 | Cal Pacific Orchid Farm ENGLISH Selection of orchids (including species), designer orchid arrangements, mounted plants, and orchid boarding services offered. Established in 1976. Encinitas, California, USA.  | | |
| Cal-Orchid ENGLISH Selection of orchids offered. Culture notes. Santa Barbara, California, USA. | | |
| California Orchids ENGLISH Orchid boarding facilities in the San Francisco Bay area. Bi-annual orchid sale. Greenhouse design consulting. Mary Nisbet. Bolinas, California, USA. | | |
 | California Sierra Nevada Judging Center ENGLISH Serving the Central Valley of California and Northern Nevada. Judging schedule, documents, and awards index including photos and descriptions. Sacramento, California, USA. | | |
 | Calypso Orchid ENGLISH Blog by "calypsogrower" covering many topics about the orchid genus Calypso. California, USA. | | |
| Calypso Orchid Company ENGLISH Site dedicated to Calypso bulbosa. Seed is offered for sale. Philo, California, USA. | | |
| CalypsoLip JAPANESE / ENGLISH Photos of wild orchids (and birds) found in Japan. | | |
| Cameleon Orchidee DUTCH / GERMAN / FRENCH / ENGLISH / SWEDISH Three nurseries (De Vreede, Fransen, Geest) producing a selection of orchids for sale in Europe. Based in the Netherlands. | | |
| Camp Lot A Noise Tropicals ENGLISH Specializing in orchid species and supplies. Culture notes. Photos. Karen and Jerry Sellers. Sarasota, Florida, USA. | | |
| Camp One Orchids ENGLISH Specializing in Disas with a selection of other genera offered. USA distributor for Supersphag (sphagnum moss from New Zealand). Waldport, Oregon, USA. | | |
| Canadian Orchid Congress ENGLISH / FRENCH The COC is an association of orchid societies in Canada promoting the cultivation of orchids through hybridizing, exhibition, publications, conservation, lectures, and seminars. | | |
| Canaima Orchids ENGLISH Specializing in clones of Cattleya and Laelia species. Image gallery of Cattleya habitats in Venezuela. Ellenton, Florida, USA. | | |
| Cape Fear Orchid Society ENGLISH Membership and activity information. Growing tips and show table results. North Carolina, USA. | | |
| Cape Orchids ENGLISH Regional monograph on the indigenous orchids of the Cape Floristic Region, South Africa. | | |
| Capital City Orchid Society ENGLISH Contact and meeting information for this friendly society located in New Zealand's capital city. Phil Tomlinson. Wellington, New Zealand. | | |
| Caring for Orchids ENGLISH CD and e-book available with orchid care information by Wiley F. Barker. | | |
| Carmela Orchids ENGLISH Cattleyas, Phalaenopsis, Oncidiums, and Dendrobiums offered. Flasks available. Culture notes. Hakalau, Hawaii, USA. | | |
| Carolina Orchids ENGLISH Bulbophyllums, Paphiopedilums, Phragmipediums, Angraecoids, and other species available. Tom and Shan Nasser. Fort Mill, South Carolina, USA. | | |
| Carsten's Orchid-Depot ENGLISH Orchid notes with some supplies offered. Carsten Franke. St. Paul, Minnesota, USA. | | |
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