field trips – albiflora

Albiflora orchids on Gotland

There have been a couple of botanical travel reports from Gotland with findings of white-flowered orchids, especially of Dactylorhiza incarnata. This year, I’ve finally visited this Baltic Sea island, in a quite warm and dry summer.

Such Dactylorhiza incarnata f. albiflora without any color hue have been quite rare – on my round trip by bike I’ve seen four plants. That translates into an estimated ratio of two or three per 1000 plants, which is quite the relation to be expected. Quite more often have been plants with a light yellow hue, although those could not always be addressed as the subspecies (or other taxonomic order) ochroleuca.

It was obvious that Dactylorhiza incarnata, possibly the orchid with the biggest population on Gotland, is occuring here in an marked color polymorphism – from white (very rare) to yellow (occasionally), light violet/pink (common) and the dark purple (common) flowers of the cruenta form which is sometimes viewed as a subspecies.

With Orchis mascula there have also been albiflora forms in the frequency to be expected from genetical mutations. In all those plants the pattern of purplish points in the flower lips has been preserved.

On a meadow near Oestergarn there was a beautiful white-flowered Gymnadenia conopsea among hundreds of plants..

Following a hint by Marco Klüber I also found an almost white-flowered Orchis spitzelii in a pine wood on the Northwestern coast. The color hue was still recognizable, the loss of pigments not as far reaching as here. But it’s still an indication that this orchid species also shows a genetical inclination to develop albiflora forms.

Albiflora couple in the valley of Kinzig

With Orchis mascula, the albiflora forms are not rare. But in many cases the pattern of violet points is preserved in the lips – even if the production of Anthocyanin is disturbed, the last reserves are obviously kept for this pattern. This year, a pair of Orchis mascula was flowering entirely white in the valley of Kinzig (in Hesse, Germany):

The leaves of these plants are unspotted, while the violet-flowered Orchis mascula often have intense spots.

Nearby, Orchis purpurea was beginning to flower. The third orchid species on this meadow in the “Schdänerer Weiberch”, as it is called in the Hesse idiom at the beginning of the path, is Himantoglossum hircinum. In May, the lizard orchid is just beginning to develop its inflorescence.

A bit further on the path, at the edge of a small forest, there was another albiflora form of Orchis mascula, also without any violet color in the flower, but with a marked green stigmatic lobe. The green hue is also preserved in the spur.

(with many thanks to Matthias Raschka for indicating me the location)

The dynamics of evolution on the Dactylorhiza meadow

Seven years after my first observations on a meadow in the valley of the small river Bieber in the northern region of the Spessart mountains I visit this special habitat again. The meadow with a wet trench in the middle is in full flowering. My estimation is that about 600 Dactylorhiza plants are flowering here: About 500 Dactylorhiza fuchsii, 50 already withered Dactylorhiza majalis and 50 hybrids Dactylorhiza fuchsii x majalis. Among the accompanying plants are Rhinanthus spec., Pedicularis palustris, Campanula patula and even a group of Arnica montana. Platanthera bifolia is just showing the first flowers.

Among the 500 Dactylorhiza fuchsii are about 400 plants with very bright flowers and a pattern of bright violet loops on the labellum. Furthermore, I count 22 albiflora forms with white flowers and non-spotted leafs. This is a rate of 4.4 per cent – much higher than you could expect if those were just spontaneous mutations. When I first visited this place on 20.6.2010 and 1.6.2012, there were less albiflora plants. Only about 80 of the 500 Dactylorhiza fuchsii have an intense violet colour. This meadow presumably has its own dynamics of evolution, developing increasingly bright forms of Dactylorhiza fuchsii.

There might be a relation with the learning experience of bees: With the earlier flowering Dactylorhiza majalis, many pollinators may have already made the experience that there is no nectar in the spur of violet orchid flowers. While developing brighter flowers, Dactylorhiza fuchsii might counteract this learning experience. Young honey bees still have to make this experience like this one on the flowers of the hybrid Dactylorhiza fuchsii x majalis:

Albiflora abundance on Sardinia

There are two forms of albiflora mutations with orchids:

the spontaneous growth of a white-flowered form as the consequence of a genetical defect in the process of creating anthocyanine pigments, traditionally called a freak of nature, Occurence: 1-5 among 1000 plants
populations of white-flowered mutations as the result of an evolutionary adaptation to environmental conditions, e.g. the concurrence of other violet-flowered food-deceptive orchids, occurrence: 10 to 500 among 1000 plants

I’ve found both forms on the Sarcidano plateau, a central region of Sardinia.

On lengthy hikes between Láconi, Ortuabis und Santa Sophia I’ve seen only one single albiflora form of Orchis mascula subsp. ichnusae, with the crimson marking of the flower labellum still preserved:

Before, I had already seen a single Orchis anthropophora without its typical flower colouring, in the forest of Domusnovas, on southern Sardinia:

Much more frequently are the white-flowered forms of Anacamptis morio subsp. longicornu in Sarcidano. Respectively one third of the overall several thousand plants in this region has the dark violet colouring, a bright violet (or rose) colouring or are white-flowered.

You can’t find this accumulation of albiflora forms in other regions on Sardinia which I’ve visited, neither at Domusnovas/Iglesias nor in the North or at Monte Albo. There, Anacamptis morio subsp. longicornu are consistently flowered in the regular violet. The albiflora forms of Sarcidano possibly have an evolutionary advantage. In this region there are also many Orchis mascula subsp. ichnusae giving pollinators as bees the learning experience that there is no nectar in the spur at flowers with this colour and form. In the other regions Orchis mascula subsp. ichnusae was less common or not present.

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):

white flowering in Engadine

Visiting this Eastern region of Switzerland, my special interest was focussed on Epipogium aphyllum, flowering in dark forests. “Aphyllum” refers to the lacking of any leafs – and so they don’t have any chlorophyll. Some plants also miss anthocyanins – the Swiss expert of the region, Joe Meier, sent me a a photo of a totally white flower found recently. He pointed out that this form could not only be addressed as albiflora, but also as albino – following the definition of a plant without any pigments. I’ve found a plant with reduced anthocyanin in its lip, while a rose hue is still slightly existent:

The trip to the region near the charming town Scuol also confirmed the slightyl increased tendency of Gymnadenia to develop albiflora forms. While there has been quite a lot of Gymnadenia conopsea with a marked purple colour, I also met a white-flowering plant:

Most of Gymnadenia odoratissima tend to a very bright purplish colour while retaining some visible hue of it. But on a mountain meadow there was also a plant without any anthocyanin in the flowers, even the column being yellowish-whitish:

Orchis olbiensis – Andalusian chromatics

Orchis olbiensis has a colourful and a light variety, as it is stated by Kretzschmar/Eccarius/Dietrich in “Die Orchideengattungen Anacamptis, Orchis, Neotinea” (Buergel 2007, p. 322). The light variety has flower colours between rose and almost white – with a colourful lip pattern contrasting to the light background. The white-flowered plant comprises almost half of the populations in Spain, the authors observed – quite in difference to the almost purplish flowers of Orchis olbiensis in France.

Five years after visiting Orchis olbiensis for the first time in Southern France, I had now the chance to study Orchis olbiensis in Southern Spain, in the province of Malaga. Though in mid-April I’ve been quite late for this species, I found two albiflora forms of Orchis olbiensis in the limestone formation of the Torcal, near the small town of Antequera. The greater plant had nine almost white flowers with the fine purplish dots still conserved. In this habitat there were also growing Anacamptis papilionacea, Ophrys scolopax and Orchis mascula subsp. laxifloraeformis.

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.

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.

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.

Albiflora forms of Dactylorhiza saccifera and cordigera

Though Dactylorhiza fuchsii is developing albiflora forms more often than other European orchids, especially in certain regions (Ireland, some German regions), there are no mentions of white-flowered Dactylorhiza saccifera. Both species are diploid and related with each other. Exploring the marsh areas of the Smolikas mountain in mid-June in Northern Greece, I’ve seen this splendid Dactylorhiza saccifera f. albiflora on wet grounds, in a height of 1200 m, embedded in Marsh Horsetails (Equisetum palustre) and accompanied by Dactylorhiza baumanniana and Neottia ovata.

In the same area there was also a white-flowered Gymnadenia conopsea with a slight purple hue.

Another highlight of the field trip to Northern Greece: three white-flowered Dactylorhiza cordigera on a clearing in the Vitsi mountain range near Kastoria. Those were surrounded by more than 1,000 cordigera plants with their characteristic deep purple colour.

The picture of albiflora forms of late flowering orchids in Northern Greece was completed by a Dactylorhiza incarnata f. albiflora near the village of Chrisi:

In the bog of white orchids

Most orchid species don’t like acid boglands – but there are two rare exceptions: One is geographically widely distributed from Belgium to Northwestern Germany and Scandinavia and is mostly addressed as Dactylorhiza sphagnicola. The other grows only in the Danish region of Thy: Just a few hundred meters behind the coastline of the North Sea there is a population of white-flowered orchids which have been described by Henrik Ærenlund Pedersen as Dactylorhiza majalis subsp. calcifugiens (in: Nordic Journal of Botany, 2004). In 2007, Sebastian Sczepanski and Karel Kreutz argued it would be more appropriate to regard these plants as a subspecies to Dactylorhiza sphagnicola – while Pedersen und Mikael Hedrén are viewing sphagnicola only as another subspecies of Dactylorhiza majalis. Apart from colour, the morphological differences of the single flowers of Dactylorhiza majalis subsp. majalis (left), calcifugiens (middle) and sphagnicola (right) are difficult to discern:
The spur of Dactylorhiza sphagnicola is a bit longer than that of D. majalis subsp. calcifugiens. And the leaves of the latter are spreaded in a broader angle than those of D. sphagnicola:

The single flowers don’t show any hue of purple, even the pollinaria lack Anthocyanin. There is rather some yellowish hue in the center of the flower, slightly reminding of Dactylorhiza incarnata subsp. ochroleuca. In contrast to other populations of albiflora forms, e.g. with Dactylorhiza fuchsii, there are no gradual differences in the loss of colour pigments – all the plants are consistent in the white colour of their flowers.

Visiting the region, I found calcifugiens at two places, one near the small fisher village of Lild Strand with only three plants, the other further to the south at a bog called Nissekaer with about 150 plants. Surrounded by dunes this place is a natural depression (danish: “kaer”) with a length of about 1500 and a width of about 250 meters:
Google Earth image of Nissekaer
In mid-June the orchids are just in the beginning of flowering. Most Dactylorhiza majalis subsp. calcifugiens are growing at the edges of the wet places, not in the midst of them as it is the case with Dactylorhiza sphagnicola in the Venn moors in Belgium. And the calcifugiens plants are quite smaller, reaching just a height of up to 31 cm. Neighbouring plants are Sphagnum palustre, Equisetum fluviatile; Eriophorum angustifolium, Menyanthes trifoliata, Vaccinium oxycoccus, Calluna vulgaris, Trientalis europaea and even Drosera rotundifolia – most of those plants are clear indicators of acid soil. Among the shrubs there is the dominant Myrica gale, which is used by the brewery of the near-by town Thisted.

Some calcifugiens plants show a broader labellum, indicating a possible hybrid influence of Dactylorhiza maculata – similar to the sphagnicola plants of the Venn region.

Among all the white-flowered orchids in the Nissekaer bogland I found two purple-flowered plants which might be a hybrid of Dactylorhiza majalis subsp. calcifugiens and Dactylorhiza maculata (left) and a Dactylorhiza maculata still in buds (right):

As a visiting and possibly pollinating insect of Dactylorhiza majalis subsp. calcifugiens there was a species of the genus Syrphida – as I’ve seen also with Dactylorhiza sphagnicola in the Venn moor (left)