The Bog Orchid

Since I was a little kid I've always preferred the tiny, unique, and stubby creatures. The ones you've gotta really look at before you see that they're not tiny; the world is just very big. These little guys are often incredibly complex, with unique adaptations for surviving on such a different scale to what we normally take note of, forming a weird and wonderful world all around us. No need to travel great distances to far off lands to see exotic-looking, almost alien-like organisms.

I remember going out on little adventures years ago in hopes of finding colourful tiger beetles in the Forest of Bowland, and elusive brook lampreys in local streams. I would collect mosses from walls and try to make tiny gardens with them, using shards of pottery and some small ferns to create what looked like a mossy section of woodland floor overgrowing the remains of an ancient civilization.

Back then I just had the Collins Complete Guide to British Wildlife by Paul Sterry, which I though really was the complete guide (oh how wrong I was), and I would look through this book which inspired me to try and find a variety of different species that I thought were cool. Of these, I remember one miniscule species I never could find, no matter how many times I explored peat bogs in the Lake District while hiking with Grandma, and eventually forgot about looking for until I stumbled across one while squeezing through a hole in a deer fence on North Morar: the bog orchid.

Orchids are monocotomous plants in an order known as the asparagoid lilies. Within this order, they make up the plant family 'Orchidaceae', of which the common English word 'orchid' is a shortened form. This word literally comes from the Ancient greek 'órkhis' (ὄρχις), meaning 'testicle' in reference to the shape of the twin tubers of some species in the Orchis genus, after which the whole family of plants was named. They are an immensely diverse and widespread group of flowers, often with asymmetrical and very specifically adapted flowers making them very recognisable among flowering plants. However, they are somewhat simplified in the public eye, where they are largely recognised as fancy and exotic houseplants such as the commonly sold Phalaenopsis genus of orchids, or as rare and unusual rainforest species kept in botanical gardens for display.

In reality, there are around fifty-seven orchid species found in the UK (excluding allopolyploid hybrids), with a variety of flower colours, shapes, sizes, habitats, and rarities, and of these I've seen twenty-four (26 including allopolyploid hybrids). These all have three petal-like sepals (in most plants, sepals are green and form protection and support behind the petals, especially as part of the bud before it opens), two 'normal' petals, and a specialised petal which forms what is known as a labellum. Labella, meaning 'lip', are specialised petals that usually stand out among the others, often being larger, an irregular shape, and with a different colour or pattern. The labellum is also often fused with the gynostemium (a fusion of both the male and female reproductive parts of the flower, often called the column) to form a specialised structure which attracts insects and adds pollen to them before they leave for pollination. This pollen of orchids is often not dust-like as in other flowers, coating pollinators as they brush by, but rather may be held within sticky, waxy masses know as pollinia, which are attached to pollinating insects and are highly efficient, but often very specialised, relying on just one or a few pollinator species per orchid species. These pollinators aren't even always rewarded with nectar, or anything at all, for their pollination services, as some orchid species (using their colour, fragrance, and especially the shape of their labellum) trick particular insects into thinking they are females of the same species, prompting them to try and mate with the flower and get pollen stuck to them in the process.

These plants are beautiful and fascinating, and renowned worldwide by botanists for their unique and specific adaptations and morphologies. It is well worth keeping an eye out for them around the UK and further afield when you're out and about.

On the 7th of July 2021 I was staying with my family in Mallaig and decided to head for a hike into North Morar. The plan was to head up to Sgurr Bhuidhe, which basically translates to rocky yellow peak from Scottish Gaelic, getting there by turning up the hillside via Carn Mhic a' Ghille-chaim just off from the path to Loch Eireagoraidh. This requires crossing a deer fence between Beinn nan Caorach and the stream An Leth-allt ('allt' is a gaelic word for stream). The area was beautiful, with open peat bogs, craggy peaks, waterlily-filled lochans, and waterfalls along the stream. While the deer-fence was tall, this one had a small gap part way down it in a corner, where other people had clearly come through along their way to Loch Eireagoraidh. I pushed my bag through this gap, and then squeezed through myself, coming out on the other side crouched over a small wet flush of water trickling through the bog. It was filled with great sundews (Drosera anglica) and other cool species, but I soon spotted something that I instantly recognised from my childhood nature book; a bog orchid.

This plant was tiny, the UK's smallest orchid. It grows to a maximum of 15cm in height, but is usually less than 8cm tall, with flowers that are about 4mm by 4mm and are so thin that they are translucent, with large leaf cells providing a texture that makes the flower seem overall almost crystalline and gem-like.

Bog orchid (Hammarbya paludosa), also sometimes known as bog adder's-mouth orchid, is the sole member of the Hammarbya genus, after Otto Kuntze reclassified it in 1891 and named the genus after Carl Linnaeus' summer residence in Hammarby, Sweden (Carl Linnaeus came up with the first iteration of the modern species classification and binomial naming system, and described bog orchids during his time as Ophrys paludosa). The paludosa part has stuck through the nomenclature change, and for good reason: it comes from the Latin noun 'palūs' - swamp, marsh, bog, fen - aptly describing this orchids' natural habitat. Bog orchids grow in bogs where there is a slow flow of water over the surface, preferring the acidic conditions of peat bogs, though more alkaline conditions are also tolerated. On North Morar I found it on bare peat where a shallow layer of water is trickling between blades of sedges and grasses, and I found it in the same habitat on the other side of Beinn nan Caorach when I returned to the area in 2022, though it apparently will also grow among Sphagnum mosses. Throughout the UK they are widespread, but often just in local patches, being overall quite rare outside of north-western Scotland, although they are also found across boggy areas in the rest of the upper northern hemisphere too.

Living in such harsh conditions, with waterlogged and acidic soils reducing potential for nutrient uptake, bog orchids have adapted to be compact and also have no true roots, instead relying on a symbiotic relationship with fungi in its rhizome to obtain nutrients (the fungi gets nutrients from the ground more efficiently than plants can, and the plant provides products from photosynthesis in return, and a place for the fungi to live. With no true roots to anchor it to the ground, the small stature of this species is absolutely necessary, or its delicate inflorescence of flowers will be knocked over in the breeze. Instead, it shelters beneath the other bog plants, hiding its subtle beauty from view.

And what a beauty it is! This species grows from a little pseudobulb, with a few tiny basal leaves and a yellow-green stem rising up through the centre to hold up the flowers, which are also greenish, with a shiny translucence that I love, reminding me of my favourite moss species - shining hookeria (Hookeria luscens). Under a light they look even cooler, appearing a shiny bright lime colour which isn't as visible in the other photos, though in person this species' lime green does make it stand out brightly from the nearby bog flora when it isn't shrouded by it.

The beautiful flowers of bog orchids are unusual even among the famously bizarre flowers of the orchid family. You see, most orchids go through a process known as resupination during the development of their flowers. This comes from the Latin 'resupinus', meaning 'bent back and facing upwards', relating to the adjective 'resupine', describing something that is facing upward or is upside-down. Resupination in orchid flowers is the process by which they twist 180-degrees as they develop. The labellum is the top petal in the bud, but the bud twists around as it opens such that the labellum hangs down in the open flower as an open lip providing a landing place for pollinators, and exposing its insect-attracting features to the sun more as it faces upwards and site below the surrounding other petals and sepals which decorate it. This provides the common resupinate orchid flower structure with a sepal pointing straight up, two sepals being diagonally down on either side, the normal petals in front of the sepals being diagonally up or horizontal on either side, and the labellum sticking forward and down at the front.

Bog orchid flowers aren't like this. They have a sepal pointing straight down, two sepals pointing diagonally up on either side, the normal petals being horizontal on either side, and a small labellum at the front pointing forwards and upwards. This places it among the non-resupinate orchids, which look upside-down, and of which there are fewer. Bog orchid flowers aren't in this orientation in the way you'd expect. The orientation suggests that bog orchids have lost the trait of twisting the flower during development, perhaps because it wasn't particularly useful since its labellum isn't as pivotal to pollinator attraction, and its pollinators - tiny flies - are light enough to not really require a less vertical landing platform. However, the flowers of bog orchids actually twist a full 360-degrees during development to end up in the same orientation that they started in, as was noted as far back as 1862 by Charles Darwin himself in his book 'Fertilisation of Orchids'. I don't think anyone quite knows what selective pressure lead to this growth form evolving, or quite what it is for, but it looks to me like the important reproductive part of the flower now has a little rain cover. In the following photos I contrast it against the more typical flower form of bee orchid (Ophrys apifera), though this species' diagonally up petals are very reduced and the sepals are more horizontal:

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So yeah. This was a short and quick piece that I felt like doing because I enjoyed learning about this species and was so excited to find it back in 2021. It definitely seems like a find worth sharing again.