Tree & Botanical Glossary

Term Definition
Achene small, dry and hard one-seeded fruit.
Acorn nut-like fruit of an oak with a scaly or warty cap.
Alternate leaves leaves arranged on alternating sides of the twig.
Angiosperm class of plants that has the seeds enclosed in an ovary; includes flowering plants.
Annual rings a layer of wood – including spring-wood and summer-wood – grown in a single season; best seen in the cross-section of the trunk.
Awl-like leaves short leaves that taper evenly to a point; found on junipers and redcedars.
Berry fleshy fruit with several seeds.
Bisexual flower a perfect flower; a flower with organs of both sexes present.
Broadleaf trees having broad, flat-bladed leaves rather than needles; also a common name for hardwoods.
Cambium layer of tissue one to several cells thick found between the bark and the wood; divides to form new wood and bark.
Capsule dry fruit that splits open, usually along several lines, to reveal many seeds inside.
Chambered pith pith divided into many empty horizontal chambers by cross partitions.
Common name familiar name for a tree; can be very misleading because common names vary according to local custom, and there may be many common names for one species.
Compound leaves leaves with more than one leaflet attached to a stalk called a rachis.
Conifer trees and shrubs that usually bear their seeds in cones and are mostly evergreen; includes pines, firs spruces, yews and Douglas Fir.
Cross-section surface or section of tree shown when wood is cross-cut; shows the circular growth rings.
Deciduous leaves leaves that die and fall off trees after one growing season.
Dichotomous key a key to tree identification based on a series of decisions, each involving a choice between two alternate identification characteristics.
Diffuse-porous a type of hardwood in which vessels in the spring-wood are the same size as vessels in summer-wood (maples, birches, poplars, etc.).
Dioecious having unisexual flowers with staminate (male) and pistillate (female) flowers borne on different trees.
Drupe fleshy fruit with a single stone or pit.
Elliptic resembling an ellipse and about one-half as wide as long.
Entire margin leave margins that are smooth (not toothed).
Evergreen trees and shrubs that retain their live, green leaves during the winter and for two or more growing seasons.
Family group of closely related species and genera; scientific name ends in "aceae".
Forest ecology study of the occurrence of forest plants and animals in respect to their environment.
Genus a group of species that are similar; the plural of genus is genera.
Glabrous Smooth, with no hair or scales.
Gymnosperm large class of plants having seeds without an ovary, usually on scales of a cone; includes conifers and the ginkgo.
Hardwoods usually refers to trees that have broad-leaves and wood made up of vessels; similar to angiosperms.
Heartwood nonliving wood (often dark) found in the middle of a tree's stem.
Imperfect flower a unisexual flower with either functional stamens or pistils but not both.
Inflorescence the flowering portion of a plant.
Lanceolate lance-shaped; about 4 times as long as wide and widest below the middle.
Lateral buds buds found along the length of the twig (not at the tip); they occur where the previous year's leaves were attached.
Leaflets small blades of a compound leaf attached to a stalk (rachis); without buds where they attach.
Legume fruit that is a dry, elongated pod that splits in two, with seeds attached along one edge inside.
Lobed margin leaf margin with gaps that extend more or less to the center of the leaf.
Lustrous glossy, shiny.
Monoecious having unisexual flowers with staminate (male) and pistillate (female) flowers borne on the same tree, though often on different branches.
Multiple fruit fruit made up of a cluster of ripened ovaries that came from many separate flowers attached to a common receptacle.
Naturalized nonnative trees that have escaped cultivation and are growing in the wild.
Needle-like leaves very thin, sharp, pointed, pin-like leaves; found on pines, firs and some other softwoods.
Node the point on a stem at which leaves and buds are attached.
Nut hard, dry fruit with an outer husk that sometimes does not split open readily and an inner shell that is papery to woody.
Obovate inversely ovate.
Opposite leaves leaves arranged directly across from each other on the twig.
Orbicular circular in outline.
Oval broadly elliptic, with the width greater than one-half the length.
Ovate having the lengthwise outline of an egg, widest below the middle.
Palmately compound compound leaves in which several leaflets radiate from the end of a stalk (rachis); like the fingers around the palm of a hand.
Perfect flower a bisexual flower with functional stamens and pistils.
Persistent leaves leaves that remain on the tree during winter.
Petiole a slender stalk that supports a simple leaf.
Phloem inner bark of a tree that carries food and sugars from the leaves to other parts of the tree.
Photosynthesis process through which the leaves, with energy from sunlight, make food from water and carbon dioxide.
Pinnately compound compound leaves in which leaflets are attached laterally along the rachis or stalk; leaves may be once, twice, or three-times pinnately compound.
Pistil the ovary-bearing (female) organ of a flower.
Pistillate flower a unisexual (female) flower bearing only pistils.
Pith soft and spongy, or chambered tissue found in the middle of the stem.
Polygamo-dioecious having unisexual flowers with staminate (male) and pistillate (female) flowers borne on different trees, but also having some perfect flowers on each tree.
Polygamo-monoecious having unisexual flowers with staminate (male) and pistillate (female) flowers borne on the same tree, along with some perfect flowers on each tree.
Polygamous Having some unisexual flowers and some bisexual flowers on each plant (can be polygamo-monoecious or polygamo-dioecious).
Pome fruit with a fleshy outer coat and a stony layer (similar to plastic) within, with seeds inside the stony layer (apples, pears, etc.).
Pubescent covered with hairs.
Rachis the central stalk to which leaflets of a compound leaf are attached.
Radial-section surface or section of a tree shown when wood is cut down its length straight through the middle.
Rays ribbon-like groups of vessels, tracheids and fibers that move water and other substances in the xylem between inner and outer rings and the phloem; best seen in radial sections of the trunk.
Rhombic with an outline resembling a rhombus (diamond-shaped).
Ring-porous type of hardwood in which the vessels in spring-wood are much larger than vessels in summer-wood (oaks, ashes, elms etc.).
Samara dry fruit with one or two flat wings attached to a seed (as on elms and maples).
Sapwood living wood, often light colored, found between the bark or cambium and the heartwood, usually darker colored.
Scale-like leaves small, short, fish-scale-like leaves which cover the entire twig; found on juniper and redcedar.
Scientific names Latin-based names used world-wide to standardize names of trees and other plants and animals.
Semi-ring-porous type of hardwood in which the vessels in the spring-wood are somewhat larger than vessels in summer-wood; between diffuse-porous and ring-porous (black cherry, black walnut, etc.).
Serrate with teeth.
Shade intolerant trees that need a lot of sunlight for growth and survival.
Shade tolerant trees that can tolerate less sunlight for growth and survival.
Shrub low-growing woody plant with many stems rather than one trunk.
Simple leaves leaves with one blade attached to a petiole, or stalk.
Sinus a recess between two lobes.
Softwoods usually refers to trees that are conifers or cone-bearing; conifers generally have softer wood than angiosperms or hardwoods, but there are many exceptions.
Solid pith pith that is not divided into chambers.
Species trees with similar characteristics and that are closely related to each other; species is used in both the singular and plural sense (specie is not proper).
Spring-wood wood on the inside of an annual ring, formed during the spring; cells are often thinner-walled.
Stamen the pollen-bearing (male) organ of a flower.
Staminate flower a unisexual (male) flower bearing only stamens.
Strobile a cone or inflorescence with overlapping bracts or scales.
Summer-wood wood on the outside of an annual ring, formed during the summer; this wood is sometimes dark and cells are often thicker-walled.
Tangential-section surface or section of a tree shown by cutting a tree lengthwise, but not through the middle.
Tepal A usually showy part of the outer portion of a flower that is not differentiated into a sepal or petal.
Terminal buds bud appearing at the apex, or end, of a twig; usually larger than other lateral buds.
Toothed/serrated margin leaf margin with coarse, fine, sharp or blunt teeth.
Tracheids small-diameter tubes in the wood of trees that carry water from the roots to the leaves; water carrying tubes in conifer xylem are all tracheids.
Tree a woody plant with one to a few main stems and many branches; usually over 10 feet tall.
Unisexual flower an imperfect flower; a flower with organs of only one sex present.
Vessels large-diameter tubes in the wood of hardwood, or angiosperm, trees that carry water from the roots to the trees
Xylem the wood of a tree, made up of strong fibers, tracheids and vessels.