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. |