Most white flowering orchids have a last hint of colour in its petals, its spur or ovary. In these cases, the ability to produce pigments is clearly reduced, but obviously not totally suppressed. Studying albiflora species of Gymnadenia odoratissima in the Dolomite Alps, some plants show a rest of rose colour (left) while others still have a violet hue (right) – especially visible in the buds and in the ovary. At the slope of a meadows near the Schlern mountain there are about ten plants of Gymnadenia odoratissima with more or less white flowers.

It seems that there are different pigmets suppressed in both cases. Only plants with all colour pigments suppressed have totally white flowers. That is also clearly visible with Gymnadenia conopsea at the Puflatsch alm of the Dolomite alps.

The Puflatsch Alm above the alpine village Siusi is famous for its colour varietes of Nigritella nigra ssp. rhellicani. As part of a field trip in the Dolomite Alps I had the chance to explore this region with an altitude of 1990 to 2150 metres for four days. Especially rich is the flora in the surroundings of the Arnica Huette, where thousands of Nigritella and Gymnadenia conopsea are flowering in mid July. Additional orchid species are Pseudorchis albida and – in depressed areas – Dactylorhiza majalis.

Among the flowering Nigritella colour varietes are quite common, even though I couldn’t find a totally white one. All the pale-yellow or white flowering plants still had single flowers with a slight rose hue on the edges of the lip. The most common colour variety is an inflorescence with light red flowers in the upper and pale flowers in the lower part.

Not rare at all are hybrids of Nigritella nigra ssp. rhellicani with Gymnadenia conopsea. Their carmine flowers are glowing in the meadows. Interesting was a hybrid of a colour variety of Nigritella nigra ssp. rhellicani with Gymnadenia conopsea, resulting in an inflorescence (left) much lighter than with common hybrids of both species (right):