Tap root The primary, downward-growing root of a plant (especially a tree); also applied loosely to any strong downward-growing root.

Taxon (pl. taxa) A group of living organisms at any rank; applied to groups of plants or entities that share distinct, defined characters.

Tender Of a plant that is vulnerable to frost damage.

Tendril A modified leaf, branch, or stem, usually filiform (long and slender) and capable of attaching itself to a support. (See also Climber.)

Tepal A single segment of a perianth that cannot be distinguished either as a sepal or petal, as in Crocus or Lilium. (See also Perianth segment.)

Terminal At the tip of a stem or branch; usually refers to a bud or flower.

Terrarium An enclosed container made of glass or plastic in which plants are grown.

Terrestrial Growing in the soil; a land plant.

Thatch A layer of dead, organic matter intermingled with living stems that accumulates on the soil surface in lawns.

Thin (of soil) Used loosely of poor soil, prone to capping and drought.

Thinning The removal of seedlings, shoots, flowers or fruit buds to improve the growth and quality of the remainder.

Tilth A fine, crumbly surface layer of soil produced by cultivation.

Tip prune To cut back the growing tip of a shoot to encourage sideshoots or to remove damaged growth.

Tissue culture (of plants) The growing of plants under sterile conditions in artificial media.

Top-dressing 1) An application of soluble fertilisers, fresh soil or compost to the soil surface around a plant or to lawns to replenish nutrients. 2) A decorative dressing applied to the soil surface around a plant.

Topiary The art of clipping and training trees and shrubs into various, usually intricate, geometric or free shapes.

Topsoil The uppermost, normally fertile, layer of soil.

Trace element See Micronutrients.

Translocated (of dissolved nutrients or weedkillers) Moving within the vascular system (conducting tissues) of a plant.

Transpiration The loss of water by evaporation from the leaves and stems of plants.

Transplanting Moving a plant from one position to another.

Tree A woody perennial plant usually with a well-defined trunk or stem with a head or crown of branches above.

Trellis A latticework structure designed to support climbing plants.

Trench digging See Double digging.

Triploid Having three basic sets of chromosomes. Such plants are normally sterile (see Diploid).

True (True-breeding) Of plants that when self-pollinated give rise to offspring similar to their parents.

Trunk The thickened, woody, main stem of a tree.

Truss A compact cluster of flowers or fruits.

Tuber A swollen, usually underground organ derived from a stem or root, used for food storage.

Tufa Porous limestone rock that absorbs and retains moisture; used for cultivating alpine plants difficult to grow in garden soil.

Tunic The fibrous membranes or papery outer skin of bulbs or corms.

Tunicate Enclosed in a tunic.

Turion 1) A detached, overwintering, usually fleshy, bud produced by certain water plants. 2) A term sometimes applied to an adventitious shoot or sucker.

 

 

Thief A thief in Paris planned to steal some paintings from the Louvre.   After careful planning, he got past security, stole the paintings and made it safely to his van.   However, he was captured only two blocks away when his van ran out of gas.  When asked how he could mastermind such a crime and then make such an obvious error, he replied, 

"Monsieur that is the reason I stole the paintings.

I had no Monet

to buy Degas

to make the Van Gogh"