In a paper published in the latest edition of the Journal Europaeischer Orchideen (vol 44, 2/2012, p. 421-426), Wolfgang Wucherpfennig reviews the recent publications about the phylogenetic tree of the Monocotyledonae. He points out that the Orchidaeceae are between 104 and 120 million years old (A in the phylogenetic tree) and that the first orchids have been grazed by dinosaurs. So, orchids are in fact older than their relatives in the Amaryllis family (Amaryllidaceae) or the Asparagus family (Asparagaceae). Only the differentiation of the genera of orchids (B in the phylogenetic tree) has a more recent age and happened between 76 and 84 million years ago. Wucherpfennig concludes: “So, orchids are not a young plant family at all, they have a dignified age. But very old families also have small children which are enterprising and adventurous such as Ophrys and Dactylorhiza.”
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Thanks to all the contributions to this project website albiflora.eu I’ve compiled a first paper about the white-coloured forms of orchids, published in Berichte aus den Arbeitskreisen Heimische Orchideen (1/2012, p. 141-170). Following a short overview about taxonomic aspects the relationship of flower colour and fertilizers are discussed. The main part considers the differences of albiflora forms with particular genera of orchids. The paper finishes with a discussion of high frequencies of albiflora forms with Dactylorhiza fuchsii in Western Ireland and certain regions in Germany. Where does random mutation ends and where begins an evolutionary process? One possible scenario might be that nectar deceptive orchids flowering earlier than Dactylorhiza fuchsii – as there are Orchis mascula or Dactylorhiza majalis – impart fertilizing insects the experience that flowers with a certain form and a purple colour don’t grant them any nectar. Thus, a colour change to white might be an advantage. The German language paper can be downloaded here.
Orchid locations are constantly changing: On a meadow last visited in 2010, the number of Dactylorhiza fuchsii has been quite smaller this year. Now, there have been more Dactylorhiza majalis then before – and several hybrids of both species. These may have quite different forms: either short plants with the broad leaves of majalis (above) and brighter, fuchsii-like flowers with a broad labellum – or more elongated, with narrow leaves and purple flowers with a slightly broader labellum (down).
The Dactylorhiza fuchsii on this meadow which has both wet and dry areas are still quite bright, but most retain some purplish hue, at least in the pattern of the labellum. This time, an albiflora form of Dactylorhiza majalis was also flowering.
Misumena vatia, a crab spider has developed a special relationship with orchids. Sitting on an albiflora form of Dactylorhiza fuchsii it wears its white body, as Norbert Griebl has observed. Now I’ve watched her in Thuringia on Cypripedium calceolus in its yellow form – a perfect mimicry. The spider makes use of the fact that the slipper-shaped pouch of the plant traps small insects in order to ensure its fertilization – while is spider is only interested in food.
The spider changes its colour by secreting a yellow pigment into the outer cell layer of its body.While sitting on white flowers, this pigment is transported into lower layers. The colour change from white to yellow takes between 10 and 25 days, the reverse about six days.
The Cypripedium calceolus in Thuringia show almost none varieties in terms of flower colours. Among more than 1000 plants I’ve found one with reduced anthocyanin pigments in sepals and petals which could be addressed as Cypripedium calceolus forma citrinum.
In July, the dark red heads of Nigritella rhellicani (syn: Nigritella nigra ssp. rhellicani) are covering many alpine meadows. In some rare places, the flowers show remarkable colour variatation. After studying the Nigritella hues of the Dolomite Alps, this year I visited the Swiss canton Valais: Near Chandolin there is a place in an altitude of about 2400 m with pink and yellow flowering Nigritella rhellicani. The tableau above shows the colour varieties in both the Dolomites and Switzerland. The yellow flowering forms grow near Chandolin – they obviously miss the anthocyanins, but have other pigments as probably carotenoids. The reasons for this special forms are unknown up to now.
In the latest issue of “Berichte aus den Arbeitskreisen Heimische Orchideen” (27/2, 2010), Klaus Boie presents a rare hypochrome form of Ophrys speculum in his article about orchid-findings in western Andalusia (p.117-122). He found this forma flavescens in the Spain region of Andalusia, in the midst of a large group of Ophrys speculum, as he writes.
The marking of the labellum is just white, the other parts of the flower are yellowish-green. As with other hypochrome forms of Ophrys, the photo shows a total lack of anthocyanins. But the flower has still chlorophyll embedded – in contrast to albiflora forms of other orchid genera with their their pure white flowers. Probably the Ophrys species need the flower’s contribution to photosynthesis, because the leaves of the rosette are withering at an early stage.
Similar to The Burren there are also some continental locations where Dactylorhiza fuchsii tends to develop white or at least bright flowers. In the Belgian province of Liège, near Lanaye, there are dozens of albiflora forms of this species, as Jeroen Gerdes told me – he sent me the photo at the left.
Today I visited a meadow near Biebergemuend in the Hesse part of the mountain range called Spessart. On a space of about 5,000 square meters I counted about 300 Dactylorhiza fuchsii with the following distribution of flower colours (in per cent):
|Dactylorhiza fuchsii with||%|
|dark pink flowers||2|
|medium pink flowers||6|
|bright pink flowers||45|
|white flowers and labellum marking||44|
|white flowers without marking||3|
In total 10 of about 300 Dactylorhiza fuchsii are albiflora forms – such a frequency is quite higher than usually observed with this or other orchids species and leads to the assumption that there might be some gradual or saltational evolution under way.
Among the other plants in this area I noted Dactylorhiza majalis (withered), Dactylorhiza fuchsii x majalis, Platanthera bifolia, Neottia ovata, Rhinanthus minor, Cirsium arvense, Campanula persicifolia, Picris hieracioides and Arnica montana. Dactylorhiza majalis grows in the neighbourhood of wet ditches along the meadow – and there are also hybrids of D. majalis and D. fuchsii – still flowering while D. majalis is already withered. The hybrids are rather strong, some of them with a height of up to 50 cm. They can easily be determined by their broad leaves and the rounded labellum of the flowers with a reduced medium lobe. There is also an albiflora form of Dactylorhiza fuchsii x majalis (right).
Studying a marsh with about 2,000 Broad-Leaved Marsh Orchids (Dactylorhiza majalis) at the Southern edge of the Rhoen region in Germany I saw a group of three albiflora plants together with Menyanthes trifoliata, Caltha palustris and other marsh plants. Even more interesting was another albiflora plant in a distance of about 40 meters with an orchid in its direct neighbourhood showing a kind of partial albiflora: Most of its flowers have the standard purple colour but some flowers are partly purple, partly white – either in the lip or in the petals.
Obviously, the genetic allele containing information for the albiflora form has plaid a certain role for this plant – but it was dominated by the DNA, which contains the information for the standard colour. This observation as well as a similar one in Southern France with Anacamptis morio poses questions about the recessive character of the albiflora allele. There might be some cases where the albiflora allele of one parent plant is not totally restrained by the dominant purple allele of the other parent plant which results in such purple and white spotted flowers. Before I continued the trip to a charming meadow with hundreds of Anacamptis morio (among them two albiflora) and Orchis mascula I made use of the rising morning sun to make some more photos of the Dactylorhiza majalis f. albiflora trio:
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:
With its deeply pink to purple colours in the sepals and petals and a deeply brown labellum, Ophrys bertolonii is one of the most intensely coloured Ophrys species. In Croatia, at the southern tip of Istria, Pavel Heger found a colour variety of Ophrys bertolonii – with an overall green appearance due to the remaining chlorophyll pigments. There are two characteristics which allow to address these plants as an “albiflora” form: 1) The typical marking at the lower end of the labellum is quite white. 2) The hairs at the edges of the labellum are white as well.
This rare plant demonstrates that “albiflora” forms of Ophrys species tend to retain chlorophyll – in contrast to the white flowering forms of Orchis or Anacamptis species. And there are distinct areas of the flower where chlorophyll is not retained as it is the case with the labellum marking of Ophrys bertolonii. Maybe these plants tend to be “white” in order to achieve a certain biological “albiflora” function – but the chlorophyll performance of the flower is still important and thus kept. Special thanks to Pavel for contributing to albiflora.eu!