One of the new species named Tetramicra riparia is very delicate, with tiny white flowers smaller than a dime, website OurAmazingPlanet reported.
It was discovered along stony streams in the mountains of Baracoa, one of the rainiest and least explored areas in Cuba, Angel Vale, a researcher at the University of Vigo in Spain, said.
The plant has an unusually broad, sturdy base: its pedicel is almost four times as large as its column, Vale and his co-authors said.
The second new orchid, from the western tip of the island, dwarfs its neighbour in size. The flower's showy purple and green petals are similar to a daffodil in appearance, spreading more than 2.5 inches (7 centimetres), with up to 20 blooms on one plant.
Like many orchids, the flower, dubbed Encyclia navarroi, is epiphytic, meaning it grows on other plants for support, but not for nutrients.
Along the western coast, the species preferred to perch on plumeria and ficus, the researchers discovered.
Both new species are deceit pollinators, Vale said, enticing bees to spread their pollen without a reward.
"Contrary to most plants, many orchids do not produce nectar or other substances to compensate insects and birds that visit them," he said.
Vale and his colleagues are studying orchids throughout the Greater Antilles (Cuba, Jamaica, Hispaniola, Puerto Rico) to reconstruct their evolutionary history and analyse the effect of pollinators in their development.
One of the mysteries they aim to solve is whether deceit orchids have greater diversity than other nectar-producing species.
"Despite the fact that T riparia's flowers have a complete central petal, just like other species that make up a subgenre endemic to Cuba; the way they grow is very similar to a more widespread group that seems to have diverged on the neighbouring island of Hispaniola," Vale said.
"Our work provides molecular evidence of the greater relationship of T riparia with these species on the neighbouring island," Vale added.
The study was published in the journal Systematic Botany and the journal Annales Botanici Fennici.
