Orchid conference in Neumuehl: Rescue mission in Switzerland

An unusual rescue mission in the canton Zurich was subject of the 2018 orchids conference in Kehl-Neumuehl, Germany. In this Swiss region, nutrient-poor grassland and bright forests have been dramatically reduced, René Gaemperle explained. Reasons are – as in other regions – the over fertilization of the intense agriculture and the increased building activity: “Where the hills are most beautiful, country residences are built”, Gaemperle said.

In order to strengthen weak populations like Ophrys araneola, Gaemperle cooperated with officials and organized manual pollination, collection of seeds, mixture of seeds with river sand and sowing. If the appropriate symbiosis fungus is in soil, this method works rather soon, explained Gaemperle. The time from sowing to first flowering is just three to six years.

He chose a different method with Anacamptis coriophora: Seed capsules from the Lake constance habitat Wollmatinger Ried have been sent to an expert for in vitro culture in Sweden. The young plants have then been planted at seven places in canton Zurich, overall 525 plants until 2015. In this year 56 of those plants have flowered, Gaemperle told. When species are threatened by extinction, such methods are the only way to save them. “If we don’t act now, they will vanish forever.”

Threatened orchid species are also an issue for Peter Steinfeld who lectured about the nature reservate Bliesgau in the German state of Saarland. Steinfeld has been observing the changes of the regional flora for 35 years. According to him, Cephalanthera rubra is threatened by extinction in Saarland – he found the last flowering plants  in Bliesgau about 20 years ago. Heavily decreasing is also Dactylorhiza viridis. But Limodorum abortivum is expanding, probably coming from the French region of Lorraine. The same case is with Ophrys sphegodes and Orchis simia. As another “profiteer of climate change” Steinfeld named Himantoglossum hircinum. Climate change was also the subject of my lecture with impressions of this summer on Gotland, Sweden. Jean-Marc Haas also reported about dried out places in Uzbekistan.

At the conference with more than 60 participants from four countries, which was organized by Harald Baumgartner and Hubert Heitz, Helmuth Zelesny lectured about a field trip to the Golzentipp mountain in Eastern Tyrol, with colour variants of Nigritella rhellicani in white, yellow and carmine. In this region at the edges of the Lienz Dolomites Gymnadenia conopsea is also quite often white-flowered. Hybrids of both species display a big variety of forms. Not so common is the hybrid of Gymnadenia conopsea with Pseudorchis albida. Nigritella rubra is flowering on lime stone. The variety of the orchid flora on this Alpine meadows has also been described by Norbert Griebl in his paper published by AHO-Berichte.

Helmut Presser lectured about new taxons related to Ophrys holoserica and Ophrys scolopax in France as there are Ophrys demangei and Ophrys quercophila, the oak loving Ophrys. Hartmut Moeller again showed impressive photos of pollinators, this time he observed Epipactis palustris with potter wasps, bumblebees and beetles.

Orchids “adapt” to colour preferences of pollinators

This hypothesis has been formulated by Hannes Paulus in a contribution for the latest edition of the Journal Europäischer Orchideen (Hannes F. Paulus: Zur Bestäubungsbiologie der Gattung Ophrys in Nordspanien: Freilandstudien an Ophrys aveyronensis, O. subinsectifera, O. riojana, O. vasconica und O. forestieri. J. Eur. Orchideen. 49 (3-4): 427-471).

In this article the author studies both populations of Ophrys aveyronensis in Southern France and Northern Spain – the last one termed as Ophrys aveyronensis subsp. vitorica. According to Paulus it is just one species, because both are pollinated by the bee Andrena hattorfiana.

Paulus points to the fact that this bee is specialised on the widow-flower (Knautia). The pink inflorescence of this plant has the same colour as the perigone, i.e. the sepals and petals, of Ophrys aveyronensis. The expert of Ophrys is stating: It can be expected that this is not just a mere chance but an adaptation to the main nourishing plant of the pollinator. Knautia shows at the same time more deeply pink flowers as flowers tending to white.

This evidence is confirming the approach to also look for other plants when we search for reasons why albiflora forms of different orchid species are more often in certain places.

Ophrys pigmentation demonstrates bilateral symmetry

While travelling in Attica, Greece, Marco Klüber photographed this special Ophrys helenae which demonstrates the bilateral symmetry of orchid flowers. The left half of the lip shows the regular red-brown coloring while the right half is hypochrome, with a partial loss of pigments. The lighter red hues are preserved, in addition to the chlorophyll in the lower edges.

Orchid flowers have a bilateral symmetry – as it’s the case with beetles or the human face elsewhere in nature. Other plants like the flowers of liliaceae have a radial symmetry with three or more mirror lines.

On his trip Marco also saw the albiflora form of Anacamptis papilionacea subsp. messenica (formerly subsp. heroica):

orchids conference in Sundheim 2: Floral photosynthesis

Why are Ophrys flowers with a defect in pigment production yellowish-greenish and not white as it’s the case with Orchis, Dactylorhiza or other genera? I’ve tried to give an answer to this question at the orchids conference in Sundheim (Germany), in a lecture titled The Ophrys flower – more than an invitation to pseudo copulation.

Ophrys holoserica
Ophrys holoserica

My assumption: The lips of all Ophrys flowers are green – but in most cases we can’t see it, because the chlorophyll in the lips is covered by anthocyanins. Only if the production of anthocyanins is disturbed, the chlorophyll in the Ophrys lip is visible, often together with yellow pigments. Only the marking of the labellum is free of those pigments, it appears in the case of a defect in Anthocyanin production as white. But even in the lower segments of the bluishly shining marking of Ophrys speculum researchers have showed the existence of chloroplasts, of cell plastids with chlorophyll. The bluish color comes from the vacuoles of the epidermis which are filled with cyanidin pigments, while the brown rest of the labellum in addition contains delphinidin, quercetin and anthocyanin pigments.

The Ophrys forms without anthocyanins cannot be termed as white-flowered or albiflora. It makes more sense to call them hypochromic in the meaning of a underdeveloped production of color pigments.

Those forms have been found with more than 20 Ophrys species.

Near the Swiss town of Basel there is a whole population of Ophrys apifera plants without anthocyanins in the labellum. Those plants have been described as Ophrys apifera var. basiliensis.

Anthocyanins also acts as a sun protection. They have the ability to absorb damaging light energy as UV UV radiation. The water-soluble anthocyanin pigments are in the vacuoles of the plant cell, which also contain water and nutrients. This protective function of the pigment is especially important for plants in Southern Europe.

In general, the petals of flowering plants don’t have chlorophyll. The tissue of their flowers and fruits don’t have chloroplasts (those cell parts which contain chlorophyll and therefore are green), but chromoplasts. Those don’t have chlorophyll, but for example carotenoids: yellow, orange or red color pigments.

Only in the early bud stadium some flower plants still have some amounts of chloroplasts – later, those develop to chromoplasts or colorless leucoplasts with the function to store proteins or starch – this process has been explored in an interesting report by Kevin Pyke and Anton Page. The same transformation can be observed when tomatoes are ripening – the fruit is green at first, with many chloroplasts and chlorophyll, which later change to chromoplasts with the red lycopene pigment.

The cells of green leaves have about 20 to 50 chloroplasts with chlorophyll. They are filled with stroma, which also contains the enzyme Ribulose-Bisphosphat-Carboxylase/Oxygenase (RuBisCo). Together with water and sun light, this enzyme has a decisive role in transforming carbon dioxide in glucose: from CO2 and H2O to C6H12O6.

Studies have demonstrated that orchids of sunny meadows in the Mediterranean can be viewed as mycoheterotrophic: They get at least a part of their nutrients from fungi. Since fungi can dissolve the nitrogen (which is important to produce enzymes) of the soil much better than higher developed plants, mycoheterotrophic orchids have a better nitrogen supply than other plants without this special relationship. The different orchid species have different relationships with fungi, but many orchids rely on fungi of the genus Tulasnella.

Additionally, Ophrys orchids make use of the fact, that they have chloroplasts in their flower tissue, so photosynthesis becomes possible in the flower. Some Ophrys species also have intense green petals – in contrast to the labellum there are no anthocyanins in these petals which would otherwise cover the chlorophyll.

It can be assumed that Ophrys flowers make use of the Crassulacean Acid Metabolism (CAM). This mechanism of photosynthesis, named after the family of the Crassulaceae, is especially adapted to hot and dry places.

The advantage of this CAM photosynthesis compared with the standard C3 photosynthesis: The plant cells receive carbon dioxide at night. Then, the stomata of the plant tissue are open. In the daily heat they can be closed, so the plant is protected from dehydration. The CO2 received by night is stored in the vacuoles of the cell in form of malic acid. By day, it will be transformed to carbon dioxide and oxygen by the help of light energy. The CAM photosynthesis only needs less than a fifth of the water amount which is normally necessary in the case of C3 photosynthesis. Therefore, the plant can survive in dry times and is protected against lack of water.

cam_photosynthese_nacht

Einfaches RGB

There are also plants with a facultative CAM photosynthesis: the water saving mode will only be used in dry summer times. In spring, the budding plants still use the C3 photosynthesis. While CAM has the advantage of a lesser water consumption it also has a big disadvantage: The production of biomass is quite lower. CAM plants grow much slower than C3 plants.

Most orchids with thin leaves use a C3 photosynthesis. Among them are the genera Orchis, Dactylorhiza, Anacamptis and Neotinea. Those with thick leaves can master CAM photosynthesis, for example the tropical genera Phalaenopsis, Cymbidium or Cattleya.

Since CAM plants have to store CO2 by night in order to enable the daily photosynthesis, they have enlarged vacuoles. Thick leaves can store more organic acid which conserves CO2 in night time. It may well be that this is also the case with the floral photosynthesis of Ophrys. One clear sign is the thick Ophrys labellum – the form which also has its special function to imitate female pollinators to induce pseudo copulation. The often low height of Ophrys is an additional sign that those species are at least facultative CAM plants, since there is less biomass produced.

An advantage of the floral photosynthesis is the ideal position of flowers to the sun light. The higher amount of light energy absorbed enables a higher capacity to store CO2. Though there is no detailed research yet, there are many signs that especially the Mediterranean Ophrys master a floral photosynthesis. The CAM metabolism enables them to survive in dry climates, on rock grounds, with early withering leaves. The evolution of the Ophrys labellum fulfilled two functions: the adaption to pollinators and the ability of floral photosynthesis.

A cycle of vegetation becomes visible which determines the life of Ophrys. There are four phases which are adapted to specific environment conditions and biological demands:

ophrys_phasen

The seedling is developing under conditions of a mycoheterotrophic supply with nutrients. Developing the first leaves, photosynthesis becomes possible. It can be assumed that the C3 mechanism of photosynthesis is still dominant, since temperatures are moderate in spring and there is enough water. And the plant needs to grow quickly, to build up biomass. Here the C3 photosynthesis has a clear advantage.

The budding plant is still growing, the leaves reach their optimal capacity for C3 photosynthesis.

Beginning with flowering the leaves begin to wither. So the flower starts its additional CAM photosynthesis and secures a sufficient supply with nutrients even under conditions of increasing heat and drought.

When the fruits ripe there is again a phase when biomass has to be added. But the capacity of photosynthesis is decreasing when the flower is withering. Now the role of the mycoheterotrophic supply with nutrients might become more important again.

a dream in green and white: Ophrys apifera in Basel

Finally, I’ve met her: The bee orchid at the Rhine port of Basel which has been described as Ophrys apifera var. basiliensis – in 2006, Paul Delforge “downgraded” her to Ophrys apifera f. basiliensis.

Ophrys apifera var. basiliensis

My Swiss friend Klaus Hess has told me a couple of years ago about this special population of bee orchids. Now we met at Basel and took the bus to a place called Waldhaus. There, we walked to the bank of the Rhine. Between the railway tracks and the river, limited between the container terminal to the West and the old Auhafen to the East, there is a small strip of grassland quite rich with species. Dominated by Bromus erectus, there is also growing Knautia arvensis, Geranium pyrenaicum, Leucanthemum vulgare and other flowers.

Basel Rheinhafen

Soon Klaus found the first of these special bee orchids. They are special not only due to their lack of pigments, but also to the special form of the petals. Those are sepaloid, much longer and broader than usual with bee orchids. We are just in the beginning of the flowering time. As Klaus was looking for further plants I studied the flower with my camera – and observed the rare visit of an Andrena bee at a bee orchid. It was just a visit, not a pollination at all, though the bee carried pollen from other flowers. Ophrys apifera is autogamous, and the yellow pollinia are soon falling down to perform self fertilisation.

Ophrys apifera var. basiliensis

The next surprise on this Ascension holiday was meeting Stefan Schwegler, who has described those bee orchids as Ophrys apifera var. basiliensis (in: Orchid Review 112/2004).

Basel Rheinhafen

He showed us a couple of other plants, among them a regular Ophrys apifera with its brown and yellow pigments as well as Platanthera chlorantha, Anacamptis pyramidalis and Dactylorhiza fuchsii. And he told us about the permanent struggle to conserve this special place against commercial interests of the port management. The population of Ophrys apifera var. basiliensis is declining, Stefan Schwegler explained, but still consists of about 100 plants. Most of them don’t flower every year, but wait for their moment to appear.

on the trails of Ignaz Friedrich Tausch

On the occasion of a visit to Prague I looked up some specimens at the Charles University Herbarium (PRC). In order to help a friend, I searched for the holotype of a plant which was described by the Bohemian botanist Ignaz Friedrich Tausch as Ophrys purpurea (Flora; oder, (allgemeine) botanische Zeitung. Regensburg, Jena 1831) – now regarded as a synonym of Ophrys apifera or as Ophrys apifera var. tilaventina. The holotype was said to be in the herbarium in Prague, so I searched several packages of Ophrys specimen there, with the much appreciated help of PRC’s curator Jan Stepánek.

The holotype of Ophrys purpurea was not there, but I found an interesting specimen collected by the French botanist Jean Michel Gandoger (1850-1926):
Ophrys apifera
The description carries the information that Gandoger collected this plant in 1879 near Algier as Ophrys apifera f. elata, formerly described by Tausch as Ophrys purpurea:
Gandoger specimen

At the end of my visit I searched a further package of specimens with dried Orchis plants – hoping to find a albiflora specimen. Instead I detected a specimen collected by Tausch as Jan Stepánek confirmed by examining the hand-written label with the nomber “1470” attached to the stipe of the plant:
Orchis mascula
A further label written by an unknown person has the information: “Orchis mascula L. vom berge Rhadisken bei Leitmeritz” – this information matches the catalogue of “Fundorte der Flora Boehmens nach weiland Professor Ignaz Friedrich Tausch’s Herbarium Florae Bohemicae alphabetisch geordnet von Johann Ott”, published 1859 in Prague:

So who was this Ignaz Friedrich Tausch? The Bohemian botanist was born on January 29th, 1793, in Udrči near Karlovy Vary. After his thesis about “De inflorescentia” (1835) he was director of the botanical garden of duke Canal de Malabaillas in Prague. He studied a broad spectre of plants and published “Bemerkungen über einige Arten der Gattung Paeonia” (1828) as well as his Flora Bohemiae (1831). Tausch was all his life rather poor, Stepánek told me. So he sold dried plants ot different herbariums. Tausch died on 8th September 1848 in Prague.

Sundheim Orchid Conference 2012

Sundheimer Orchideenkonferenz
Two great publication projects about European orchids are being prepared which will meet high expectations. At the 16th Orchid Conference in Sundheim (near Kehl, Southwest Germany), Wolfgang Eccarius offered a first look into his project of a monography about the genus Dactylorhiza – the planned publication year will be 2015. Among the about 50 participants of the conference, coming from Germany, Switzerland, France and the Netherlands, was Karel Kreutz who is working on an opus of 6 to 7 volumes about all the orchids in Europe, which is expected to be published probanly in 2016.

At the beginning of the meeting, Helmut Baumann showed a series of impressive videos showing pollinators of different orchid species. Helmut Presser presented photos of his latest Greece journey, Peter Goelz showed pictures taken at two different locations of Ophrys kreutzii in Turkey and the Essink couple shared impressions from Rhodos.

Wolfgang EccariusIn my contribution about “Colour polymorphism with Dactylorhiza – Evolution as a continuing process” I presented my studies about Dactylorhiza fuchsii and the calcifugiens location in Northern Danmark. After a partly controversial debate, Wolfgang Eccarius talked about the specific difficulties of his Dactylorhiza project. The common genetical methods to differentiate between species, such as the construction of cladograms by means of an analysis of the DNA’s ITS regions, may be used only with great caution in this case, he said. “This doesn’t function at all”, if a species has developed from two species. Therefore, he intends to base his book of about 600 pages on a rather broad concept of species. At the beginning, there was a comprehensive study of literature, including about 1100 protologues (original decriptions). “This fact alone implies that the nomenclature of this genus will be a giant challenge”, Eccarius said. In order to concentrate on the essentials, he only wants to present species and subspecies in length, without ignoring varieties. “I succeeded in looking into all typesheets”, Eccarius said – with one exception: “I’m still missing the typesheet of Dactylorhiza incarnata subsp. baumgartneriana. The typesheet cannot be found in Stuttgart, where it is said to be.” This subspecies, described by B. and H. Baumann, R. Lorenz and R. Peter in 2003, later described by Kreutz und Sebastian Sczepanski as Dactylorhiza kafiriana subsp. baumgartneriana, is named after Harald Baumgartner, the organiser of the Sundheim Orchid Conference.

Richard Bateman on stability and change

Richard Bateman
Still looking for any hints to shed some light on the albiflora phenomenon, I visited Richard Bateman in London. The white-flowered morphs “are of greatest interest to me because of their relative frequencies in the diploid and the tetraploid groups of Dactylorhiza”, he told me. “If your mind works its ways through the different diploids – incarnata, fuchsii, sambucina – they all show colour polymorphism. And they all have a certain number of very pale or white individuals.” Quite different are the observations with tetraploid Dactylorhiza species like praetermissa, majalis or alpestris. Bateman noted: “I’ve only found one albino praetermissa and one albino traunsteinerioides in 30 years of going in the field.” Quite younger is the albiflora.eu project – but up to now only some scattered findings of white-flowered Dactylorhiza majalis have been reported – and none of praetermissa or traunsteineri. As a possible explanation Bateman noted: “Presumably, in the tetraploids there has to be a minimum of four copies of a gene that is malfunctioning to cause the albinism. So I think the tetraploids are buffered against albinism by having additional copies of the genes that generate the anthocyanin pigments.”

Arguing with him about the negative connotations of the term malfunction, Bateman answered: “Most organisms are ‘designed’ to remain the way they are and not to change [substantially]. So, from a genetic viewpoint, any change that is expressed is a malfunction. I agree the malfunction could be beneficial rather than negative but most times it’s negative.”

Bateman’s main interests in research are the questions of speciation or at least the question of what might lead to evolutionary divergence between populations: “The genus level – for me at least – is solved. The species level interests me the most now. That’s were the most challenging topics still have to be addressed – how orchids speciate.” Despite a huge literature on the topic, Bateman noted, those questions are still not adequately solved. “Each time I address a particular set of orchids, the answer [to this question] is different.” So up to now, no generalization is possible. But, Bateman said, “I strongly believe that the importance of pollinator [specificity] is being exaggerated by a lot of workers.”

At least one general observation can be stated according to Bateman: “New [evolutionary] strategies are tried out constantly – more than most people believe – but I think they succeed less often than most people believe.”

In addition to such reflections on stability and change in the genetics of orchids, we wondered why hypochrome forms of Ophrys are rather green than white – obviously the Ophrys flowers still contain chlorophyll even if they lack the anthocyanins – and with good reason: “The rosette leaves of Ophrys (and Himantoglossum as well) tend to be dead before the flowers properly open”, Bateman said. “So I don’t think there is much supply of nutrient coming from [root to flower]. The flower has become autonomous … whereas in Orchis or Anacamptis the flowers are far less independent.” So, Ophrys flowers are quite special. “One of the most striking things when you start working on the flowers, cutting them up looking at them under microscope, you realize how much energy is invested in an Ophrys flower. There is a lot of tissue.”

After the visit, the Royal Botanical Gardens in Kew have been the very right place to further contemplate on the miracles of nature. (With thanks to Richard Bateman for reviewing his quotes, additional notes are marked with brackets)
Kew Gardens

Ophrys speculum f. flavescens

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.

Cephalanthera rubra f. albiflora revisited

Cephalanthera rubraThis year I had the chance to visit the white flowering form of Cephalanthera rubra in the Hesse part of the Rhoen some days earlier than last year. But first I followed a hint and looked up a place further in the South, near Ahlersbach. Quite near a path through the forest a white Cephalanthera rubra with a slight hue of pink! The pink colour is well visible in the buds, where the remaining pigments are more concentrated than in the opened flower.

Cephalanthera rubraAt the second place near Huenfeld, characterized by an old beech mentioned by Marco Klueber in his great book about “Orchids in the Rhoen” the albiflora plants of Cephalanthera rubra are splendidly flowering. The Swedish botanist L. Anders Nilsson showed (in an article in Nature, 1984) that Cephalanthera rubra mimics the floral coloration of Campanula in the visual system of bees in order to be pollinated by them, especially by male bees of the genus Chelostoma. Since Cephalanthera rubra is flowering before Campanula, they are quite attractive for the bees. It would be interesting to see how bees are reacting to the albiflora forms of Cephalanthera rubra.

With regard to pollinators my visit on June 24th had a special highlight when I saw a wasp (Argogorytes mystaceus) pollinating Ophrys insectifera. The insect pseudocopulated two flowers in a timeframe of more than seven minutes.