Epiphytic orchids, those that grow upon a support, have modified aerial roots that can sometimes be a few meters long. In the older parts of the roots, a modified spongy epidermis, called a velamen, has the function of absorbing humidity. It is made of dead cells and can have a silvery-grey, white or brown appearance. In some orchids, the velamen includes spongy and fibrous bodies near the passage cells, called tilosomes.
Sympodial: Sympodial orchids have a front (the newest growth) and a back (the oldest growth).[5] The plant produces a series of adjacent shoots, which grow to a certain size, bloom and then stop growing and are replaced. Sympodial orchids grow laterally rather than vertically, following the surface of their support. The growth continues by development of new leads, with their own leaves and roots, sprouting from or next to those of the previous year, as in Cattleya. While a new lead is developing, the rhizome may start its growth again from a so-called 'eye', an undeveloped bud, thereby branching. Sympodial orchids may have visible pseudobulbs joined by a rhizome, which creeps along the top or just beneath the soil.

This site is compiled from photos collected from growers or photo collectors around the world and I rely on them to try to be sure of their identification. As we all know, however, many plants are mislabeled and growers and collectors can't know all species in every genera, so please be advised that to the best of our knowledge the following ID's are correct. I have hundreds of references, thanks to you all, but often many species are not well represented. I try to the best of my capabilities to be correct but as the adage goes, "To err is human". Many species herewith have been scrutinized by taxonomic experts and will be correct, but this may not be true of all the species described. If you have any questions as to the veracity of any species described in this encyclopedia please e-mail me, Jay Pfahl, at jfal@sprynet.com and we will work at correcting the mistake. As to the text it is compiled by culling notes from hundreds of books and publications [See Bibliography and source books] but it too can be wrong in part due to my mistake or in the often conflicting reports on various orchids.
There are lots of orchid photos. I spent 16 days in country and managed to visit Sao Paulo state beaches, littoral plain and littoral mountains as well as the Mantiquera Mountains and up to Diamantina in northern Minas Gerais all by car with the well known Brazilian orchid expert, Marcos Campacci. The name may ring a bell as he is the describer of many new Brazilian orchid species such as Cattleya tenuis. He is also the editor of Boletim CAOB and Brasil Orqueideas, 2 major orchid publications in Brazil.
Cymbidium carry tall stems with many flowers that have a more typical orchid shape. They are easily identified by their grassy leaves, and they readily form large clumps. Most common are the cool-flowering types, which need to experience a cooler winter (nights in the 40s for some time in the fall) in order to initiate flowering. Once the flowers open, they can last for up to two months or more, especially in a cool environment. These are very showy and rewarding plants, and a plant in a six-inch pot can carry three stems with 15 or more flowers each, depending on the type. 

The Gongora orchid genus is a really neat type of orchids, related to Stanhopea. They have nice, strong fragrances, often of cinnamon, allspice, or nutmeg. The flower stems hang over the pot's edge and the flowers point downwards. They can adapt to a wide variety of lighting conditions and a relatively large temperature range, but like a lot of water.
^ Thomas J. Givnish, Daniel Spalink, Mercedes Ames, Stephanie P. Lyon, Steven J. Hunter, Alejandro Zuluaga, William J.D. Iles, Mark A. Clements, Mary T.K. Arroyo, James Leebens-Mack, Lorena Endara, Ricardo Kriebel, Kurt M. Neubig, W. Mark Whitten, Norris H. Williams, and Kenneth M. Cameron. 2015. "Orchid phylogenomics and multiple drivers of their extraordinary diversification". Proceedings of the Royal Society, series B (biological sciences) 282(1814):pages??. doi:10.1098/rspb.2015.1553.[full citation needed]
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.