Plant structural groups

Definition

Annual

Complete their life history from seed to seed during one growing season.

Aquatic

Perennating organs under water; leaves submerged or floating (hydrophytes). Also plants that have their perennating organs in soil or mud below water level with aerial shoots above water level (helophytes).

Climber

Climbing species use other plants or rocks and man-made structures for support. Released from the function of holding up the plant shoots, the stems possess little or no ability to bear any weight, but instead they are very flexible and have considerable tensile strength. Extremely rapid growth of shoots; can be herbaceous or woody; relatively narrow stems versus leaf area, less than a shrub or tree with the same leaf area; woody stems are very flexible to permit bending, twisting, and coiling, often with patches of soft tissue alternating with the harder tissues.

Erect Perennial

Those species that are upright in appearance and have life history from seed to seed lasting more than two years, but could not be classed as either shrubs or trees.

Glabrous Perennial

Species devoid of hairs and with a life history from seed to seed lasting more than two years.

Herbaceous Perennial

Green and more or less succulent species with a life history from seed to seed lasting more than two years. Including moss, ferns, hemicryptophytes (perennating buds located at ground level; the above ground parts die back at the onset of unfavorable conditions), and geophytes (persist below ground over unfavorable seasons as rhizomes, bulbs or tubers (excluding Orchids) from which arise the buds to produce the next season’s aerial shoots.

Low Shrub Layer

Woody; perennial; erect, procumbent or weeping; foliage occupies all or part of total plant height; multiple stems and branches arising from a rootstock or very short common trunk; generally 0–2 m.

Orchid

Of the family Orchidaceae. Often persist below ground as tubers during unfavorable seasons from which arise the buds to produce the next season’s aerial shoots.

Perennial

Life history from seed to seed lasting more than two years. Not specifically herbaceous, erect, or glabrous.

Tall Shrub Layer

Woody; perennial; erect, procumbent or weeping; foliage occupies all or part of total plant height; multiple stems and branches arising from a rootstock or very short common trunk; generally 5–8 m.

Shrub Layer

Woody; perennial; erect, procumbent or weeping; foliage occupies all or part of total plant height; multiple stems and branches arising from a rootstock or very short common trunk; generally 2–5 m tall.

Tree

Woody; perennial; canopy raised well above the ground. Depth of canopy usually less than or equal to two thirds of the total tree height. Single stemmed, or if multi-stemmed, fewer than five individual trunks resulting from branching of a single short trunk. Height usually >5m, predominantly >8m. Grass and Sedge Layer. May be perennial or annual; <30% foliage cover of tallest stratum (sparse to very sparse); generally 0–2 m in height.