Back bulb 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 each growth, usually atop a pseudobulb.
Column The tiny, rounded, column-like extension at the base of the lip. This is the central reproductive organ of the orchid flower and contains both male (pollinia) and female (stigma) parts.
Epiphyte A plant growing upon another plant, such as on a tree.
Inflorescence The flowering part of a plant; the flower stem.
Keiki A small plantlet growing from a node on a flower stem or pseudobulb. From the Hawaiian word for child.
Lip A petal that has been modified to look different from the other petals. The lip is often the most distinctive part of an orchid flower.
Lithophyte A plant growing on or among rocks.
Medium The material that an orchid is planted in, usually not soil but an open, free-draining substance such as bark, Perlite, etc.
Mericlone A plant derived from tissue culture that is genetically identical to its parent.
Meristem The actively growing tissue emanating from the ventral growth point of a plant. Meristematic tissue is used for artificial cloning – the production of mericlones.
Monopodial Vertical growth habit where leaves emerge from a single stem growing upward. Examples: Phalaenopsis, Vanda.
Node A joint on a stem or pseudobulb from which a leaf or growth emerges.
Pollinia Little waxy bundles of pollen.
Pseudobulb A thickened portion of the stem, resembling a bulb, of many orchids. The pseudobulb functions as a water and food storage device.
Sepal The outer segments of an orchid flower, usually but not always similar to petals.
Spike A flower stalk.
Sympodial Horizontal growth habit where new growths emerge from the base of old growths. Examples: Cattleya, Paphiopedilum.
Terrestrial Growing in the ground.
Throat The inner portion of a tubular orchid lip, often differently colored.
Unifoliate Having one leaf on each growth, usually at the top of a pseudobulb.
Yellowing Term used when a leaf is turning yellow. It can be due to normal aging of the leaf, or to disease, or it can be a symptom of too much light.
Sources: New Hampshire Orchid Society (www.nhorchids.org), American Orchid Society (www.aos.org)