Glossary of Gardening Terms

Index A

Abscisic acid:
  A growth inhibiting plant hormone involved in dormancy, stomatal closure, leaf abscission and other stress phenomena.
Accent Plant:
  Plant used in a formal bed or border display used to emphasise hieght, colour an/or texture.
Acicular:
  Needle-like.
Acid:
  With a pH value below 7
Achene:
  A simple dry one-seeded fruit with a leathery pericarp. (E.g., sunflower "seed")
Accuminate:
  With a long tapering point.
Acre
  A measure of land totaling 43,560 square feet. A square acre is 208.75 feet on each side.
Acute:
  Ending in a short, sharp point.
Adpressed:
  Pressed flat to the axis to which it is attached.
Adventitious:
  Refers to a plant orgen that occurs in an unuasual location.
Adventitious root:
  Any root arising from a plant part other than an existing root that arise spontaneously.
Aeration:
  Lossening of the soil structure to permit air circulation.
Aerial root:
  An aboveground root.
Air Layering:
  Method of propagaton where aerial stem is covered in moist moss and sealed in plastic to form new roots.
Alkaline:
  With a pH value above 7.
Alpine:
  High altitude plant from above snowline.- Any plant suitable for rock garden.
Alpine house:
  Unheated, well ventilated greenhouse for growing alpines.
Alternate:
  An arrangement of leaves or buds in which a single leaf or bud is attached at each node.
Amentum:
  A spike of unisexual flowers; a catkin.
Amplexicaul:
  Clasping or embracing the stem.
Anaerobic:
  Not requiring oxygen to function
Androecium:
  The collective term for the male parts of the flower.
Angiosperm:
  Flowering plants bearing seeds within enclosed structures usually derived from a ripened ovary.
Annual:
  A plant that germinates, flowers, produces seeds and dies within one year or season.
Annulus:
 

Corona or rim of the corolla in the plants of the Asclepiadaceae family.

In ferns, the part of the sporangium involved in spore dispersal.
Anther:
  The part of the stamen on which pollen is produced.
Anthesis:
  The developmental stage in flowering at which the anther ruptures and pollen is shed.
Antispasmodic:
  With properties to alleviate spasms or fits.
Antitussive:
  Cough relief.
Apex:
  Terminal part of leaf, stem, root etc.
Apical meristem:
  A mass of undifferentiated cells capable of division at the tip of a root or shoot. These cells increase by division allowing the plant to grow in depth or height.
Apical dominance:
  The inhibition of growth in axillary buds by auxins produced in the growing shoot apex.
Apomixis:
  Asexual production of ripe seed. Offsprings are clones, genetically itentical to parent.
Aquatic plant:
  Plant that lives in water; freefloating,submerged, or rooted in the water with the foliage above water.
Arboretum
  A garden with a large collection of trees and shrubs cultivated for scientific or educational purposes
Areole:
  Organ peculiar to cacti, bearing spines and produced in leaf axils.
Aril:
  Accessory seed covering.
Aroid:
  Member of the Araceae family.
Aromatic:
  Fragrant.
Asexual Reproduction:
  Process of producing new individuals by apomixis or vegetative propagation.
Astringent:
  Substance that checks secretion; (i.e.. Binds) a styptic.
Auricle:
  Ear-like lobe, often in pairs at the base of an organ.
Auxins:
  A group of growth promoting hormones involved in cell elongation, apical dominance and a variety of other plant responses.
Awn:
  Stiff bristle-like projection often found on grass seeds and spikelets.
Axil:
  The upper angle formed by the junction of a leaf with the stem.
Axillary :
  A bud found arising in the angle or axis of a true leaf, indicating the position of a node on the stem.
Axis:
  Eachis, stalk, or stem on which organs such as flowers, leaves or leaflets are arranged.

Last updated 10 March, 2002
© copyright 1999, P. A. Owen