A new species description offers the chance to clarify open questions while studying the alpine Nigritella flora: In the latest edition of the Journal of European Orchids (1/2010), Wolfram Foelsche describes a broad spectrum of doubtful cases where Nigritella plants have been identified as Nigritella rubra without showing the characteristics of this plant as it was described by Richard Wettstein in 1889. With Nigritella rubra sepals and petals should have about the same width. But many plants identified as Nigritella rubra have petals which are considerably slimmer than the sepals. Additionally there are also differences regarding the form of the lip and the colour of the inflorescence: In most cases the plant now described as Nigritella bicolor shows a brighter red in the lower part of the inflorescence than in its upper part. And Nigritella bicolor has a longer spur than Nigritella rubra.

“With its striking inflorescence – above a rim with brightly shining rays the rows of rose-coloured flowers are displayed while the tips of bracts are set apart in dark-red – this new species, without doubt, is our splendid, most attractive nigritella”, Foelsche writes. According to his studies the majority of the photos used to illustrate Nigritella rubra are actually showing Nigritella bicolor which has a much larger area of distribution. Foelsche notes that the bicolour characteristics may be more or less strongly developed. It’s not possible to confound Nigritella bicolor with colour varieties of Nigritella rhellicani with its open labellum:

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):

Wolfgang Wucherpfennig berichtet in den soeben erschienenen “Berichten aus den Arbeitskreisen Heimische Orchideen” (Jahrgang 24, Heft 1/2007) über “Die Orchidee des Jahres 2007: das Schwarze Kohlröschen Nigritella nigra subsp. rhellicani, ein Kleinod der Berge” (S. 24-33). Dabei geht er auch auf die Farbanomalien ein. Er führt aus, dass die auffallend dunkelrote Farbe dieser Orchidee auf “eine außergewöhnlich hohe Konzentration von 2 Farbstoffen” erzeugt werde, einem purpurroten und einem gelben. Wenn das Pigmet für Purporrot fehle, “verändert sich die Blütenfarbe dann entsprechend über ziegelrot, orange bis zu gelb”. Fehlen die genetischen Voraussetzungen für die Entwicklung beider Farbstoffpigmente, so wäre zu ergänzen, ergeben sich Nigritella-Pflanzen mit weißen Blüten, wie sie von Jean-Pierr Brütsch in einem im Web verfügbaren Artikel als Nigritella nigra lus. alba bezeichnet wird.