In Pursuit of the Wild Lady's Slipper Orchid
Visited June 10th, 2014 with the Lakeland Horticulture Society
The Kallgatburg nature reserve is unique as its location straddles two different forms of bedrock; pure limestone that drains off quickly creating dry land and marlstone which is a lime rich mud that contains clay and silt that creates marshy areas. Often different flora can be observed on either side of the reserves well marked 2.7 km nature trail. The popularity of Kallgatburg though is the lady's slipper orchids discovered at the Kallgatburg Nature Reserve in 1950.
The reclusive wild lady's slipper orchid (Cypripedium calceolus L.) has become the main focus of many day trips to Southern Gotland for botanists and flower lovers in early June when the orchid is in full bloom. Tuesday morning our travel guide George Feather, was determined that he was going to find this wild orchid in bloom as he missed it's bloom time on the trip in 2007. He found a note in the comment book at the sign-board at the car park dated the 8th, two days earlier, that the orchid was in bloom, but no indication of the location or distance was given. Regardless, the quest was on.
It was a short walk through forest area and then pastureland where the nature trail began. The Dropwort (Filipendula vulgaris) and the long-stalked cranesbill (Geranium columbianum) are tucked among blodrot (Potentilla erecta) in the meadow grass.
Hiding in the grass was a solitary bright yellow "pea" flower (Fabaceae family), nicknamed the Winged pea or the Yellow Dragon's teeth named by Linnaeus Tetragonolobus maritimus. This hardy perennial herb is mainly found on the damp coastal meadow grounds. The species name maritimus,comes from the Latin mare (sea) meaning growing by the sea. The winged pea's preference are the marshy grounds of meadows, swamps and stagnant pools with brackish soil. It is native to Sweden, found only along the south-east coastal border of the mainland and on the islands of Gotland and Öland.
The common fleabane (Pulicaria dysenterica) a perennial herb of the Asteraceae family, was used for the treatment of dysentery (hence its Latin species name), takes to a wide range of soil types from meadows to marshes. Its common name is from the past tradition of using the plant in the house to keep flies and fleas at bay when hung in dried bunches above the doorway or burnt on the fire.
Beside the pathway a variety of plants were found with the differences in the terrain and bedrock. In marshy areas long narrow wooden planks were laid down for walking. It had been a dry spring so the boggy areas were dry and mud boots were not needed. The group navigated stiles with wooden ladders over electric deer fences cautiously.
Along the edge of the shady woodland trail I found clumps of the lily of the valley (Convallaria majalis) a plant that my grandmother had in her garden and my mother had in the back yard of our home in Geneva, Illinois. No attention as far as care was paid to the unassuming plot of green foliage that thrived; reliable every spring with tiny white bell flowers with a vanilla honey scent.
Lily of the valley favors woodlands that are on sandy, acidic soil or limestone woods as found at Kallgatburg. All parts of the plant are poisonous. It spreads by sending out new shoots from its creeping rootstock but care should be taken not to trample the foliage as that will kill the rhizome. Perhaps my mother's inconspicuous green leaved carpet of the lily survived for years in a lawn where five children and a dog played by being tucked into a shady corner of the yard and ignored.
The family Orchidaceae is one of the largest families of flowering plants with numbers at twenty two to twenty six thousand species in the family. Orchids do have a complicated classification system. When Carl Linnaeus gave a binomial name to each 62 orchid species in Species Plantarum published in 1753, it was a useful system that was beneficial, increasing the knowledge of orchids. Botanist have not always agreed though on how different species should be categorized and numerous changes have been to genera and species since Linnaeus first wrote of orchids in Genera Plantarum in 1737. Characteristic of the genus Dactylorhiza are the orchids with two to five underground flattened and finger-like lobed tubers. One tuber stores food to carry the plant through winters and the plant grows out of the second tube. Previously these orchids were classified under Orchis,which now are considered the orchids with two rounded or ellipsoid tubers.
Gotland orchids are found in various habitats such as wet meadow lands or land that is not grazed heavily which is easier access for public viewing. Other orchids are choosier then others (ex. lady's slipper) which makes them more difficult to find. In common though is the calcareous soil that the orchids prefer, making the Islands of Gotland and Öland a destination for the student of orchids with approximately 33 out of Sweden's 40 plus species to be found on Gotland. The orchid season begins in early Mid-May and lasts until the end of August. Our visit to Kallgatburg in June coincided with the peak of the season to see a variety of European orchids in bloom.
Hybrids are often found within the same family on Gotland making identification difficult, especially the genus Dactylorhiza which has a number of species and subspecies and any two species can by hybridized. Carl Linnaeus originally name the heath-spotted orchid Orchis maculata in 1753 in his Species Plantarum. Currently named Dactylorhiza maculata, this tiny orchid, white with purple flecks, has spikes which can have up to 50 flowers. The heath-spotted orchid and the common-spotted orchid are sometimes considered two different species, are very prone to hybridization and distinguishing between the two (as with many other orchids) can be problematic.
Lesser Butterfly Orchids (Plantathera bifolia) bloom June to July with delicate creamy white to greenish flowers on a cylindrical spike that can have as few as 5 to 25 flowers that are highly scented at dusk to collect moths. It is found in damp grounds near bogs or deciduous woodlands and scrub on calcareous soil.
George provided assistance to me with plant identification on the islands, especially the orchids which can require close scrutiny and an expertise in botany to name correctly. George determined that this orchid was the lesser rather than the greater butterfly orchid by the alignment of the yellow pollen anther sacs. In the lesser they are parallel, lie closer together then the greater orchid and do not converge. In the greater orchid the anther sacs are widely separated and converge upward to form almost an inverted horseshoe. George pointed out that "small groups of intense botanists can spend hours debating the identification of minute plants."
Along the edge of the sheltered woodland path where there was adequate open canopy for needed sunlight to form it's beautiful oval pure white flowers with an orange-yellow lip,were orchids that Linnaeus named Serapias grandiflora in System Naturae published1767. Now this narrow-leaved woodland helleborine is assigned the name Cephalanthera longifolia.
The narrow-leaved helleborine is a long lived perennial woodland plant that has specific requirements to flower; light but shelter, well drained calcareous soil, and pollinating insects. When conditions for the plant are not favorable, it can survive by remaining in a vegetative non flowering state.
There are as many as 15 flowers on the top of its stem that are pollinated by small solitary bees even though the plants of this genus do not produce nectar or collectable pollen to attract pollinating insects. Deceitful pollination attracts the bees (Batesian mimicry) with this orchid exhibiting a stunning floral display that resembles other nearby nectar and/or pollinating plants. This deceit allows for mistaken but necessary pollination.
Reproduction is by seed only with the plant having a large number of seeds per pod to compensate for poor seed establishment. There is a symbiotic relationship between C. longifolia seeds and fungi that are present in the soil. The seeds have an association with ectomycorrhizal fungi (particularly those from the family of Thelephoraceae or the mushrooms known as the “leatherly earthfans.”) of neighboring trees ,which release a compound that stimulates germination. Without the presence of these fungi, the seeds of the C. longifolia will not germinate. Then there is a small range of fungi that are required to stimulate development. The orchids also obtain some of their nutrients from the fungi. Since not all trees have the required fungi, the orchid may be limited to sites where there are trees that have the fungi species required. After germination it takes many years of favorable conditions for the narrow-leaved helleborine to reach maturity; a maturity achieved by deceitful beauty.
The early purple orchid (Orchis mascula (L) also uses deceit to obtain pollination. The orchid has a nectar spur but contains no nectar or pollen for the pollinators. By blooming in early spring-summer it is able to dupe the inexperienced newborn bumblebees that are looking for nutrient plants with the most impressive flowers. The orchid's root system is formed from two tubers and in the past, these roots/tubers, which are rich in a complex carbohydrate, were used to make a flour called salep. Salep became a popular drink in the Ottoman Empire, then spread to Germany and England before the popularity of tea and coffee. The ancient Romans made drinks from the orchid tubers that they considered to have aphrodisiac properties.
The pyramial orchid Linnaeus named Orchis pyramidalis (1759) is now name Anacamptis pyramidalis (L.) is another example of orchids having a symbiotic relationship with mycorrhizal fungus to provide essential nutrients to the plant. The orchids seeds do not contain nutrients (lack of endosperm) to produce leaves and flowers so the seed relies on mycorrhizal fungus in the soil to produce the nourishment. This underground fungus-root relationship can take several years to develop before the plant sends up leaves and flowers. In the wild it does has an advantage over other orchids since its seeds have a longer viability then many of the others.
After an hour walk on the nature trail the majority of the group decided to return to the car park. It was George, Dorothy, Ann, Barry and Elli who accomplished the quest to find the large group of elusive lady's slipper orchid (Cypripedium calceolus) in prolific bloom with purple-brown flowers, twisted petals and large deep yellow lips, located in a small area of scrub land slightly outside the nature reserve (by George's directions) 1 km north-east of the northern edge.
Carl Linnaeus assigned the formal name Cypripedium in his Species Plantarum in 1753. Besides Europe, the lady's slipper orchid can be found in temperate eastern Asia, south to the Himalayas and North America. It has been over collected in several countries, endangering its existence. The flowers were so popular with collectors in England's Victorian Age that only one plant remained in that country. The plant was protected by a Cypripedium Committee and after several years when the plant retained its vigor and began to bloom again, the flowers were hand pollinated and the resulting seeds were sent to Kew for eventual reintroduction of the orchid back into its native habitat.
The Lady's slipper orchid has an unusual allure to obtain pollination since it does not secrete nectar for a pollinator to eat on. The flower has a mass of sticky pollen on the end of two stamens which attracts insects towards the yellow labellum of the flower that is pouch-like and deeply concave. The appearance of the flower attracts many kinds of insects towards the yellow labellum (the lower petal or lip of an orchid). Large insects, such as bumblebees, notice that there is no nectar and leave the same way they came in through the large gap in the labellum, pollinating the plant. The flower is pollinated by small burrowing bees which fall inside the slippery sack that is inclined inward, and land on the labellum. When the bee finds that it can not get out the way it came in, it crawls into a tight corridor between the two branched columns and the labellum. As it leaves the sticky mass of pollen attaches itself to the insect's back. The secret attraction is in the fragrance of the lady's slipper orchid which is partly the same as the burrowing bee's pheromones, which the flower secretes. Then the soft hair covering the sac releases the scent of the insect as it tries to leave. Studies have shown that the lady's slipper orchid has adapted to pollinators in its different habitats and there are differences in its fragrances.
All orchids are a protected species. At the Kallgatburg Nature Reserve there is a reverence for the lady's-slipper and care by the orchid “hunters”not to pick or damage the orchid blooms (or any other plants at the reserve); only photos will be taken away in cameras.
With the quest successful, it was a late lunch for the remaining group at the picnic tables by the car park. Our afternoon destination would be a different terrain; the limestone sea stacks at the Digerhuvud Nature Reserve on the northern Island of Fårö.
Photos of lady's slipper's orchid – by Dorothy Feather
All other photos by Deborah McMillin
References
http://www.kew.org/science-conservation
Kloth, Jens-Henrik and Lovén, Ulf, Field Guide to Outdoor Gotland, Natural History and Wildlife
Plantlife International – The Wild Plant Conservatory Charity – Narrow-leaved helleborine
Nature Gate http://www.luontoportti.com/suomi/en/
Raven, Sarah, Wildflowers, Bloomsburg, London
Woodlands.co.uk
http://www.greentours.co.uk/Wildlife-At-Leisure/GOTLAND/ Has an extensive list of the flowers on Gotland under 2011 trip report and a descriptive report of their botanical adventures on Gotland.