along the stem, you notice that the leaves line up in rows or ranks. If a pair of leaves is positioned at the 90-degree angle with respect to the pair above or below, then the leaves are 4-ranked. In case every three pairs of leaves are offset from each other, the leaves are 6-ranked.
Reflexed
Leaf bent backward relative to the stem
Sporophyll
Specialized leaf bearing a sporangium.
Spreading
Leaf is at an angle from ascending to perpendicular to the stem.
Strobilus
A cone, that is, a region of the stem that bears only specialized leaves - sporophylls.
Firmosses
Gemmae
Produced in the upper portion of mature stems.
Stomates
Air pores on the surface of leaves.
Horsetails
Cavity
Large, hollow center in the stem or branches.
Cone
Each fertile stem forms a spore-bearing cone at the top, which consists of an axis and specialized leaves (also called scaled) bearing sporangia (spore cases).
Internode
Stem or branch section between the nodes.
Node
A swollen, solid(not hollow) area of the stem; also, point where branches attach to the stem.
syn: joint
Rhizome
Underground organs structurally similar to stems and branches, ranging in length from a few inches to many feet, spreading extensively, with new stems or rootles sprouting from their nodes.
Ridge
Elevated lines on the surface of stems/branches and separated by grooves.
Sheath
Generally, a tubular part of a leaf enclosing the stem. In a horsetail, tiny modified leaves are whorled at each node and fused at edges, collectively forming a cylindrical toothed sheath.
Fruit Terminology
Fruit types
Achene
A dry fruit that does not separate or split open when mature, formed from one carpel and containing a single seed.
Acorn
The hard, dry fruit of oaks with a single large seed and a cuplike base.
Berry
A fleshy fruit developing from a single pistil, with several or many seeds, such as tomato. Sometimes applied to any fruit which is fleshy or pulpy throughout, i.e. lacking a pit or core.
Bur
A fruit armed with barbed or hooked spines or appendages.
Drupe
An indehiscent fruit in which an outer fleshy part surrounds a single shell (for example the bit) of hardened endocarp with a seed (kernel) inside.
Follicle
Dry unilocular fruit formed from one carpel
Legume
A dry, dehiscent fruit derived from a single carpel and usually opening along two lines of dehiscence as in a pea pod.
Samara
A dry, indehiscent, winged fruit, such as in maples
General
Aril
A specialized outgrowth from a seed that partly or completely covers the seed
Dehiscent
Splits open to release seeds when ripe
Indehiscent
Does not split open to release the seeds when ripe
General Terminology
Angiosperm
Plants that produce flowers and bear their seeds in fruits
Dioecious
A species having male and female reproductive organs on separate plants
Glabrous
Surface devoid of hair or pubescence
Gymnosperm
Plants that produce naked seeds without fruits, such as conifers.
Inflorescence
A part of plant that bears flowers in a group (may include bracts and inflorescence branches in addition to flowers).
Monoecious
A species having male and female reproductive organs on the same plant
Node
Point of attachment of a leaf, peduncle or branch to a stem.
Pilose
Covered with long soft hairs
Puberulent
Plant surfaces covered with very fine, short, soft hairs
Pubescent
1. Covered with short, soft hairs.
2. Bearing any kind of hairs.
Rhizome
Horizontal underground plant stem capable of producing the shoot and root systems of a new plant.
syn: creeping rootstalk
Scabrous
Rough to the touch due to the structure of the epidermal cells or presence of short stiff hairs.
Scape
Sessile
Flowers or leaves that have no stalk and are borne directly on the stem or peduncle.