“Orchideeën van de Benelux”

Karel Kreutz und Corinna Kreutz-Santen, Maastricht 8.3.2019

Turkey, Rhodes, Cyprus, Crimea – those are only some of the books about locations of orchids published by Karel Kreutz since 1998. Now he has presented a two-volume-opus about the orchids in Belgium, the Netherlands and Luxemburg: Orchideeën van de Benelux. The publication was accompanied by a symposium in Maastricht:

Among the lecturers was Daniel Tyteca of the Catholic University of Louvain, who presented the orchids of the Belgian regions Famenne and Calestienne. In the nature reserve of Lesse et Lomme alone, there are 31 species. Some of them, as Epipactis microphylla (2004), have only been proven a few years ago. Tyteca also pointed to colour variants of Anacamptis morio and Orchis mascula.

Those are shown in the book of Kreutz with special photos, as far as there are findings in the three Benelux countries. Albiflora forms are also shown of Dactylorhiza fuchsii, but interestingly not of Dactylorhiza maculata, Dactylorhiza majalis or Dactylorhiza incarnata – though there are albiflora forms of those species in other European regions. With Orchis militaris, Orchis simia and Orchis purpurea albiflora forms are also missing. Anacamptis pyramidalis is shown with a picture of an albiflora form of var. dunensis, which has been described by Londo, Kreutz and Sings in 2016. A hypochrome form of Ophrys apifera is also shown.

With regard to taxonomy Karel Kreutz is following the genus system of Daniel Tyteca and Erich Klein presented in 2008. Therefore Anacamptis morio is named Herorchis morio, Neotinea ustulata is Odontorchis ustulata. And Anacamptis laxiflora is introduced as Paludorchis laxiflora. But Kreutz is holding on to Aceras anthrophora und Listera ovata. The author concedes: Over taxonomie kan men sterk van mening verschillen – when it comes to taxonomy there are big differences of opinions. Zo is het onmogelijk om in dit werk een taxonomische indeling te hanteren, die voor iedereen aanvaardbaar is – therefore its not possible to present a classification which could be accepted by everybody. sei eine für alle akzeptable Klassifizierung nicht möglich. At least it would be desirable if the register at the end would also include the names which are used beyond the system of Tyteca & Klein.

In his opus Orchids of the Crimea, published together with Alexander Fateryga and Sergej Ivanov in 2018, Kreutz still followed the taxonomy which was developed by Richard Bateman, Alec Pridgeon und Marc Chase in 1997. The author explains the change to the system von Tyteca and Klein with their more recent genetical studies – although the conclusions are still controversial.

Next year Karel Kreutz will present a field guide Orchids of Europe, North Africa and the Middle East. Later on there is to follow a complete overview of the European orchids in ten volumes – expected for 2021/22, as it was announced in Maastricht. Since Pierre Delforge is following the taxonomic system of Tyteca and Klein since the 4. edition of his opus Orchidées d’Europe (2016), this taxonomy might achieve a broader acceptance in future.

Wolfgang Eccarius presents his genus monograph about Dactylorhiza

Die Orchideengattung Dactylorhiza

Following the benchmark books about the genera Anacamptis, Neotinea and Orchis (together with Horst Kretzschmar und Helga Dietrich, 2007) as well as a monograph about the genus Cypripedium (2009), Wolfgang Eccarius now has finished his long lasting work and has published a compendium about the Dactylorhiza orchids.

The book closes a big gap and covers a genus of orchids which is especially rich in species and quite widespread in Europe. As he has established in former publications, the author at first gives a comprehensive introduction before portraying 37 species and 46 subspecies. Eccarius explains his methodological approach and offers a summary of the research history, beginning with the plant book of Otto Brunfels published in 1534. The book abstains from giving a system to identify the species  by morphological indicators. But a tree of the genus structure based on genetical research offers a good overview about the manifold Dactylorhiza orchids and their relations.

In his description, Eccarius has taken some main decisions. He abstains from describing varieties and forms, arguing that those terms are “highly problematic” with Dactylorhiza. “The main goal of the author was a genus structure wich matches logical principles as well as the needs of observations in the field.” He stresses that’s it’s more important to differentiate between the ten sections than defining species: “With Dactylorhiza, sections are much easier to define than species.” For example, the Fuchsiae form a section of their own, together with Dactylorhiza saccifera. The section of Majales comprise Dactylorhiza majalis, Dactylorhiza cordigera and Dactylorhiza elata.

Dactylorhiza majalis subsp. calcifugiens
Photo: Peter Zschunke, 16/06/2012, bei Glæde, Dänemark

It’s comprehensible that Eccarius views Coeloglossum viride as Dactylorhiza viridis. The Viridae are presented as a subgenus, in addition to the subgenus  Dactylorhiza. Other taxonomic decisions are more thought provoking. For example when the yellowish Early Marsh Orchid no longer is a subspecies of Dactylorhiza incarnata, but an own species Dactylorhiza ochroleuca – because there are only very few hybrids between both “which justifies the treatment as a single species in the view of the author”.

Difficult are the explanations about the white flowering Dactylorhiza fuchsii in Ireland, which are elevated by Eccarius to the status of a subspecies – while most experts view the okelly taxon of Dactylorhiza fuchsii as a variety. And the morphological description of the author is not quite helpful in the field: “The subspecies is different by its lower growth” – while the photos show rather high plants. And: “The white color of flowers is shown by whole populations and not only by single plants.”

But this is also valid for Dactylorhiza majalis subsp. calcifugiens, which is presented by Eccarius only as a synonym to Dactylorhiza sphagnicola. The book shows a photo of a plant from the German region of Celle which seems to be an albiflora form of Dactylorhiza sphagnicola, but which is quite different form the calcifugiens population in Northern Denmark.

Quite useful are the explanations about Dactylorhiza maculata, which is presented as a west and northern European species, distributed also in Northern Africa and Northern Asia. The color of flower is described as especially variable, from pure white to a soft and light purple.

Eccarius understands the tendency to a color dimorphism (or polymorphism) which is typical for the genus as functionally relevant. With Dactylorhiza romana, sambucina or incarnata this phenomenon serves as a factor, “to avoid quick learning experiences of polinating insects”. This matches with the regionally different tendency of Dactylorhiza fuchsii to develop albiflora forms.

The new book makes big progress in understanding the Dactylorhiza orchids. But for a full perception there is still a lot of research necessary.

Albiflora forms of Orchis in Austria

aho29_2 Two white flowered forms of Orchis are presented by Norbert Griebl in the latest edition of “Berichte aus den Arbeitskreisen Heimische Orchideen” (29/2012, 2, p.94-110). The contribution gives an overview of the seven Orchis species in Austria and shows their distribution maps. About Orchis spitzeli he notes: “In some years white or whitish plants appear at the location in Salzburg.” The paper has a photo of a second white-flowered plant, an Orchis mascula subsp. speciosa fo. albiflora. In the same edition of the “Berichte”, Adolf Riechelmann decribes his field trip to Ibiza and mentions an apochrome specimen of Ophrys dyris, found at the southern tip of the Mediterranean island. But the main article of the edition is contributed by Werner Hahn: In the footsteps of Christian von Steven. Searching orchids and pollinators in the Crimean mountains 2011 and 2012 – an exciting study of the orchid flora of the peninsula and as well as of a special chapter of the history of botany.

Orchids are not a young plant family at all

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.”

Snap-shot of the evolution: preliminary report of albiflora studies

Peter Zschunke: Albiflora-Formen der Orchidaceae - mehr als eine Laune der Natur
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.

Dactylorhiza cyrnea – a new species described on Corsica

Two specialists of the orchid flora on Corsica, Wolfram Foelsche and Klaus Cord-Landwehr, have described a new Dactylorhiza species: Dactylorhiza cyrnea belongs to the group of Dactylorhiza maculata and shares its characteristics of a tetraploid set of chromosomes. In their article “Dactylorhiza cyrnea und die Taxa der Gattung Dactylorhiza auf Korsika”, published in the Journal Europäischer Orchideen (Vol. 44, Heft 1, April 2012), the authors review the findings of Dactylorhiza insularis, Dactylorhiza sambucina and Dactylorhiza saccifera on Corsica and note that there is no Dactylorhiza majalis confirmed for this Mediterranean island. The plants described as Dactylorhiza cyrnea is morphologically similar to the diploid Dactylorhiza fuchsii. They are rather elongated and grow in humid locations. The leafs are mostly vaguely spotted but may also be unspotted. The flowers have a markedly thin spur (contrasting the thick spur of D. saccifera) which is shorter than the ovary. Their colour is a bright pink, with a purple labellum pattern. The population described by the authors “offers a very consistent appearance” – but there are also white flowered plants occasionally, the authors note. The photo above on the right, generously sent to me by Wolfram Foelsche, is also included in the article.

Description of new species: No Latin required anymore

Caroli Linnæi ... Flora zeylanica: sistens plantas indicas Zeylonæ insulæ ...
Caroli Linnæi ... Flora zeylanica: sistens plantas indicas Zeylonæ insulæ ...1747

With beginning of the new year, the international botanical community has dismissed two requirements in describing new species or other taxa. It is now no longer necessary to include a Latin description of the plant, and the article describing a new species must not be printed, but can also be published online. “Beginning 1 January 2012 names of new plants, algae, and fungi may now be published with a validating diagnosis or description that is written in either Latin or English”, says an article which explains the decisions of an international botanical congress in July in Melbourne. The rules of introducing valid taxa are stated in International Code of Nomenclature for algae, fungi, and plants (ICN).

Colour influences pollinator behaviour

The Flower of the European Orchid

Form and function of the flower organs are the main focus of the new fascinating book The Flower of the European Orchid by Jean Claessens and Jacques Kleynen. Illustrated by great macro as well as microscopic photos this important opus presents a comprehensive description of the structure of orchid flowers with the different European genera. In a foreword, Richard Bateman writes: „No other family of plants can match the orchids for their sheer charisma“. But the excitement goes along with a certain scientific pain – Bateman stresses that there still remain major scientific uncertainties which „further torment us“ – among them questions of evolutionary adaptation.

The orchids’ strategies of fertilization are manifold and the book explains how the specific construction of the column (gynostemium) supports allogamy by pollinators or autogamy (self-fertilization). Especially intriguing are the strategies of Dactylorhiza, Orchis and other genera without any nectar in the spur. Claessens and Kleynen explain that the pollinators of Orchis mascula are „recently emerged, naïve bees or exploratory insects that have not yet learned that the flowers offer no reward” (p. 220). The authors also cite the study of L. Dormont, R. Delle-Vedove, J.-M. Bessière, M. Hossaert-Mc Key und B. Schatz about the presence of white-flowered Orchis mascula which underlines „the importance of visual cues for attracting pollinators“ (p. 220).

In the Dactylorhiza chapter the authors write: „Colour can also influence pollinator behaviour“ (p. 240). With regard to the red and the yellow forms of Dactylorhiza sambucina they refer to experiments showing that experienced bumblebees „preferred by far the morph that most resembled the rewarding plant on which they have fed previously“. Vice versa it may be presumed that there may be a form of evolutionary adaptation directed to develop visual cues which are different from non rewarding plants being abundant in a certain region – as it could be the case in Western Ireland with the many white-flowered forms of Dactylorhiza fuchsii on meadows with earlier flowering Orchis mascula.

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.

Albiflora plants influence naïve pollinators

White-flowered orchid varieties are not just a “freak of nature” – they have quite obviously some biological function. A group of scientists in Montpellier in Southern France has found that the existence of albiflora plants in a population of Orchis mascula is connected with a much higher fruit set of the purple-flowered plants than in populations where there are no white-flowered Orchis mascula:

“Surprisingly, our study showed that the presence of co-occurring white-flowered individuals led to significantly higher reproductive success of nearby purple-flowered individuals (mean fruit set 27%), while white-flowered plants themselves had the same low fruit set (6%)”, the authors of the study – L. Dormont, R. Delle-Vedove, J.-M. Bessière, M. Hossaert-Mc Key and B. Schatz – wrote in their article in New Phytologist (2010) 185: 300–310. The flowers studied – overall 11 709 at 805 plants – showed almost the same increased fruit set when the researchers planted some ping-pong balls which mimic the white Orchis mascula inflorescences: “The effect was virtually identical in magnitude (fruit set increased from 6 to 27%), whether the nearby white-coloured object was an O. mascula inflorescence or a ping-pong ball.” The nearer a purple-flowered plant to the white colour, the higher was the fruit set developed due to a successful pollination.

The authors explain their surprising results with pollinator behaviour after visiting Orchis mascula who belongs to the food-deceptive orchids: “It seems plausible to suppose that after unrewarding visits to purple flowers, naïve pollinators probably avoid homogeneous populations of purple flowers, and may then preferentially orient to a different colour or to a colour contrast such as a mix of white and purple flowers.” Pollinators of Orchis mascula are bumblebees (Bombus, Psithyrus), solitary bees (Eucera, Nomada, Andrena, Apis) and the beetle Cetonia aurata.

The albiflora varieties are quite rare in the populations studied in Southern France: The authors counted 0.9 to 1.4 percent in different populations. But this is much higher than the percentage which could be assumed in the case of spontaneous mutations affecting floral pigmentation genes with an average of just 0.1 percent. Regarding the higher percentage of albiflora varieties with Orchis mascula the authors state that “it is unlikely that such high frequencies could be the result of repeated spontaneous mutations alone” – and this should also apply to the case of other orchid species with a higher percentage of white-flowered plants like Anacamptis morio or Dactylorhiza fuchsii in Western Ireland.

The white-flowered Orchis mascula themselves have only a low fruit set, but they “help” the purple-flowered plants of their species to be pollinated. “In O. mascula, the presence of whiteflowered variants might be regarded as an adaptation that benefits the purple-flowered relatives of white-flowered morphs, rather than providing a direct benefit to whiteflowered individuals”, the authors wrote and assumed that there is some “mechanism of kin selection” responsible to grant a higher percentage of albiflora plants.

The scientists in Montpellier are pursuing their research with other species as well. Laurent Dormont wrote me that they have also studied white-flowered plants of Calanthe sylvatica on the Caribbean island of La Réunion (the results to be published in Plant Systematics and Evolution and also the floral volatiles of white-flowered orchis species.