There have been a couple of botanical travel reports from Gotland with findings of white-flowered orchids, especially of Dactylorhiza incarnata. This year, I’ve finally visited this Baltic Sea island, in a quite warm and dry summer.
Such Dactylorhiza incarnata f. albiflora without any color hue have been quite rare – on my round trip by bike I’ve seen four plants. That translates into an estimated ratio of two or three per 1000 plants, which is quite the relation to be expected. Quite more often have been plants with a light yellow hue, although those could not always be addressed as the subspecies (or other taxonomic order) ochroleuca.
It was obvious that Dactylorhiza incarnata, possibly the orchid with the biggest population on Gotland, is occuring here in an marked color polymorphism – from white (very rare) to yellow (occasionally), light violet/pink (common) and the dark purple (common) flowers of the cruenta form which is sometimes viewed as a subspecies.
With Orchis mascula there have also been albiflora forms in the frequency to be expected from genetical mutations. In all those plants the pattern of purplish points in the flower lips has been preserved.
On a meadow near Oestergarn there was a beautiful white-flowered Gymnadenia conopsea among hundreds of plants..
Following a hint by Marco Klüber I also found an almost white-flowered Orchis spitzelii in a pine wood on the Northwestern coast. The color hue was still recognizable, the loss of pigments not as far reaching as here. But it’s still an indication that this orchid species also shows a genetical inclination to develop albiflora forms.
