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Glossary of plant terms

Search our dictionary of 3,300 botanical and plant-related terms – the largest online.
Or browse the descriptions and definitions using the A-Z.

uber

Means "luxuriant - fruitful" in Latin.

uliginosus

Means "of swamps or marshes" in Latin.

ultraviolet radiation

This is electromagnetic radiation that has wavelengths between the visible and X-ray regions of the spectrum. It has generally harmful effects on plant and animal life (leading to skin cancers in humans). The ozone layer is an important part of the Earth's defence against potentially harmful ultraviolet radiation from the sun. Damage to the ozone layer due to the release of certain pollutant gases such as methyl-bromides and chlorofluorocarbons, results in increasing ultraviolet radiation.

umbel

A flower cluster with stalks arising from the same point (like an umbrella).

umbellate

Having flowers in umbels.

umbellatus

Means "umbrella-like clusters" in Latin.

umbellifer

A member of the carrot family with flowers in umbels.

umbraculiferous

Refers to a leaf or flower that is shaped like an umbrella.

umbrosus

Means "shade loving" in Latin.

uncinate

Refers to a plant organ which is "hook-shaped".

uncinatus

Means "hooked" in Latin.

undergrowth

Generally refers to a mix of plants which may grow below a canopy of trees or large shrubs.

underplanting

Refers to the planting of spring bulbs, shrubs etc beneath a canopy of trees or other plants.

undershrub

A woody perennial, rarely as tall as 1 metre high, and often more or less prostrate.

understorey

Refers to the layer of plant growth beneath a tree canopy.

undifferentiated growth

This describes the division of cells in a tissue where no clear distinction into tissue types results. An example being a burr which is a woody outgrowth on the stems of certain trees resulting in swirls of woody tissues, which are prized by woodcarvers for their decorative effects.

undulate

Wavy in a plane at right angles to the surface.

undulatus

Means "wavy - hooked" in Latin.

unicellular

Single-celled.

union

A simple term for a graft union.

unisexual

Having only one sexual type, usually with reference to flowers.

urbicus

Means "of towns" in Latin.

urceolate

Meaning "urn-shaped".

urceolatus

Means "urn-shaped" in Latin.

urn

The spore-bearing part of a capsule in the mosses.

usitatissimus

Means "of common use" in Latin.

utilis

Means "useful" in Latin.

utriculatus

Means "bladdery" in Latin.

uviformis

Means "having swarming bees" in Latin.

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