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Saturday, January 02nd, 2010 | 

In OrchideenJournal 3/2009, Josefa and Richard Thoma describe how they have found two white flowering plants of Orchis spitzelii for the first time in a region they have been visiting for about 20 years. This location in the Alps near Salzburg is the only place where Orchis spitzelii can be found in Austria.

In June 2009, the couple counted 17 plants when Josefa was surprised to find two white flowering Orchis spitzelii. “I didn’t trust my ears”, writes Richard Thoma describing his feelings when his wife exclaimed: “Two whites!” The author named the rare color variation “Orchis spitzelii f. albovirida” – with regard to the green perigone containing chlorophyll pigments.

“Why now, of all times?”, Thoma asks and is looking forward to next year when the want to see if the white forms appear again.

Maybe it’s more than just a “freak of nature” as Thoma is assuming. More substantial research is needed to see if there is a certain function which could explain why certain orchid species develop albiflora forms. Special thanks to Richard Thoma for contributing his photos of the white flowering Orchis spitzelii to albiflora.eu.

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Friday, December 18th, 2009 | 

… develop white flowers while their species is supposed to have coloured flowers. This Gentiana germanica, found at Seiser Alm in the Dolomite Alps, is an example.
Gentiana germanica f. albiflora
The plant at the right side has flowers without pigments (anthocyanins). It may be viewed as “Gentiana germanica albiflora”, as Ferdinand Schur has noted in his article “Beitraege zur Flora von Wien” (Oesterreichische Botanische Zeitschrift vol. 11/1860). The correct name should be Gentiana germanica f. albiflora.

Another example found this year in the Swiss region of Aargau is Ajuga reptans f. albiflora which has acquired some horticultural importance.

Ajuga reptans f. albiflora

But neither the Gentianaceae nor the Labiatae (the family of the genus Ajuga) could be viewed as a family with a certain tendency towards developing white flowers – as it is the case with orchids. Maybe another family with an albiflora disposition are the Cactaceae. A charming web gallery of albiflora cacti has been set up by Gerd Weiss presenting more than 50 species.

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Friday, December 04th, 2009 | 

A new publication presents a showcase of all the orchids to be found in the Rhoen Region of central Germany. In this book, the author and photographer Marco Klueber presents a summary of his research in this hilly region. He explains how geological and geographical conditions formed different habitats as there are several types of forests, grassland and marsh areas.

There are 48 different species of orchids growing in this region or confirmed to have been grown there in past times. There are five species which can’t be found today in the Rhoen. Their presentation is a memorial and at the same time a challenge to do everything to preserve these treasures of nature. And Klueber’s publication is an important contribution to such efforts. Only public awareness offers the basis for the necessary political decisions to protect those regions.

In addition to the presentation of the region there is an introduction to the family of orchids and its biological specialties. The main part of the book are in-depth profiles of all species with great photos. The author also presents several albiflora varieties such as Dactylorhiza fuchsii, Orchis purpurea or Cephalanthera rubra. Marco Klueber has also made important contributions to this web site. At the end the book presents six proposals for hiking tours where you can find orchids. (Marco Klueber: Orchideen in der Rhoen. Kuenzell-Dietershausen, edition alpha 2009. 256 pages. 23.90 Euro)

Orchideen der Rhoen

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Sunday, October 18th, 2009 | 

In an e-mail exchange following his recent article in the Journal Europaeischer Orchideen (JEO), Richard Bateman, orchid specialist at Kew Gardens, wrote me that albiflora plants “are far more common among diploid Dactylorhiza species than tetraploid species”. A possible reason might be the “buffering of mutations by having four comparable genes in the tetraploid chromosomes”. Diploid species (with 40 chromosomes) are Dactylorhiza fuchsii, D. incarnata and D. sambucina. Tetraploid species (with 80 chromosomes) are D. majalis, D. praetermissa, D. maculata, D. elata, D. sphagnicola and D. traunsteineri.

Albiflora plants of Dactylorhiza fuchsii are quite often observed, and in Ireland there is also the intriguing D. fuchsii ssp. okellyi which is diploid as well. D. incarnata and D. sambucina are known for their colour dimorphism: red and yellow with D. sambucina, purple and yellowish-white with D. incarnata and its var. ochroleuca. In a recent article in the Annals of Botany (2009), Mikael Hedrén and Sofie Nordstroem presented the results of their reasearch about the colour dimorphism with D. incarnata. They observed that there was “no clear pattern of habitat differentiation … among the colour morphs”. With D. incarnata var. ochroleuca “the lack of anthocyanins is probably due to a particular recessive allele in homozygous form” – the diploid chromosome set has both alleles determining the lack of purple in the flowers.

Besides genetics, colour also affects the pollination function of orchid flowers. Bateman wrote me that “in at least a few cases, instantaneous loss of anthocyanins (or even just radical decrease in anthocyanin production) must affect pollinator preference, and lead to lineage divergence”. A potential example of such an evolutionary process could be Gymnadenia frivaldii as a relative of Gymnadenia conopsea.

But in general the question of a certain functionality of colour change is still unanswered. Following his mentioning of white flowers in the above mentioned JEO article, Bateman wrote me it would be “more correct to use the term ‘parallelism’ rather than ‘convergence’, since in most cases no-one has demonstrated a change of function or ‘behaviour’ in the abnormal white flowers”. He further noted “the probability that many different mutations and epimutations generate white flowers”. Recognising that there are quite many open questions, Bateman also asked “whether white is actually a colour at all”, pointing to the “very simple shifts between ‘white’ flowers and ‘green’ flowers in Platanthera”.

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Saturday, October 10th, 2009 | 
Model of phylogeny and classifying existing plants, by Robert Bateman

Model of phylogeny and classifying existing plants, by Robert Bateman

In an essay about the taxonomic mess with European orchids, Richard Bateman stresses the importance to develop clear criteria for classification instead of individualistic conclusions. The article titled “Evolutionary classification of maximising explicit evidence and minimising authoritarian speculation” (In: Journal Europäischer Orchideen, Vol. 41/2, July 2009) explains how a monophyletic classification (i.e. a classification with a group of organisms forming a clade with a common ancestor and comprising all the descendants of this ancestor) can be derived from the phylogeny (evolution) of species.

Bateman recognises the value of morphological characteristics, but stresses that molecular data should be the main source for a scientific taxonomy. He criticizes that other classifications are often only “the result of personal opinion” and says: “21st Century data are being constrained by voluntarily retaining an 18th Century approach to biological classification”. Regarding taxonomic debates about the genera Dactylorhiza/Coeloglossum, Neottia/Listera or Gymnadenia/Nigritella he complains: “Authors decide which names they will accept and which they will reject from the many classifications already available, as though they were selecting products from the supermarket shelves.”

Arguing for clear rules founded on molecular research, Bateman also mentions the “origination of white-flowered individuals in many orchid lineages” as a result of a convergent evolution – this term describes the development of similar features with species who have no genetic relationship, often initiated by functional or environmental adaptation. But is there really such an adaptation when orchids develop white flowers, “achieved by suppressing any one stage in the biosynthetic pathway that generates anthocyanin pigments”? And what would be the object of such an adaptation?

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Friday, October 02nd, 2009 | 

“The palette of colors in nature is almost infinite”, says the botanist Hilke Steinecke of the Palmengarten in Frankfurt. There, this palette is displayed in an exhibition which can be visited until November 1st. The exhibition also explains the role of pigments in the colors of flowers and how fertilizing insects see colors.

An interesting demonstration shows the acid sensitivity of anthocyanins. When a drip of vinegar is placed on the violet flower of  Ipomoea, its color changes to pink. “In an acid milieu many anthocyanins are rose-pink, in an alkaline milieu blue”, as it is stated in the catalogue. This phenomenon could also explain the color variations of Nigritella nigra ssp. rhellicani in the Dolomite Alps – these occur especially in a region with rather acid soil.

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Thursday, July 23rd, 2009 | 



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.

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Wednesday, July 22nd, 2009 | 



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):

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Sunday, June 28th, 2009 | 

Following the hint of an orchid friend, today I’m travelling to the Hesse part of the mountain region Rhoen. Northeast of Fulda, near Huenfeld, a path is leading through a long stretch of forest. Along a slope there are flowering countless Cephalanthera rubra. And directly at the path there are three plants with white flowers. Die first still has a slight violett hue. The second is totally white, but already slightly withering, and the third has only one, relative closed flower.

Along the slope there are more than one hundred Cephalanthera rubra, Gymnadenia conopsea and Epipactis atrorubens. There is one Gymnadenia conopsea flowering almost white, with a last hue of violett in the flowers.

South of Fulda and west of Bad Brueckenau we follow another hint and find a hilltop with an impressive  grassland vegetation. In the lower range there are numerous Gymnadenia conopsea. Farther above, some meters from the forest, there are Epipactis atrorubens flowering – and among them some plants, which are not flowering red-brown, but yellowish-green! While strolling this wonderful slope, I’m seeing a white flowering Gymnadenia conopsea var. albiflora! It is a strong plant with more than 30 flowers, the upper ones still as buds. On the hill there are many butterflies and wild bees. The white flowering Gymnadenia is offering them with its spur filled with nectar as an interesting alternative.

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Monday, April 27th, 2009 | 

 

The new orchid season has begun, and the white flowering Orchis militaris in my neighborhood is already showing its buds. This year, there might be several “albiflora” plants at this place. The plants seem to be healthy and strong. The long winter was no problem for them, and there was enough humidity in March and April.

 

Afterwards I visited a meadow in the Rheingau, the region west of Wiesbaden, with plenty of Anacamptis morio. I estimate that there are about 800 plants, 5 of them with white flowers. This would mean a ratio of 6 Anacamptis morio “albiflora” per 1000 plants – a bit higher than my general estimation of 3 to 5/1000. This confirms that Anacamptis morio has a high tendency to develop white flowers. Today, most Anacamptis morio on the meadow are in full flower. But it’s remarkable that the blossom of the white flowering plants is quite advanced. Some flowers are damaged, especially at the spur (photo). Two years ago, on 6 May, I’ve been at this place near Johannisberg the last time. I didn’t observe this phenomenon at that time. On the lower meadow some Orchis mascula were growing then, which I couldn’t find today

At last I was visiting a place in the Wisper valley as I’ve heard that there had been several white flowering Orchis mascula. In the mixed oak forest I find about 25 mascula in the purple standard colour, but no albiflora forms.

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