Odontoglossum

What does Odontoglossum look like?

Most of these orchids grow on other plants, and a few grow on the ground. Each new shoot carries compact pseudobulbs, thickened stems with leaf-like bracts at their base, and one to three leaves at the top. The flower spike rises from the base and arches, sometimes standing upright. Sepals and petals are ruffled and spread wide. The lip, the flower's lower petal, is complex, held upright or alongside the long column, and is either whole or split into three lobes. Blooms can be white, red, purple, brown or yellow, and some are blotched with several colours at once. Species from high ground may carry 150 flowers on one spike.

Where does Odontoglossum come from?

The genus was named in 1816 by Karl Sigismund Kunth. Its name comes from Greek: odon for tooth and glossa for tongue, after two tooth-like calluses at the lip's base. Everything once placed here, more than 400 species, has since been moved out, and Odontoglossum is now treated as a synonym of Oncidium. Many went to Oncidium itself. Others were put in Aspasia, Cyrtochilum, Gomesa, Miltonia, Otoglossum, Rhynchostele and Rossioglossum, among other genera. The plants are cool to cold growers, found on open spots in damp cloud forest at high elevation, from Central America and western South America to Guyana; the northern Andes hold most of them.

When and how Odontoglossum blooms

These are orchids of cool, humid, high altitude cloud forest, growing in open, airy places rather than deep shade. They are epiphytes, meaning they hold on to trees instead of rooting in soil; a few are terrestrial, growing on the ground. Growth is sympodial: a new shoot starts from the base of the last, making its own pseudobulbs, leaves and flower spike. Altitude shapes the flowering. Plants from the highest, coldest places have long spikes with as many as 150 blooms, as Odontoglossum cirrhosum does. Lower altitude plants have shorter spikes, with up to about 20 flowers.

How Odontoglossum is used

Orchid lovers prize these plants for their showy, flamboyant flowers, and the horticultural trade gave the genus the short label Odm. Growers crossed them with related orchids to raise intergeneric hybrids. Nearly every hybrid with red colouring descends from a cross with species then placed in Cochlioda, above all Oncidium noezlianum, once named Cochlioda noezliana. A nothogenus is a name for a hybrid between two genera. With Odontoglossum and Cochlioda both merged into Oncidium, most of those old hybrid names are now obsolete.

Kinds of Odontoglossum

The former genus was large and varied. Over 400 species sat in it, and they now lie across Oncidium and several other genera: Aspasia, Cuitlauzina, Cyrtochilum, Gomesa, Miltonia, Oliveriana, Otoglossum, Rhynchostele and Rossioglossum. These moved plants came from climates outside the Andes. The flowers vary as much as the names, in white, yellow, red and purple, in brown, or blotched with a striking mix. Spike size runs from roughly 20 blooms at low altitude to 150 at the highest.

What Odontoglossum means

The sources tie no festival, emblem or rite to these orchids. Their importance is horticultural. For growers, the genus and its relatives formed a large breeding group, and many hybrids carry a form of its name, such as Odontioda or Odontocidium. Those names, called nothogenera, record crosses between genera, and most are no longer in use.

Questions people ask about Odontoglossum

Good reading and sources

• Encyclopaedia BritannicaArticle
• USDA Plants DatabaseUS Department of Agriculture, Article
• Plants of the World OnlineRoyal Botanic Gardens, Kew, Plant database
• Where it has been recordedGBIF, Plant database
• Sightings and photos by naturalistsiNaturalist, Plant database

• Odontoglossum on WikipediaEncyclopedia
• More photos on Wikimedia CommonsPhotos
• Wikidata recordOpen data