The second type, the nobile Dendrobium, grow warm in the summer but require a cool winter period to induce flowering. They need to experience temperatures in the 40s to low 50s (preferably) in order to flower well. They are distinguished by bearing fuzzy, flat, round, colorful flowers close to stem, which cover most of the stem on a well-flowered plant.
Like most monocots, orchids generally have simple leaves with parallel veins, although some Vanilloideae have reticulate venation. Leaves may be ovate, lanceolate, or orbiculate, and very variable in size on the individual plant. Their characteristics are often diagnostic. They are normally alternate on the stem, often folded lengthwise along the centre ("plicate"), and have no stipules. Orchid leaves often have siliceous bodies called stegmata in the vascular bundle sheaths (not present in the Orchidoideae) and are fibrous.
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.
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.