Mar 17 2020
Dancing Lady Orchid is the collective common name for the orchid genus Oncidium and its relatives. The name refers to the colorful flowers that appear like dancers in billowing dresses.
In additon to being beautiful, Oncidium and its relatives are also extremely interesting and have a long and complictaed taxonomic history. In short, Oncidium was once used as the genus name for over 650 species spread across the Caribbean, Central America, and South America. However, new research using molecular tools and a reappraisal of morphology found that 'Oncidium' was actually composed of 11 distinct genera: Comparettia, Gomesa, Miltonia, Odontoglossum, Oncidium, Otoglossum, Nohawilliamsia, Psygmorchis, Tolumnia, Trichocentrum, and Vitekorchis. An analogy would be to say that humans, gorillas, chimpanzees, and orangutans were all a single genus!
Botanists discovered that these 11 genera, some of which are not particularly closely related, all converged on a similar floral shape to attract the same types of pollinators. Additionally, these orchids were converging on the flower shape of a unrelated group of tropcial shrubs, the Malpighiaceae. Evolution was driving these orchids to look like the shrubs because the shrubs produce nectar and oils to reward visiting pollinators, whereas the orchids do not provide any reward. In effect, the orchids are mimicking the shrub flowers to trick pollinators into visiting them instead, even though the orchids offer the pollinators nothing in return. This mimicry and convergence is so striking, that it caused humans to combine them all in one orchid genus.
The next time you see a vivid Oncidium or Comparettia at NYBG's famous Orchid Show, take a moment to think about these marvels of evolution in a whole new light.