Alternate leaf arrangement — Leaves are arranged along the stem with only one leaf at each node.
Annual — A plant that completes its lifecycle in 12 months or less.
Basal (leaf) — At or near the base of a plant or the base of a branch or trunk.
Biennial – A plant that germinates and produces foliage and roots during its first growing season, then produces flowers and seeds and dies during its second growing season.
Bract – A modified leaf, usually small, but sometimes large and brightly colored, growing at the base of a flower cluster. Bracts are sometimes mistaken for petals in plants such as dogwoods and poinsettias.
Bulb – An underground storage organ consisting of a thin, flattened stem surrounded by layers of fleshy leaf bases. Roots are attached to the bottom.
Calyx – The collective term for the sepals. (See also Sepal.)
Catkin – Flowers clustered in a spike, usually pendulous.
Compound (leaf) – A leaf in which the blade is subdivided into two or more sections called leaflets. (See also Simple [leaf].)
Crown – A short, compressed stem to which leaves and roots are attached.
Cultivar – A cultivated variety of a species.
Deciduous – A plant that sheds all of its leaves annually.
Dioecious – A plant species having separate male and female flowers on separate plants.
Drupe / Drupelets – A fleshy fruit with a hard, inner layer that surrounds the seed. Also known as stone fruit. A drupelet is a very small stone fruit.
Epiphytes / Epiphytic – A plant that grows on another plant but is not a parasite.
Evergreen – A plant that retains some or all of its foliage year-round.
Fronds – Specifically the foliage of ferns but often applied to any foliage that looks fern-like, such as palm leaves.
Globose – Ball-shaped.
Herbaceous – A soft, pliable stem that dies back to the ground at the end of the growing season.
Involucre – A cluster of bracts.
Leaflet – An individual sub-unit of a subdivided leaf.
Lenticels – A small opening on the surface of fruits, stems, trunks, and roots that allows the exchange of gases between internal tissues and the atmosphere.
Lobes – Projections on the edge of a leaf.
Midrib / Midvein – A large vein in the middle of a leaf.
Nodes / Internodes – The point on a plant where a stem, bud, or leaf develops. The space on the stem between nodes is an internode.
Obovate – An oval shape that is narrower at the base than the tip.
Opposite leaf arrangement – Leaves are arranged along the stem with two leaves at each node.
Palmately – Radiating outward from a single point, somewhat like the fingers of a hand. A term used to describe the arrangement of leaflets in some compound leaves and the arrangement of veins within a leaf blade.
Perennial – A plant that lives three or more years.
Petiole – The stalk that attaches the blade of a leaf to the stem.
Pinnae – An individual sub-unit of a subdivided frond.
Pinnate / Bipinnate – Radiating outward from a central axis, somewhat like the divisions of a bird feather. Terms used to describe the arrangement of leaflets in some compound leaves and the arrangement of veins within a leaf blade.
Propagated – Started new plants by cutting, seeding, layering, grafting, dividing, etc.
Rhizome – A horizontal underground stem.
Rosette leaf arrangement – A small cluster of leaves radially arranged in an overlapping pattern attached to a short, compressed stem on plants such as dandelions.
Scalloped – Shallow, curved teeth similar to the edge of a scallop shell.
Sepal – The outermost flower part, typically green or greenish and more or less leafy in appearance. Sepals enclose the other parts of the flower within a flower bud.
Sheathing – A protective cover.
Simple (leaf) – A leaf that is not divided into separate pieces.
Species – The basic unit of plant classification.
Spur – On fruit trees, a short, compact twig on which flowers and fruit are borne. In flowers, a hollow extension of a petal.
Stamen – The male, pollen-producing part of a flower.
Succulent – A type of plant with thickened stems and leaves for storing water. Fleshy and tender with regard to new growth.
Tendrils – A slender projection from a stem used for clinging or climbing, usually a modified leaf. Examples include grapes, clematis, peas, and cucumbers.
Terrestrial – Growing in soil rather than in the air or on the bark of trees.
Tuberous (root) – A modified root enlarged for storage of food reserves found in dahlias and sweet potatoes, for example.
Umbels – A flower cluster in which stalks are of nearly equal length from a common center, similar to an umbrella shape.
Whorled leaf arrangement – Leaves are arranged along the stem with three or more leaves at each node.
Woody – A plant that produces hard (rather than fleshy) above-ground stems that survive winter and continue to grow in diameter each year. Examples include trees, shrubs, and some vines.