Varieties of Oncidium & Odontoglossum

Distinguishing Factors

• The main distinguishing factor between these two genera is the lip of the blooms, a botanical part specific to orchids that at first glance may appear to just be another petal. The lip is typically larger and sometimes different in coloration. Orchid varieties falling into the Oncidium genus have a sort of callous, or bumpy. area where the lip meets the rest of the flower, and the lip is somewhat rounded. Odontoglossum varieties lack this bumpy spot and have lips that are more sharply defined in shape.

Oncidium Orchids

• Within the Oncidium genus of orchids, there are more than 750 species. Oncidium sphacelatum, Oncidium varicosum and Oncidium crispum are just three species in this broad genus. Oncidium sphacelatum has yellow petals streaked with red to brown. In some traditional Native American cultures it has strong associations with death and the dead. Oncidium varicosum are yellow with a reddish center. They usually grow by the hundreds on long branches. Oncidium crispum have brown petals spotted with yellow. Aside from its calloused lip, Oncidium orchids might be distinguished from those in the Odontoglossum genus by distribution and growth pattern. Oncidium orchids are distributed through South and North America mainly, and while they can grow on another plant (usually a tree), there are some that grow on the ground.

Odontoglossum Orchids

• More than 400 species are found in the Odontoglossum genus. A few include Odontoglossum crispum, Odontoglossum pulchellum and Odontoglossum grande. Odontoglossum crispum is a stark white with a yellow center, as is Odontoglossum pulchellum. The two are almost impossible to distinguish. Among the most popular Odontoglossum orchids is Odontoglossum grande. This species is also called the Tiger Orchid, a name that reflects its unique coloration with tiger-like stripes of yellow and deep red. Odontoglossum orchids are usually distributed throughout South America but especially around the Andes mountains. They almost never grow on the ground. Instead, they grow from the sides of trees.

Growing Requirements for Oncidiums and Odontoglossums

• Oncidiums do well with a regular source of bright light, while Odontoglossums typically need more shade. Oncidiums should be watered about every other day, while Odontoglossums need watering only about twice a week. Both plants are sensitive to over-watering. Species in each of these genera should be fertilized every two weeks or so during the summer and not at all once the fall months arrive.