This year I had the chance to visit the white flowering form of Cephalanthera rubra in the Hesse part of the Rhoen some days earlier than last year. But first I followed a hint and looked up a place further in the South, near Ahlersbach. Quite near a path through the forest a white Cephalanthera rubra with a slight hue of pink! The pink colour is well visible in the buds, where the remaining pigments are more concentrated than in the opened flower.

At the second place near Huenfeld, characterized by an old beech mentioned by Marco Klueber in his great book about “Orchids in the Rhoen” the albiflora plants of Cephalanthera rubra are splendidly flowering. The Swedish botanist L. Anders Nilsson showed (in an article in Nature, 1984) that Cephalanthera rubra mimics the floral coloration of Campanula in the visual system of bees in order to be pollinated by them, especially by male bees of the genus Chelostoma. Since Cephalanthera rubra is flowering before Campanula, they are quite attractive for the bees. It would be interesting to see how bees are reacting to the albiflora forms of Cephalanthera rubra.

With regard to pollinators my visit on June 24th had a special highlight when I saw a wasp (Argogorytes mystaceus) pollinating Ophrys insectifera. The insect pseudocopulated two flowers in a timeframe of more than seven minutes.

With its deeply pink to purple colours in the sepals and petals and a deeply brown labellum, Ophrys bertolonii is one of the most intensely coloured Ophrys species. In Croatia, at the southern tip of Istria, Pavel Heger found a colour variety of Ophrys bertolonii – with an overall green appearance due to the remaining chlorophyll pigments. There are two characteristics which allow to address these plants as an “albiflora” form: 1) The typical marking at the lower end of the labellum is quite white. 2) The hairs at the edges of the labellum are white as well.

This rare plant demonstrates that “albiflora” forms of Ophrys species tend to retain chlorophyll – in contrast to the white flowering forms of Orchis or Anacamptis species. And there are distinct areas of the flower where chlorophyll is not retained as it is the case with the labellum marking of Ophrys bertolonii. Maybe these plants tend to be “white” in order to achieve a certain biological “albiflora” function – but the chlorophyll performance of the flower is still important and thus kept. Special thanks to Pavel for contributing to albiflora.eu!