This genus contains many species from the American continent. These plants need only a little care and can be grown under several circumstances. Some species in these genus originate from the coastal areas, whereas others come from the snow covered mountain peaks. Therefor there is a large choise in Oncidium species. The main problem in this genus is that due to the many species and the great variety, it is difficult to settle the discussions about how this genus should be structured in botanical terms. The main groups in this genus Oncidium are Cyrtochilum, Slenidiopsis, Mesospinidium, Ada, Baptistonia, Tolumnia, Braasiella, Olgasis, Sigmatostalix, Aspasia, Comparetia, Cischweinfia, Helcia, Notylia, Trichopilia, Ionopsis, Leochilus, Psygmorchis, Macradenia, Lockhartia. But there are many more.
When speaking about an Oncidium group that needs a real resting period, one could think of the yellow Dancing Ladies. This is a plant with long branches covered with yellow flowers and should be kept dry in winter. It should then receive water only once in three weeks. Other Oncidiums like Oncidiums ornithorhynchum and Oncidiums sphacelatum should be kept moderately moist, but certainly not wet.
- Oncidiums that grow best in a humid atmosphere are the Oncidiums known as sycopsis papilio and Psygmorchis pusila. They originate from warm tropical areas.
- Every Oncidium needs a humidity between 30 and 60 %.
- Dressing should be applied twice a month.
- Temperatures range from 12 oC to 20 oC at night for the warmth loving species.