An A–Z reference of forestry and botanical terms used in tree identification, measurement, and the descriptions on this site. Some terms cross-reference others — those are linked inline.
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A · B · C · D · E · F · G · H · I · L · M · N · O · P · R · S · T · U · V · W
A
- Achene
- A dry, one-seeded fruit lacking special seams that split to release the seed. The seed coat is attached to the thin, dry ovary wall (husk) by a short stalk.
- Acrid
- Sharp or biting to the taste.
- Acuminate
- Tapering at end to a gradual point.
- Acute
- Terminating in a sharp angle.
- Aggregate fruit
- Cluster of ripened ovaries produced from a single flower containing numerous pistils inserted on a common receptacle. Example: fruit of magnolia or blackberry.
- Alternate
- Not opposite on the axis, but borne at regular intervals at different levels.
- Anther
- Pollen-bearing structure of a stamen.
- Apex
- The tip or end of a bud or leaf — the part opposite the base.
- Apical
- Pertaining to the tip, end, or apex.
- Appressed
- Lying tight or close against.
- Aromatic
- Fragrant; with a pleasing odor.
- Astringent
- Contracting; drawing together.
- Axil
- The upper angle formed by a leaf or branch with a stem.
- Axis
- The central line of an organ; a stem.
B
- Bark
- The outer covering of a trunk or branch.
- Basal
- Pertaining to or situated at the base.
- Berry
- A fruit which is fleshy or pulpy throughout, with several seeds embedded in the pulpy mass.
- Bisexual
- Having both stamens and pistils — that is, both male and female parts.
- Bloom
- A powdery or somewhat waxy substance easily rubbed off. Also: to produce or yield blossoms.
- Bole
- The main axis or trunk of a tree.
- Bract
- Modified leaf subtending a flower or belonging to an inflorescence.
- Bud-scales
- Modified leaves covering a bud.
- Bundle-scars
- Scars on the surface of a leaf-scar. Severed ends of the fibro-vascular bundles that connected the twigs with the leaves.
C
- Calyx
- The outer perianth or floral envelope, usually green in color; sepals, collectively.
- Cambium
- A thin-walled formative tissue between the bark and wood. The active growing portion of the tree.
- Carpel
- A simple pistil, or one member of a compound pistil.
- Capsule
- A dry fruit composed of more than one carpel and splitting open at maturity.
- Catkin
- An ament or spike of unisexual flowers.
- Chambered
- Said of the pith when interrupted by hollow spaces at rather regular intervals.
- Ciliate
- Fringed with hairs on the margin.
- Collateral
- Accessory buds at the side of auxiliary buds.
- Compound
- Composed of two or more similar parts united in a whole.
- Conical
- Cone-shaped.
- Conifers
- A group of trees that usually produce their fruit in the form of a cone or modified cone.
- Coniferous
- Cone-bearing.
- Corolla
- The petals of a flower collectively.
- Cordate
- Heart-shaped.
- Crenate
- Rounded teeth.
- Crown
- The upper mass of branches; also known as the head.
- Cuneate
- Wedge-shaped.
D
- Deciduous
- Falling off, usually at the close of the season.
- Defoliation
- Removal of foliage.
- Dehiscent
- Splitting open at maturity.
- Deliquescent
- Said of the form of a tree with a broad spreading habit. The branches sub-divide until they apparently disappear.
- Deltoid
- Triangular — the Greek symbol for delta.
- Dentate
- Toothed, usually with the teeth directed outwards.
- Diffuse-porous
- Equal-pored. Said of wood when pores in a growth ring are equal in size.
- Dioecious
- Unisexual, with the staminate and pistillate flowers on separate plants.
- Disseminated
- Scattered, thrown, broadcast.
- Divergent
- Pointing away; extending out. Said of buds that point away from the twigs.
- Downy
- Covered with fine hairs.
- Drupe
- A fleshy fruit with a pit or stone, like a cherry.
E
- Elliptical
- Shaped like an ellipse with sloping ends.
- Elongated
- Long, drawn out.
- Entire-margined
- Margin smooth, not cut or toothed.
- Excurrent
- Said of a tree with a continuous trunk and erect habit of growth.
- Exfoliation
- Splitting or cleaving off of outer layers of bark.
- Exotic
- Of foreign origin.
- Exudation
- Oozing out of sap, resin, or other juice.
F
- Fascicle
- A close bundle or cluster.
- Fetid
- Foul smelling.
- Fissures
- Grooves, furrows, or channels, as in the bark.
- Fluted
- Grooved, corrugated, channeled.
- Follicle
- A dry fruit produced from a simple pistil and splitting along one line of suture.
- Fruit
- The ripened ovary of a flower.
G
- Glabrate
- Somewhat glabrous, or becoming glabrate.
- Glabrous
- Smooth, without hairs.
- Glandular
- Bearing glands or gland-like.
- Glaucous
- Covered with a bluish or whitish waxy coating; a bloom.
- Globose
- Ball-like or nearly so.
- Globular
- Ball-like.
H
- Habitat
- Site or place of growth.
- Hardwood
- A collective term for broadleaved trees, the wood of which may or may not be dense.
- Heartwood
- The physiologically dead, central, usually darker colored portion of the tree trunk.
- Hybrid
- A crossbreed of two species.
I
- Increment
- Growth; increase.
- Incised
- Divided into lobes separated by narrow or acute sinuses that extend halfway or more to the midrib.
- Indehiscent
- Applied to fruits that do not split open to discharge the seeds, remaining closed at maturity.
- Indigenous
- Applied to plants that are native to a certain locality. Not introduced.
- Intolerant
- Not shade-enduring. Requiring sunlight.
- Involucre
- A cluster of bracts subtending a flower.
L
- Lamina
- The blade or flattened portion of a leaf.
- Lanceolate
- Shaped like a lance; several times longer than wide, growing to a point.
- Lateral
- Situated on the side, as the buds along the side of the twig.
- Leaflets
- One of the small blades or divisions of a compound leaf.
- Leaf-scar
- The scar left after a leaf falls.
- Lenticel
- A corky growth on young or sometimes older bark, which admits air to the interior of the twig or branch.
- Linear
- Line-like, long and narrow, with parallel edges.
- Lobed
- Said of leaves that have the margins more or less cut or divided.
M
- Medullary
- Pertaining to the pith or medulla.
- Medullary Ray
- Radial lines of tissues crossing the growth rings at right angles and extending into the bark.
- Midrib
- The central or main rib or vein of a leaf.
- Monoecious
- Bearing male and female flower parts in separate flowers on the same plant.
- Mucilaginous
- Slimy or gummy when touched or chewed.
- Multiple fruit
- A cluster of fruits of separate flowers crowded together and forming what appears to be a single fruit. Examples: mulberry, strawberry, Osage-orange fruits.
N
- Naked
- Said of buds without scales, and seeds without a covering.
- Naval Stores
- Refers to tar, turpentine, resin, etc.
- Node
- A place on a twig where one or more leaves originate.
- Nut
- A dry, one-seeded fruit with a hard indehiscent covering, encased partly or wholly in an involucre or husk.
- Nutlet
- A small nut.
O
- Oblique
- Slanting, uneven. Uneven-sided.
- Oblong
- About twice as long as wide, sides nearly parallel.
- Obovate
- Reversed egg-shaped.
- Obtuse
- Not sharp or pointed; blunt; greater than 90 degrees and less than 180 degrees — an obtuse angle.
- Opposite
- Said of leaves and buds directly across from each other.
- Orbicular
- Circular.
- Oval
- Rounded.
- Ovate
- Egg-shaped.
- Ovoid
- Egg-shaped or nearly so.
P
- Palmate
- Radiately lobed or divided from the petiole; hand-like, as leaflets of buckeye.
- Panicle
- A loose, irregularly compound flower cluster with flowers on pedicels.
- Pedicel
- The support or stem of a single flower or fruit in a cluster.
- Peduncle
- A primary flower stalk supporting a cluster of flowers or a solitary flower — later the fruit. A fruit-stem.
- Perennial
- Lasting for more than one year.
- Persistent
- Remaining after blooming, fruiting, or maturing.
- Petiole
- The stalk of a leaf.
- Pinnate
- Featherlike, with leaflets on both sides of rachis or leaf stalk.
- Pistil
- Female seed-bearing organ of a flower. May consist of stigma, style, and ovary.
- Pith
- The soft central part of a twig or stem.
- Pod
- Any dry, one-chambered, dehiscent fruit.
- Pollen
- The dust-like substance from the anthers of a flower.
- Pollination
- The process of bringing the pollen of the male flower in contact with the stigma of the female flower.
- Pome
- A fleshy fruit with a core, such as an apple or pear.
- Porous
- With open tubes (through wood).
- Prickle
- A sharp-pointed, needle-like outgrowth.
- Pubescent
- With short, soft, down-like hairs.
- Pungent
- Acrid or sharp to smell.
- Pyramidal
- Shaped like a pyramid with the broadest part near the base.
R
- Rachis
- The stalk supporting the leaflets of a compound leaf.
- Resin-ducts
- A passage for the conduction of resin found in the leaves and wood.
- Ring-porous
- Said of wood that has pores of unequal size — the larger ones found in the spring wood and the smaller ones in the summer wood.
S
- Samara
- An indehiscent winged fruit, such as that of a maple.
- Sapwood
- The recently formed, usually light-colored wood lying outside of the heartwood.
- Scabrous
- Rough, with stiff, bristly hairs.
- Scales
- The small, modified leaves that protect the growing point of a bud, or the part of a cone that bears the seeds. Also: the small flakes into which the outer bark of a tree divides.
- Scurfy
- Covered with small bran-like scales.
- Serrate
- Having sharp teeth on the margin.
- Sessile
- Seated; without a stalk.
- Sheath
- A tubular envelope or covering, such as those that surround the base of pine needles.
- Silky
- Covered with long, soft, straight, fine hairs.
- Simple
- Consisting of a single part; not compound.
- Sinus
- The cleft or opening between two lobes.
- Sinuate
- Wavy.
- Softwood
- A general term given to conifers, the wood of which may or may not be of low density.
- Stamen
- Male reproductive organ of a flower. Consists of a pollen-bearing anther on a filament.
- Stipule
- A leaf-appendage at the base of the leaf-stalk.
- Stipule-scar
- The scar left by the fall of the stipule.
- Stolon
- A runner or basal branch that may take root.
- Striate
- Marked with fine elongated ridges or lines.
- Striations
- Long narrow lines or ridges.
- Strobile
- A fruit marked by overlapping scales, as in pines, birches, etc.
- Sucker
- A shoot arising from an underground bud.
- Superposed
- Said of buds when they are arranged one above the other.
- Symmetrical
- Regular as to the number of parts. Having the same number of parts in each circle.
T
- Terminal
- Located at the outer end.
- Thorn
- A stiff, woody, sharp-pointed projection, as found on locust; a spine.
- Tolerant
- Applied to trees that endure certain factors, particularly shade.
- Tomentose
- Densely pubescent; hairy. Covered with matted hairs.
- Tomentum
- A dense layer of woolly hairs.
- Truncate
- Ending abruptly, as if cut off at the end.
- Tufted
- Growing in clusters.
U
- Unisexual
- Consisting of one sex only, either staminate or pistillate.
V
- Valvate
- Said of buds in which the scales merely meet without overlapping. Also: fruit opening by valves.
- Veins
- Threads of fibro-vascular tissue in leaves or other organs.
W
- Whorl
- A group of three or more similar organs, such as leaves or buds, arranged about the same place of attachment.
- Whorled
- Borne in a whorl.
Source
This glossary is drawn from Forest Trees of Texas, How to Know Them by Wilbur R. Mattoon — Bulletin 20 of the Texas A&M Forest Service, eighth edition. Republished with permission from the Texas A&M Forest Service for educational purposes.