To gain more insight into the evolutionary development of orchid flowers and fruits, the orchid species Erycina pusilla was studied. The evolutionary origin of the median petaloid sepal, the callus on the labellum, and the stelidia was studied.

Embryonic stem cells have the remarkable ability to develop into any type of cell. On their way to become for example a liver or a heart cell, they must repeatedly decide between alternative developmental paths. How they make these decisions is largely unknown. An international team of biophysicists…