While travelling in Attica, Greece, Marco Klüber photographed this special Ophrys helenae which demonstrates the bilateral symmetry of orchid flowers. The left half of the lip shows the regular red-brown coloring while the right half is hypochrome, with a partial loss of pigments. The lighter red hues are preserved, in addition to the chlorophyll in the lower edges.
Orchid flowers have a bilateral symmetry – as it’s the case with beetles or the human face elsewhere in nature. Other plants like the flowers of liliaceae have a radial symmetry with three or more mirror lines.
On his trip Marco also saw the albiflora form of Anacamptis papilionacea subsp. messenica (formerly subsp. heroica):
Though Dactylorhiza fuchsii is developing albiflora forms more often than other European orchids, especially in certain regions (Ireland, some German regions), there are no mentions of white-flowered Dactylorhiza saccifera. Both species are diploid and related with each other. Exploring the marsh areas of the Smolikas mountain in mid-June in Northern Greece, I’ve seen this splendid Dactylorhiza saccifera f. albiflora on wet grounds, in a height of 1200 m, embedded in Marsh Horsetails (Equisetum palustre) and accompanied by Dactylorhiza baumanniana and Neottia ovata.
In the same area there was also a white-flowered Gymnadenia conopsea with a slight purple hue.
Another highlight of the field trip to Northern Greece: three white-flowered Dactylorhiza cordigera on a clearing in the Vitsi mountain range near Kastoria. Those were surrounded by more than 1,000 cordigera plants with their characteristic deep purple colour.
The picture of albiflora forms of late flowering orchids in Northern Greece was completed by a Dactylorhiza incarnata f. albiflora near the village of Chrisi:
Limodorum abortivum: Albiflora form (left; Photo: N.Griebl) and common form (right)
Limodorum abortivum is one of the rarest albiflora forms of orchids. Sometimes, literature is mentioning the existence of white flowering plants, e.g. Horst Kretzschmar states in his new “Die Orchideen Deutschlands und angrenzender Laender” (Wiebelsheim 2008), p.163: “In Southern Europe, there is a broad variation of flower colours, from white to purple to red, these colours have not been observed in Germany up to now, though.” Norbert Griebl in Austria has sent me a photo of an albiflora form he found in northern Greece. He observed that the plant has a green stem and green sheathing leaves, “which prooves that Limodorum is not totally living saprophytic” (=myco-heterotrophic).
Compared with the violet stem colour of the regular form the green colour of the stem is indead striking. The existent chlorophyll is obviously covered by dominant anthocyanins. When these purple pigments are absent – as it is the case with the albiflora form – the green chlorophyll colour becomes clearly visible. A study published in 2006 (M. Girlanda, M. A. Selosse, D. Cafasso, F. Brilli, S. Delfine, R. Fabbian, S. Ghignone, P. Pinelli, R. Segreto, F. Loreto, S. Cozzolino and S. Perotto: Inefficient photosynthesis in the Mediterranean orchid Limodorum abortivum is mirrored by specific association to ectomycorrhizal Russulaceae. In: Molecular Ecology 15, 2006, S. 491-504) recognizes the existence of chlorophyll but stated that Limodorum abortivum’s photosynthesis “was found to be insufficient to compensate for respiration in adult plants”. It would be interesting to know how the albiflora orchid is behaving in this regard and if it is also dependent on nutrition by fungi.
