| 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. |
