Orchid Glossary

Some common orchid terms provided here as a starting help-guide for Web-site visitors. This is by no means a comprehensive listing but a basic guide to orchid terminology.

adventitious bud
Meristem originating from a single cell or group of cells not part of preexisting meristem.

adventitious propagation
The use of tissue culture to produce whole plants from adventitious buds. Can lead to high levels of somaclonal variation, unlike micropropagation.

aerial root
Any root that is produced above the growing medium.

anther
The part of the stamen containing the pollen; the end of the column.

axillary bud
Preexisting meristem within the axil of a leaf that is normally inactive in growth.

backbulb
An old pseudobulb behind the part of a sympodial orchid that is actively growing. Although there may be no leaves the presence of undamaged "eyes" is a sign that growth is possible.

bifoliate
Having two leaves on the pseudobulb.

cane
An elongated pseudobulb, often used to describe Dendrobiums.

cultivar or clone
An individual plant coming from one seed and its vegetative propagations in cultivation: a horticultural variety.

epiphyte
A plant, which naturally grows on another plant but is not a parasite. It gets no nourishment for the host plant. Many of the orchids in cultivation are epiphytic.

eye
The bud on a sympodial orchid that will eventually develop into a new lead.

foliar spray
Many minor nutrients and trace elements, when mixed with water are beneficial to growth. These agents are best absorbed through the stomata on orchid leaves.

genus (plural genera)
A smaller, natural, closely related group, which falls between Family and Species in classification than Family (Remember: Kingdom, Phylum or Division in plants. Class, Family, Genus and Species?)

hybrid
The offspring of a cross between species or hybrids.

inflorescence
The flowering portion of a plant.

intergeneric hybrid
A hybrid between members of two or more genera with compatible chromosomes.

keiki
A baby plant produced asexually by on orchid plant. Keikis are not unusual on Dendrobiums and Vandaceous orchids.

lead
An immature vegetative growth on a sympodial orchid that will develop into a flower producing structure.

lip
A modified petal of the orchid flower specialized to aid in pollination and different than the other petals.

lithophyte
An orchid that grows on rocks.

medium
The organic (baric, moss, tree fern) orinorganic (rock) matter on which an orchid is grown.

mericlone
A plant derived from tissue culture that is identical to its parent. Occasionally mutations may occur and the mericlone is a bit different from the parent.

meristem
The actively growing area of the plant from which mature tissues such as leaf, stems, flowers and roots originate.

micropropagation
The use of tissue culture to grow inactive axillary buds into whole plants with very little somaclonal variation, unlike adventitious propagation.

monopodial
An opposite growth pattern from sympodial. These orchids grow upward on a single stem producing leaves and flowers along the stem. Vandas have monopodial growth.

node
A joint on a stem or pseudobulb from which a leaf or growth originates.

panicle
An inflorescence with a main stem and branches, the flowers on the lower branches open earlier than the upper ones.

photosynthesis
The process a plant uses to produce carbohydrates and sugar from water and carbon dioxide in the air using chlorophyl-containing cells exposed to light.

polyploid
A plant with more than the normal two sets of chromosomes.

pseudobulb
A thickened portion of the stem of many orchids functioning as a water and food storage device.

raceme
An unbranched inflorescence of stalked flowers.

rhizome
A root-bearing stem of sympodial orchids that progressively sends up leafy shoots.

scape
An unbranched inflorescence with one flower.

sheath
A modified leaf that encloses an emerging inflorescence or leaf.

somaclonal variation
Genetic variants arising from tissue culture.

species
A kind of plant that is distinct from other plants.

spike
An unbranched inflorescence of unstalked flowers.

stem propagation
See micropropagation.

stolon
A branch that grows horizontally above the medium and produces roots and shoots at the nodes.

stomata
The holes and guard cells in leaves. The guard cells allow the holes to be open when humidity and carbon dioxide levels are right, so that waste water can be eliminated (transpiration) and so that gases can pass back and forth to and from the environment. The guard cells close these holes (stoma) to prevent water loss in the heat of the day or when humidity is low.

sympodial
Opposite of monopodial growth, these orchids grow horizontally across the medium and may have many stems. Cattleyas have sympodial growth.

terrestrial
Growing on the ground and supported by soil.

tetraploid
A plant with four sets of chromosomes. A normal plant is diploid with two sets of chromosomes. Most modern complex orchids hybrids are tetraploid. Compared to diploids, tetraploids generally have larger, fuller and heavier substanced flowers.

tissue culture
The technique of culturing cells on a sterile synthetic media. There are two general methods use to propagate plants -- micropropagation and adventitious propagation.

unifoliate
Unifoliate orchids have one leaf added to the pseudobulb.

velamen
The thick sponge-like covering of the roots of epiphytic orchids which helps prevent water loss and aids in absorption.

virus
A type of infectious agent, much smaller than common microorganisms, several forms of which affect certain kinds of orchids.