Glossary of Gardening Terms

Index I

Imbricate bulb:
  A bulb in which the modified leaves are scale-like and overlapping like shingles (e.g., Lily).
Imparinate:
   Unequally pinnate leaves.
Imperfect flower:
   A flower which lacks one of the types of sexual organs, so that it is either male of female.
Incised:
   Deeply, regularly, and sharply toothed or lobed.
Incomplete flower:
   A flower missing any of the four types of floral organs.
Incurved:
   Bending inwards.
Indehiscent:
  A fruit which does not open at maturity to disperse the ripe seed.
Indumentum:
   Covered with hairs or, sometimes, scales.
Indusium:
   Tissue covering a sorus on a fern frond.
Infectious disease:
   Any plant disease caused by a pathogen which can be spread from a diseased to a healthy plant.
Inferior ovary Epigynous:
   An ovary in which the floral parts appear to arise above it.
Infertile:
  

Refers to soil that is very low in nutrients.

Applied to plants that do not flower or fruit for various reasons, but may do so if the conditions are right for them.
Inflorescence:
   Flower bearing stem axis.
Infusion:
   Liquid containing soluble constituents extracted from herbs.
Inoculum:
   The portion of individual pathogens that are brought in contact with a plant.
Insecticide:
   Chemical treatment used to eradicate insect pests.
Insectivorous:
   (see carnivorous)
Insert:
   Place cuttings in a growing medium.
Intercalary meristem:
   A meristem located at the base of a grass stem which produces cells for upward growth of leaves. It is not removed when grass is mowed.
Intergeneric hybrid:
   Result of crossing plants of 2 distinct, usually closely related genera.
Internode:
   The region of a stem between two successive nodes.
Interrupted:
   Refers to a structure that is not continuous.
Interspecific Hybrid:
   Result of crossing 2 species within the same genus.
Invasive:
   Describes a vigorous plant that rapidly overwhelms more delicate neighbours unless its spread is restricted.
In vitro:
   Living or growing in a test tube, or petri plate. Latin for "in glass."
Involucre:
   ring of crowded bracts, often overlapping, around the base of a flowerhead or umbrel.

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