Loss of pigment with Himantoglossum adriaticum

photo: Matthias Svojtka, 4.6.2014, in Vienna

Himantoglossum hircinum and Himantoglossum robertianum belong to the most common orchid species in southern Europe. In case of both species there are regularly plants with flowers lacking the Anthocyanine pigment. Those albiflora forms have green and white flowers instead of flowers with reddish stripes and points.

photo: Matthias Svojtka, 4.6.2014, in Vienna

Matthias Svojtka of the University of Vienna has also found an anthocyanine free form of the much rarer Adriatic lizard orchid (Himantoglossum adriaticum). “At this Himantoglossum location in the Lower Lobau there is a quite big population of about 40 to 60 plants in open grasslands, every year there are also one or two white-flowered plants“, he wrote about his photos.

photo: Matthias Svojtka, 4.6.2014, in Vienna

always beautiful: Gymnadenia conopsea f. albiflora

A region in the Steiermark, in the Austrian Alps, is the aim of a second hike in the mountains in Corona year 2020. On the Tauplitz-Alm I am mainly interested in the diversity of Nigritella species. Among the most common orchids of this mountain region is the fragrant orchid (Gymnadenia conopsea). Hundreds of them are flowering on meadows and forest clearings. Hiking to the Lawinenstein (1965 m) on July 7th I was surprised by a white-flowered Gymnadenia conopsea, with a long inflorescence. Gymnadenia conopsea is an orchid species which is developing white-flowered mutations quite regularly. But in most cases there are only singular plants of this form.

Albiflora abundance with Anacamptis palustris

In most regions of its distribution area Anacamptis palustris (synonyms: Orchis palustris, Paludorchis palustris) is highly endangered, because fens and wet meadows are more and more reduced. In a fen in the Bavarian district of Rosenheim there are still growing thousands of this special species.

On a meadow with about 100 flowering Anacamptis palustris there are also 7 albiflora forms – that’s a much higher percentage than what you could expect just by random genetic mutations. H. Kretzschmar, W. Eccarius and H. Dietrich (Die Orchideengattungen Orchis, Anacamptis, Neotinea. 2007) note: Rarely there are white-flowered plants showing a photo of an albiflora form from Lake Neusiedle in Austria. It seems that white flowered Anacamptis palustris are really rare, similar to its sister species Anacamptis laxiflora.

All flowers of the albiflora plants have not the slightest hue of purple. Even the pollinia are bright with a slight yellow influence, similar to the buds.

Anacamptis palustris in this fen is accompanied by smaller groups of Orchis majalis, Dactylorhiza incarnata subsp. ochroleuca, budding Epipactis palustris and Liparis loeselii.

Orchis pauciflora with reduced carotenoid pigments

Orchis pauciflora – photo: Bariša Ilić 

Among a population of about one thousand Orchis pauciflora in Southern Croatia, Bariša Ilić from Metković found 8 plants with almost white flowers. Their bright lips are contrasted with its reddish spots. This is the first time that he observed those special forms at a location near the town of Ston, in Dubrovnik-Neretva county. Bariša Ilić is an ornithologist, who fell in love with native orchids five years ago, as he explains.

Orchis pauciflora – photo: Bariša Ilić 

The flowers of Orchis pauciflora have a strong yellow color. They contain high concentrations of carotenoids – pigments who create the yellow flower color with many plants. While anthocyanines – which create red, purplish or brownish flower colors – are water soluble, carotenoids are lipid soluble (like chlorophyll). Since anthocyanines are produced in a complex process of biosynthesis with the participation of more than five enzymes, it is more likely that there will be a loss of anthocyanines than it might be in the case of carotenoids. This might explain why Orchis pauciflora with whitish instead of yellow flowers are extremely rare – and even in these findings, the plants seem to have retained a last rest of yellow color in the center of the labellum.

This impression of a gradual loss of carotenoid pigments corresponds with an interesting study of the Italian botanist Alessia Luca. She showed how the concentration of carotenoids is changing in the case of hybrids between Orchis pauciflora and Orchis mascula. Her thesis at the Università della Calabria includes the measuring of anthocyanin and carotenoid concentrations in the labellum of the hybrid plants, Orchis x colemanii. The results show that concentration von carotenoids is gradually decreasing in the hybrids: “O. xcolemanii showed a continuous flower color variation (Figure. 13) ranging from red-purple flowers of O. mascula to yellow flowers of O. pauciflora.” (Alessia Luca: Evolutive significance of hybridization in Mediterranean deceptive orchids, p. 42)

Alessia Luca: Evolutive significance of hybridization in Mediterranean deceptive orchids, p. 43

Comeback for the white Orchis militaris

In 2006, I first observed a white-flowered Orchis militaris in a grassland area near Frankfurt. It re-appeared in five following years. Last time I have seen it in 2010. But then it disappeared, no sign of an albiflora form among the more than 100 Orchis militaris plants of these meadows. Until this year, when it flowered again in a distance of about five meters from the first plant.

Orchis militaris f. albiflora

After the first third of May the inflorescence was already about to fade. The orchid expert Werner Hahn told me that in the 1980s the flowering in this habitat started only at about mid May – clearly a consequence of climate change in the last more than 30 years.

But the question remains: What is the reason that the albiflora form has a comeback after ten years? Seeds of the white-flowered plant might have been spread on this meadow. The color of flowers is a factor which is inherited by dominant alleles. But there still remains the small chance that the genetic characteristics of white flower will be expressed by the new plant in a population of more than 100 plants of the standard color.

Orchis militaris f. albiflora

The probability of albiflora forms among populations of Orchis militaris is about 1/1000, I guess. In the Middle Rhine Valley this beautiful plant is just flowering:

Orchis militaris f. albiflora – photo: Werner Hahn

Colony of Orchis quadripunctata f. albiflora

Orchis quadripunctata – photo: Robert Crnković

Orchis quadripunctata is a more than common species in mid Dalmatia. For more than ten years, Robert Crnković is looking for white, albiflora examples among numerous local populations  in the region of Trogir. In the beginning of May, he writes, I literately “stepped on” a small group of about 50 normal, pinkish plants, and, within the group, 14 snowy white ones. Such a great colony of albiflora forms can’t be explained by spontaneous mutations of individual plants. It seems that the white-flowered forms have propagated themselves in a quite unusual way.

Orchis quadripunctata – photo: Robert Crnković

In some cases of white-flowered Orchis albiflora the two or four small points on the base of the labellum – to which the name of the plant refers – retain the standard purplish color. Here the flowers are quite white.

Orchis quadripunctata f. albiflora – photo: Robert Crnković

Robert noted that all of these 14 plants have unspotted leaves – while the plants with purplish flowers have spotted leaves. This observation is conforming to the leaves of albiflora forms of other species like Dactylorhiza fuchsii which also lack the spots. The lack of Anthocyanine pigments affects not only the flowers but also the leaves.

Orchis quadripunctata f. albiflora – photo: Robert Crnković
Orchis quadripunctata f. albiflora – photo: Robert Crnković

Albiflora spring in Dalmatia

Himantoglossum robertianum – photo: Robert Crnković

Time and again, you can see the strong inflorescences of Himantoglossum robertianum in its hypochrome form. Jadranka Gubaš has now detected five of those plants at the coast near Šibenik, on a meadow with about 100 plants overall. Robert Crnković has taken the photos – thanks to both for this special greeting at the beginning of a new flowering season.

Himantoglossum robertianum
photo: Robert Crnković
Himantoglossum robertianum
photo: Robert Crnković

Albiflora forms on Alpine meadows

A highlight of the field trip to the Alpine region of Eastern Tyrol is a plant which on first sight appears as a stronger Pseudorchis albida. There are many of this species on the mountain meadows of the Golzentipp summit (2317 m) north of Obertilliach in the valley of Gail. Even more numerous is only Gymnadenia conopsea. But quite rare is the hybrid between both species. Studying the single flower it can be seen that this plant is such a Gymnadenia conopsea x Pseudorchis albida which has also been described as xPseudadenia schweinfurthii.

Size, lip form and length of spur are in the middle between Pseudorchis and Gymnadenia. But the color of the flower shows almost no influence of Gymnadenia conopsea flowering in purple violet. Only in the sepals there is a very faint hue of violet. Other findings of this hybrid, among them also some of the Golzentipp slopes, show flowers with a distinctive bright rose color. Thus, it may be assumed that this plant is a hybrid between an albiflora form of Gymnadenia conopsea and Pseudorchis. But it could also be possible that there is a mutation of a hybrid resulting in a lack of pigment development in the flowers.

Albiflora forms of Gymnadenia conopsea are quite common – on the Golzentipp meadows as well as above the Kircher Almen near Untertilliach at a similar height.

Dactylorhiza pythagorae f. albiflora

Foto: Kiros Kokkas

This orchid is only known from the Aeagean island of Samos. It is not variable, but in contrary unusually homogeneous, writes Wolfgang Eccarius in his book Die Orchideengattung Dactylorhiza (Eisenach 2016). But Kiros Kokkas found a white-flowered form of this rare orchid, which is usually flowering in pinkish to rose or mauve colors. This plant is obviously unique – but it also demonstrates that all the species of Dactylorizha tend to develop albiflora forms.

Foto: Kiros Kokkas

Lady’s Slipper without Chrysanthemin

Cypripedium calceolus

It’s very rarely that the Lady’s Slipper orchid (Cypripedium calceolus) is flowering without the brown-red color in sepals and petals. As with other orchid species this color is created by a pigment from the group of anthocyanines, called chrysanthemin. If this pigment is not produced, there are only carotinoids and chlorophyll left als coloring pigments. The results are yellow to greenish flowering plants. In contrast to Orchis or Dactylorhiza – but similar to Ophrys – the flowers of Cypripedium calceolus also contain chlorophyllum, thus participating in the photosynthesis.

No species of this genus has so many taxonomic descriptions of varieties as C. calceolus, writes Wolfgang Eccarius in his book Die Orchideengattung Cypripedium (Buergel 2009). In Thuringia, plants with pure yellow petals and sepals has been described as var. citrina by the teacher and botanist Bernhard Hergt (1858-1920), in Mittheilungen des Thueringischen Botanischen Vereins 1899, S.120f., indicated as f. citrinum by Eccarius.

A forma viridiflorum with greenish perigon (sepals and petals) has been described in the same journal in 1897 by Max Schulze (1841 – 1915). The author of the oldest of these descriptions is Alphonse Rion (1809-1856), who named a flava, a forma flavum, in his Guide du Botaniste en Valais, published in 1872.

Cypripedium calceolus

Those plants without Chrysanthemin also miss the common crimson dots on the staminodium at the entrance of the labellum.

Cypripedium calceolus