A number of orchid-related terms are defined below.
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This section will be updated periodically with new terms. If you don't see one here, please send it to firstname.lastname@example.org and it will be added to the list.
All definitions were written by Joe Gadbois, © 2010 Orchid Society of Alberta.
· Anther cap. The structure that covers the anthers on the column of some orchids.
· Anther. The reproductive structure of a flower (part of the stamen) that holds pollen.
· Asexual reproduction. Any form of reproduction that does not involve growth from seed. Asexual reproduction always results in the offspring being genetically identical to the parent plant.
· Bifoliate (e.g. in Cattleya) Two leaves are produced per growth.
· Cane. In Dendrobium, the growth (pseudobulb and leaves) of the plant. So named because of the usual long, slender nature of Dendrobium growths.
· Chlorophyll. The pigment that makes leaves and other structures green, and facilitates solar energy absorption for photosynthesis.
· Chloroplast. The organelle within a plant cell that produces chlorophyll.
· Clone. Any individual plant created by means of asexual reproduction. Also called a cultivar. A clone can be given a special name, called a clonal or cultivar name, to distinguish it from other clones of the same species or hybrid. Clones usually originate as cultivars (created by sexual reproduction) that have superior traits, and are reproduced asexually to retain those exact traits in the offspring.
· Column. The structure containing the united sexual organs of the orchid flower, usually located above the lip.
· Cotyledon. Also called a seed leaf. It is part of the embryo and becomes the first leaf that the plant grows.
· Cultivar. Any individual plant created by means of sexual or asexual reproduction. A cultivar can be given a cultivar name to readily distinguish it from other cultivars of the same species or hybrid. Cultivars of the same species or hybrid can be distinguished from each other visually by subtle physical differences that exist due to genetic variation.
· Division. The creation of new plants by separating growths from the rhizome of the mother plant. Only possible in sympodial plants. A form of asexual reproduction.
· Embryo. The tiny, baby plant within a seed.
· Endosperm. The food reserve within a seed, which nourishes the embryo as it grows. Orchids usually have little or no endosperm in their seeds.
· Epiphyte. A plant that grows on the limbs of trees and/or shrubs.
· Family. A group of genera within the same order which collectively are different enough from other families within the order to warrant a different name. E.g. Orchidaceae (the orchid family) and Alliaceae are different families within the order Asparagales.
· Flasking. Also asymbiotic seed propagation; in-vitro. This term refers to growing orchids from seed on a sterile, nutrient-infused agar medium, to replicate the effects of a relationship with a mychorrizal fungus.
· Form (forma). An individual or very small population within a species that exhibits a trait different from all others in that species (often called a mutation). Usually this is a rare color form or unusual growth habit. In taxonomy these are given forma names; e.g. Paphiopedilum delenatii f. albinum is the albino (white flowered) form of that species, which usually has pink in the flowers.
· Genus. (Pl. “genera”) A group of species within a family which collectively are different enough from other genera within the family to warrant distinction with a different name. E.g. Cattleya and Phalaenopsis are different genera, but they are both orchids as they are within the orchid family. In Latin names (which are written in italics or underlined), the generic name is always capitalized and listed first, while the specific epithet is never capitalized and listed last.
· Hybrid. A hybrid is the result of crossing two different species, a species and a hybrid, or two hybrids together.
· In-situ. (Literally "in place") In the natural habitat.
· In-vitro. (Literally "in the glass") In the laboratory. In the context of orchids, it refers to asymbiotic seed propagation, or flasking.
· Lip or labellum. In orchid flowers, one of the petals is modified into a unique shape. This organ is called the lip, or labellum. Lips serve a variety of purposes, such as attracting pollinators to the flower, or providing a landing platform for the insect. The lip always exists to facilitate sexual reproduction in some way.
· Lithophyte. A plant that grows on rock or cliff faces.
· Macronutrients. Those nutrients that are required in large amounts for a plant to function and grow; N (nitrogen), P (phosphorus), and K (potassium) are the most important, as well as Ca (calcium), Mg (magnesium), and S (sulfur).
· Meristem. Also meristematic tissue. Sections of plant tissue containing undifferentiated cells that are able to divide rapidly. This tissue is used for micropropagation.
· Micronutrients. Those nutrients that are required in trace amounts for a plant to function and grow. Some of these are B (boron), Al (aluminum), Fe (iron), and Na (sodium).
· Micropropagation. The process by which large numbers of new plants are produced from small samples of meristematic tissue in-vitro. The tissue sample is given hormones and nutrients to induce rapid cell division, which leads to the development of the new plants. Also called cloning, because all of the offspring are genetically identical to the parent plant. This is a form of asexual reproduction.
· Monocotyledon. The term used to describe a plant with one cotyledon, or seed leaf. Orchids are monocots (the shortened form of the term). In the plant kingdom, there are also dicots (which have two seed leaves).
· Monopodial. A growth habit in which the plant has only one main growth and does not form clumps; i.e. Phalaenopsis, Vanda. The single growth grows continuously over the plant’s lifetime, slowly growing longer.
· Mychorrizae. Also mychorrizal fungus. Fungi that form symbiotic relationships with plants. They bond with the plant's roots and provide the plant with nutrients.
· Ovary. The part of the pistil that contains the ovules. After fertilization, the ovary becomes the seed pod as the ovules grow into seeds.
· Ovule. The "egg" found within the ovary of a flower. After it is fertilized, it begins to form a seed.
· Petal. In orchids, the petals form the inner whorl of the flower. There are three, one modified to form the lip. The other two are called lateral petals and are positioned on either side of the lip. They are usually brightly colored to attract pollinators. In some orchids, they are greatly reduced in size and almost invisible (as in Masdevallia).
· Photosynthesis. The process by which plants convert carbon dioxide, water, and solar energy into glucose, which is then absorbed as food.
· Pistil. The female reproductive organ of the flower.
· Pollen. The powdery or waxy, often yellow substance that contains the sperm cells of a plant.
· Pollinia. In orchids, waxy masses of pollen that are produced instead of the usual powdery pollen found in other plants.
· Protocorm. Orchid seedlings form protocorms when they first germinate. They are simply bundles of cells that have yet to form organs such as leaves and roots.
· Pseudobulb. An enlarged stem developed into a water storage organ. Exists in many epiphytes and some lithophytes.
· Rhizome. An underground stem (or, in epiphytes, a basal, horizontal stem) from which roots and growths are produced.
· Sepal. In orchids, the sepals form the outer whorl of the flower. They protect the bud as it develops. They usually are very similar to the petals, perhaps a little smaller in size, and fill in the gaps between the petals and lip. In some orchids (i.e. Masdevallia) they are enlarged and form the main visually stimulating part of the flower.
· Sexual reproduction. The creation of seeds following pollination (the act of sex in plants). Sexual reproduction always results in genetic variation within the offspring.
· Species. (sing. and pl.) A group of organisms classified into a genus which collectively are sufficiently different from others within the genus to warrant distinction with a different name. For example, Sophronitis cernua and Sophronitis coccinea are separate species within the genus Sophronitis, as denoted by their different specific epithets.
· Stamen. The male reproductive organ of a flower. Produces pollen.
· Staminode. Also staminodium. In slipper orchids, the shield-shaped structure at the front of the column, directly above the lip.
· Stigma. The surface (part of the pistil) where pollen is deposited during pollination. Usually covered in a sticky substance.
· Subspecies. A subspecies will be named within a species when there are obvious physical differences between populations that occur at large distances from each other. In orchid taxonomy, varieties tend to be more prominent than subspecies.
· Symbiotic seed propagation. The process by which seeds are germinated and grown on using the symbiotic fungi that would facilitate process in nature. In cultivation, this usually means scattering the seeds around the base of a mother plant. This has a much lower success rate than asymbiotic technique, but it was all that was available to hybridizers for many years, before such techniques were invented.
· Sympodial. A growth habit in which the plant develops many growths successively along a rhizome (forms clumps); i.e. Dendrobium, Cattleya, Paphiopedilum. Individual growths exist over a limited period of time before they are shed, to be replaced by new growths.
· Terrestrial. A plant that grows in the ground (can be used as a noun or adjective).
· Testa. The seed coat.
· Unifoliate. (e.g. in Cattleya) One leaf is produced per growth.
· Variety. A population within a species that is sufficiently different from others within that species to warrant a varietal name, but not different enough to warrant a separate species distinction. E.g. Cypripedium parviflorum var. pubescens is a variety of Cyp. parviflorum.
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