Orchid stems are also specialized into what are called pseudobulbs. These are basically expanded stems that allow the plant to store excess water and food. The roots of epiphytic (tree-dwelling) orchids have a special outer layer of dead cells called velamen. Because orchids metabolize slowly in order to not outpace their resources, the roots also absorb slowly, meaning that they need help catching water as it passes by. The velamen cells catch and fill with water as it passes by so that the true root (the core of the root structure) has ample time to access as much water as it can. Velamen is silver-white in color, but becomes transparent when wet, so that when the root is wet it turns green as you are able to see through to the inner structures of the root that contain chlorophyll.
Special thanks to David Banks of Australia, Christian Kirsch; Dr. Rudolph Jenny, Peter O'Byrne***, Eric Hagsater***, Lisa Thoerle***, Mario Blanco***, Mark Whitten***, Adam Karremans, Hakan Halander****; Daniel Jimenez***, André Schuiteman***, Dr. E.F. de Vogel, Jaap Vermeulen, Rick Barry, Dr. Guido Braeme, Rogier Van Vugt; Rene Dishong, Tom Ballinger, Mac & Helen Rivenback; Dr Rubin Salueda; Rafael Govaerts***, Padre Pedro Ortiz, Dr Leslie Garay, Vena Read, Charles Lamb, Donald Tan of Malaysia, Joseph Dougherty, Dalton Holland Baptista, Rick Cirino; Prem Subrahmanyam, ROMAN MARUSKA Czech Republic, Michael Coronado, Alejandro Taborda, Greg Butler and Oak Hill Gardens, Bill Bergstrom and Bergstrom Orchids, Donna Nash, Oliver Lenhard, D. E Vermeullen, Americo Docha Neto, Richard Korber, Carl Withner, Mark Nir, Ekkehard Schwadtke; Dr Eric Christenson, Dave Alford, Igor Zhuravlev, Tony Watkinson, David Hunt, Jean Marie Vanderwinden, Glen Ladnier, Jeffrey W. Tucker, Jorge Alejandro Paulete Scaglia, Scott McGregor, Wilella Stimmell, Eric Thiessen, Geert Volckaert, George and Kathy Norris***, David Alford, Eric Hunt, Peter O'Byrne, Allen Black, Helen Milner, Al Pickrel, Greg Riemer, Marcia Whitmore, Phillipe Musschoot, Wilford Neptune, Jean-Claude George, Tony Walsh, Greg and Kerri Steenbeeke and their Orkology Kreations Website, Jim Hamilton, Robert Fuchs and RF Orchids, Gene Monier and JEM Orchids, Jerry Bolce, Andy's Orchids, Stephen Jones, First Ray Orchids, Robert Weyman Bussey, JEM Orchids, Carlos Hajek and his Peruvian Orchid Page, Bill Morden, David Morris, Noble Bashor, Patricia Harding, Nina Rach, David Haelterman; Craig Cooper, Rocky Giovinazzo, David Friedman, Bill Pinnix, Troy C. Meyers, Linda's Orchid Page, Pierre-Alain Darlet*, Guy Cantor, Tropical Orchid Farm in Maui, H&R Nursuries, Lois Greer, Ichiro "Haru" Ohsaka and his Bulbophyllum Page, Mauro Rosim from Brazil, A World Of Orchids, Bruce Norris of Canada, Nick Doe, Neville De La Rue, Nelson Barbosa Machado Neto, Jeff Aguillon, Dale and Deni Borders, Eka Mulja Tjipta, Rick Barry, Manfred Schmucker, Uri Baruk, Mike and Candy Joehrendt, Dan and Marla Nikirk, Walter Orchard, Christer Carlson; Guillerrmo Angulo, M. Max, Paula Vagner, Tennis Maynard, Greg Allikas, Malcolm Thomas, David Morris, Jacques Deschenes, Lourens Grobler; Gary Yong Gee; José Castaño Hernández; Judd and David Janvrin* for their photo and text contributions.
This type of orchid has over 200 species and has a star-shaped appearance. Most of them have small- to medium-sized blooms and come in colors such as yellow, white, or light green, although most of them are white. The flower has a wonderful fragrance, needs even amounts of water, and prefers temperatures between 60 and 80 degrees Fahrenheit, mainly because they are not a bulb plant and therefore cannot store water. They also look beautiful in hanging baskets and pots.
Check your water. For a long time, serious growers insisted that orchids could only be watered with rainwater. Nowadays, most people just use tap water, and this is fine. However, be aware that treated water may have higher salt content, and some water is high in calcium. If you see deposits forming on your plants, you should seek out a new water source.
The most common type of orchid is probably the moth orchid, or the Phalaenopsis orchids. These are the plants that you can buy from a standard grocery store. Or if you happen to live close by an Asian supermarket, you will find truck-loads of the white or purplish-pink variety. Some fashion/interior designers even dubbed this purplish-pink color as “orchid.” (This is ultra confusing for an orchid grower, as orchids come in a million different shades and colors, but well, these are the same people who invented colors like sour lemon and spiced mustard. It’s just all marketing!)
Most orchids are not heavy feeders. Many orchids bloom year after year with no fertilizer at all. During active growth, when new leaves are being produced, you may fertilize every other time you water at half the strength recommended on the fertilizer package. However, it's important to deliver water without fertilizer at least once a month to flush excess fertilizer salts from the bark mix and avoid fertilizer burn to the roots.
Dendrobium is a massive genus containing more than (conservatively) 900 species. These range from cool-growing miniatures to huge specimen plants growing in hot conditions year round. The most commonly found types of Dendrobium are the phalaenopsis type (commonly known as den-phals, and named for the species most used in their breeding, which used to be known as Dendrobium phalaenopsis, but which is now known as Dendrobium bigibbum), and the nobile type (named for the species most used in their breeding, which is known as Dendrobium nobile).
Catasetum orchids, along with the other members of the Catasetum alliance, have big, thick pseudobulbs with an attractive fan of thin leaves along their length. The flowers can be very showy, but are unisexual, so that male and female flowers look different. Lighting affects which kind appears. They need a dry rest after flowering when the leaves drop.
Orchids of all types have also often been sought by collectors of both species and hybrids. Many hundreds of societies and clubs worldwide have been established. These can be small, local clubs, or larger, national organisations such as the American Orchid Society. Both serve to encourage cultivation and collection of orchids, but some go further by concentrating on conservation or research.