Plant Life in the Scottish Highlands
The Bogs

Most visitors to the Highlands must have been struck by the huge areas of bogland to be found in almost every situation, whether in valley bottoms, on gently sloping hillsides, or on elevated plateaux.

Most of us must have been disagreeably aware of them when tramping over the mountain sides, and many the long detours one has been forced to make to avoid these treacherous areas of water, mud and moss.  All visitors must have also been struck by the sight of Highland crofters cutting peat sods for fuel along the drier edges of many a quaking bog.

To what is due this peat formation?  Why are such vast areas of mountain land covered by bogs?  The answer to these two questions is bound up in the climatic factors of rainfall and temperature.

In the warmer, well-drained soils, countless numbers of unseen organisms are ceaselessly toiling to break up plant and animals remains into substances such as ammonia and nitrates, chief among them being the soil bacteria.  The ammonia is oxidized into nitrites by a bacterium call Nitrosomonas, and these are then oxidized by another bacterium, Nitrobacter, into nitrates.  Thus all organic material disappears in the course of time, the products of its break-up enriching the soil.

The bacteria responsible for this can only do their valuable work in the presence of oxygen, and at a suitable temperature, hence they cannot work in soil which is waterlogged, as the water drives all the air out of the soil.

Now the Scottish Highlands are a region of very heavy rainfall which is distributed throughout the year.  Wherever natural drainage is blocked, the soil becomes waterlogged, with the result that flat, relatively low-lying plateaux, such an Rannoch Moor, the bottoms of valleys, the shores of lakes and gentle slopes become soaked with water which is often visible at the surface.  At the same time the average temperature over most of the area is rather low.

Conditions such as these are not conducive to the oxidizing bacteria, and so vegetable remains instead of being broken up endure in their fallen state.  They form acids which attack the mass of undecayed vegetation and blacken it, but it is not reduced to mineral salts, with the result that year after year the leaves and stems of heather, moss and fern add layer on layer to the waterlogged soil.

In time the pressure of the upper layers presses the lower layers into a hard compact mass which can be cut into blocks, and drying can be used as fuels.

After centuries have passed the pressure increases until the lower peat becomes a brown coal-like substance called lignite.  Such a layer buried under huge masses of soil and rocks will become real coal after the passage of thousands of years.

Peat, like a sponge, holds vast quantities of water and in course of time a deep peat bog may be formed.  This is an area of liquid plant remains covered by bog moss, but although the surface appears quite firm, it is a death-trap to the unwary as the drier surface layers cover a mass of liquid into which the poor unfortunate sinks without hope of succour.

Owing to the concentration of acid in the soil, the lack of oxygen and of mineral salts, peat is a very infertile soil, which cannot support trees and is shunned by most herbaceous plants.

Some plants, however, have become specialized to this habitat, as for example the insectivorous plants which depend for nitrates upon the insects they catch.  For this reason the Butterworts and Sundews are abundant in these areas.

Typical bog plants are the Grass of Parnassus (Parnassia palustris); the Bog Myrtle (Myrica Gale); The Cloudberry (Rubus Chamaemorus): the Marsh Cinquefoil (Potentilla palustris); the Bog Violet (Viola palustris); the Cranberry (Vaccinium Oxycoccus); the Bog Whortleberry (V. fuliginous); the Dwarf Birch (Betula nana); the Bog Asphodel (Narthecium ossifragum) and the Scottish Asphodel (Tofieldia palustris).  Several species of Sedge, conspicuous among these being the Cotton-grass, are abundant in the bog lands. 

Many plants show xerophytic adaptation due mainly to the exposed wind-swept situations, not, as formerly believed, to the acid soil.

Grass of Parnassus (Parnassia palustris)

This plant is a very beautiful one and is abundantly common in the Highlands, being found I bogs throughout the whole area and attaining a considerable altitude.  It flowers late in the year and one may often come across its chaste white flowers as late as October in the milder werst.

The Grass of Parnassus possesses a very short rootstock which is but slightly imbedded into the mosses and mud of the bogs it inhabits.  The leaves are all radical and are produced on long, up-curving stalks, which take them above the damp air immediately above the surface of the bog.  They are smooth and shining so that water vapour which condenses upon them will immediately run off.

From the midst of the leaves rises a slender flowerstalk, which attains nine inches to one foot in height and possesses a single sessile leaf which is produced half-way up the stem.  The stem is crowned by a single large, pure white flower, the petals of which run down towards the nectarines.

The flower possesses a tiny clayx of five small ovate sepals, whilst the five petals form a large saucer-shaped corolla which is very conspicuous.  More internally we find the five stamens, and beyond them five peculiar objects which are actually modified stamens.  They are flattened structures from which protrude several appendages which are for all the world like little golden-headed pins in a pin-cushion.  These appendages form a fence around the pistils, and the nectarines are found at the base upon their inner side.  In the centre of the bloom, we shall find the ovary with its four stigmas.

The reason for these modified stamens is rather a mystery.  The Grass of Parnassus is pollinated by flies, which may often be seen licking the golden shining knobs as if they expected nectar to be secreted, in which hope they are disappointed.  It may be that they perform the function of false nectarines to attract the flies, or on the other hand they may act as a fence which forces the flies to approach the real nectarines in a certain fashion which makes sure that transported pollen if left upon the stigmas.

The stamens move in over the stigmas on by one until all the pollen has been shed, when they return to their original position.  The stigmas then mature and become receptive.

Flies are the chief visitors, visiting the flowers both for pollen and nectar.

The Bog Myrtle (Myrica Gale)

Few must be the number of hikers and walkers in the Highlands who do know the Bog Myrtle, for apart from its widespread distribution and its abundance, the sweet fragrant odour which issues from every bog makes the plant obvious before it is actually seen. For, no matter where we may walk in the Highlands, except at great elevations, we must meet with the bog myrtle and its odour is a very part of the Highland scene.  It is one of those odour which form the complex smell of the Highlands, that nostalgia-giving perfume composed of bog myrtle and peat, of pine and heather, that tang of sea air and the cool breeze of the mountains which assails one as soon as one alights from the train, and warns the traveller that he has once again returned to the Highlands.  That perfume which one can smell long after one has returned to the city, as if it would pull us back to the purple moors and brown mountain sides, to the black pines and the silver lochs.

The Bog Myrtle itself is not a very attractive plant.  It has no beautiful flowers or beauty of form and yet for all that Nature has endowed it with this glorious perfume contained in certain specialized cells in the leaves and stems.

It is an inhabitant of wet, boggy places and its roots delve down into the mosses and peat to find a suitable anchorage.  It attains two to three feet in height although at higher altitudes it is considerably smaller.

The brown, slender, woody branches are covered with lanceolate rounded leaflets which are usually rather downy upon the under surface and contain numerous resinous cells.  The downy under surface is, of course, nature’s means of protecting the stomata from excessive condensation from their boggy surroundings. These leaves are shed in the autumn.

The flowers of the Bog Myrtle are very unattractive, consisting of small, brown, stalkless catkins which are formed along the extremity of the branches often before the leaves have commenced to grow.  They are dioeciously, i.e. the female flowers are produced on one plant and the male flowers upon another, as in the case of the willow.

The male catkins, which are longer than the females, are composed of many brown, imbricated scales, and have no petals or sepals.  Six to eight stamens are produced in each scale, the anthers being almost stalkless.

The female catkins consist of two ovaries within each scale, at the base of which the vestiges of a perianth may be seen.  They are crowned by two stigmas produced upon long styles.

The catkins produce no nectar and, from the length of the styles, it is obvious that they are fertilized by wind-borne pollen.  This explains why the flowers bloom early in the year before the leaves are fully formed.

After fertilization the female catkins form a small resinous, nut-like fruit containing one seed.  The resinous coat protects the seed in its wet surrounding until such time as the warmer weather makes germination possible.  If the seed falls into water it is well protected until such time as it drifts upon a bank of soil and can commence an independent existence.

The Cloudberry (Rubus Chamaemorus)

This member of the Rubus genus is quite a different plant from the others already described (see Chapter XII).  It is to be found fairly frequently in mountain bogs and may attain considerable altitudes, and I have found it on Cairngorm at 3,500 feet.

It produces a large creeping rootstock in comparison with which the above ground portion of the plant seems ridiculously small.  This is another example of how mountain plants have become prominent geophytes.

Above ground are produced short stems which seldom attain six inches in height and are often much less.  I have gathered plants in the Cairngorm at 3,500 feet in which the whole plant did not exceed two inches in height.

The leaves of this species are not divided and are large and rounded, or often kidney-shaped with a white cottony down on the under surface which protects the stomata from the damp vapors continually arising from their boggy surroundings.

The flowers are large and conspicuous and are produced singly on a terminal peduncle.  Their pure white colour and spreading petals make them easily seen and they are visited for their honey by bees.

After flowering, a beautiful orange-colored fruit is formed, and as it is very finely flavored it is much sought after for jams and jellies.

Its name is Cloudberry is probably derived from the fact that the species is found in those regions where clouds cover the sky for many days of the year.

The Marsh Cinquefoil (Potentilla palustris)

It is a fairly common plant in many parts of the Highlands, being found in peaty bogs, on the edges of lakes and in marshy places in many of the lower coastal regions, and in the valleys and glens.

It is a peculiar looking plant as it often assumes a bluish-purple hue, the stems, glowers, and even leaves often sharing this colour.

Its perennial rootstock sends up weak stems which are rather creeping at the base, where they often send out adventitious rootlets.  They become more erect towards the extremity, but usually sprawl across the surrounding plants and mosses.

The leaves are produced on long stalks and consist of five almost equal, oblong leaflets arranged like the fingers of a hand and are either quite smooth above with soft hairs below, or are hairy on both surfaces.  As with the meadow sweet this is to guard against condensation.

The flower which terminate long stalks are rather strange, being of a dull purplish colour often approaching a brownish tinge.  Like the Water Avens they possess a double calyx which is usually tinged with purple, and is longer than the corolla.  The yellow anthers are conspicuous against the dull purple background of the petals are the main attraction to insects.  They possess much nectar and, as in the case of the Water Avens, large bees are probably the chief benefactors.

Bog Violet (Viola palustris)

It is difficult to pick out the most beautiful species in this family of lovely plants.  No one can say that the gloriously perfume Sweet Violet is more beautiful than the yell Mountain Violet with its large show flowers, or than the Dog Violet whose numbers may tint the woodland banks with blue.  I am sure, however, that most people will agree that the demurely attractive Bog Violet can hold its own with any member of the family.

If one visit’s the bogs in May, one may be rewarded by the sight of tufts of long stalked, heart-shaped, shiny leaves from the midst of which arises a slender stalk crowned by a delicate, lilac-blue flower.  This is the Bog Violet.

It possesses a long, slender, creeping rhizome which may extend for a considerable distance through the soft peat and bog mosses, and at intervals gives off slender white roots which push down into the peat, whilst tufts of leaves are given off into the air.

The leaves have beautiful crenate edges and are completely smooth and shiny.

The flower has the structure of the typical violet, but is very small, the lilac petals being delicately marked with dark veins, whilst the spur is very short.  The flowers are visited by small bees.

The plants also produce cleistogamous flowers in the same way as the Wood Sorrel, and these ensure that seed is set if the showy flowers are not visited by insects, as must often happen in bad season.

THE BOG VACCINIUMS

A very typical bog plant is the Cranberry (V. Oxyoccus), which may be found, if one is lucky , in some Scottish peat-bogs.  I say ‘if one is lucky’ because this plant is rather local in distribution, and is not to be found in every peat-bog that one may chance upon.

It is very difficult from the other members of the Heath Family that we have dealt with, but shows its affinity to the whortleberries by its very similar red fruit.

The Cranberry possesses very slender, wiry stems which creep over the surface of the bog, climbing over the mosses and other small plant and often forming matted carpets.  The stems send out roots at intervals.

The leaves are evergreen, very small and egg-shaped, and their xerophytes natures is shown by the fact that their edges are rolled over as in the case of the Trailing Azalea and the Heaths.  Thus most of the stomata on the under surface are enclosed between the rolled-in surfaces.  The under surface is grayish-blue in colour from a waxy covering which prevents water soaking the surface and blocking the stomata.  This s a very necessary precaution for a plant creeping over a wet surface.

The flowers are solitary at the summit of a long, slender, drooping peduncle.  Unlike the other whortleberries the corolla is not campanulate or vase-shaped, but instead is deeply divided into four bright red segments which spread outwards and are often recurved, with the result that the stamens are fully exposed.  They are visited by small bees, and flies which pollinate them. 

The flowers are followed by bright red berries which are greedily devoured by grouse and blackcock which are instrumental in distributing the seeds.

The Bog Whortleberry (V. uliginosum) is a very different plant, but much more common and it may be found at considerable altitudes in the Highlands.

It resembles the Whortleberry (V. Myrtillus) (see Chapter XI) very much, but may be distinguished from that species by the fact that its branches are almost cylindrical and not angular, it is also much smaller, more woody and more branched, the leaves being smaller, but thin and deciduous.  The flowers are very similar, whilst the fruit cannot be distinguished by size or colour.

Dwarf Birch (Betula nana)

This is another shrubby plant which, like the Bog Myrtle, prefers bogs for its habitat.  It is a very different plant from its relative, the Silver Birch, and rarely attains the stature of a tree, and although luxuriant specimens twenty feet high may be sometimes found, it does not usually exceed three to five feet.

The plant is at once known by its leaves, which are different from those of any other British shrub.  They are very short, rarely more than half an inch long, almost circular in form with beautifully crenated margins, dark green in colour and completely smooth and shiny.

The catkins are similar to those of the Silver Birch, but are very small, the males ones being oblong in form, whilst the females are thinner and only about a quarter of an inch in length.

They are wind pollinated and the seeds are winged as in the case of the Silver Birch.

Bog Asphodel (Narthecium ossifragum) 

This plant is very abundant throughout the Highland area and is often the dominant member of the vegetation.  Before the flowers are in bloom, the plants appear like those of rushes; however, the Bog Asphodel is a member of the Lily Family.

The rootstock is tough and woody, and buried in the mud and peat, giving rise to a stiff, erect stem about six inches in height, the lower part of which is covered by the remains of the dead leaves of other season.

The actual leaves are narrow, flattened and grass-like in form, and are arranged in two rows on each side of the stem, in much the same way as those of the Iris.  They are glabrous, deep green and shiny, and when the plants are growing in large colonies, the resemblance to some species of sedge is very marked.

The flowers are produced at the summit of the stem to form a dense spike.  The perianth is constructed of six members, each of which is lanceolate, sharply pointed, widely spreading, green on the outer surface and bright yellow on the inner one, hence when the flowers are fully out the spikes are very conspicuous.

The flowers resemble those of the Jointed Rush or Toad Rush, and for this reason some botanists have placed this plant in the Rush Family.

The six stamens are beautiful objects, their filaments being covered by a thick, white wool.  The ovary is very pointed and terminated by a single stigma.  The flowers are visited by flies, which are probably the chief pollinating agents.

After fertilization the flowers are followed by long, orange-read capsules.  Hundreds of plants, each with its spike of orange-red fruit, make a delightful splash of colour in the autumn, when most bright hues have faded from the bog lands 

Scottish Mountain Asphodel (Tofieldia palustris)

The plant resembles the Bog Asphodel, but is much smaller in all its parts and much less common.  The leaves are in two rows, and are sword-shaped and very narrow.

The flowers, which are greenish-yellow in colour, are produced in dense, terminal spikes and are very similar in structure to those of the preceding.

It is usually found in elevated stations and is rarely found below the 500-feet contour.

Bog Orchid (Malaxis paludosa)

The Highland bogs have also their own orchid, a tiny plant to found in sphagnum-bogs, here and there throughout the whole area.  It is a very difficult plant to discover, because the flowers are green in colour and hence lose themselves against the bright green background of mosses.

If we carefully extract the plant from its mossy bed, we shall find that it consists of a tiny bulb suspended among the lower moss stems and anchored by several fine roots given off from the base of the bulb.  These toots ramify among the mosses and do not enter the soil.  It thus resembles those tropical, epiphytic orchids which perch upon the branches of trees and have no contact with the soil.

From the summit of the bulb arise three or four oval, concave leaves.  If we examine them we shall find that the upper part is fringed with minute, greenish tubercles.  These are actually bulbils and from some of them, if we look closely, we may see the rudiments of two or three leaves.  The tubercles are freed by the decay of the leaf margin and they drop off to form new plants.  This is yet another example of vegetative reproduction.

The erect flower-stalk may be four inches in height in luxuriant specimens, but is often no more than two inches high.  It is terminated by a slender raceme of very small, greenish-yellow flowers.

If we examine a single flower under a lens, we shall see that there are three narrow, outer, perianth segments (sepals), two pointing upwards and downwards.  There are three petals, two very minute and spreading laterally, and the third forming the lip (labellum).  The latter is remarkable because instead of being pendent it is erect and forms a hood over the stigmas and anthers.

The flowers are pollinated as in the case of the other British orchids (see Chapter XX).  In this plant, however, each anther cell contains a pair of pollinia which are in the form of very think leaves of waxy pollen, the grains of which never separate.

In spite of their small size and inconspicuous colour, the flowers are highly attractive to insects and most of the flowers in the spike are usually cross-pollinated.

This little plant is interesting as it is the only British representative of the Malaxeae tribe of orchids, which includes a large number of magnificent tropical species.

Marsh St. John’s-wort (Hypericum elodes)

To find this lovely little plant, we must confine our search to the spongy bog lands of Argyll and the Hebrides, for it belongs to the Atlantic flora and is not found far away from the influence of that ocean.

I have found it only once in a mossy bog in Argyll.  I shall never be in any doubt as to its identity if I chance on it again, for it has a strong disagreeable, resinous odour which is difficult to remove from the hands.  It is also remarkable in being covered with white woolly hairs, although inhabiting wet saturated places.

Its stem creeps for about one foot over the surface of the bog and roots at the nodes.  It is clothed with a thick mantle of white hairs as are both sides of the round, opposite leaves, which clasp the stem by their bases.  The hairs help to keep the leaf surfaces free from water, which would otherwise clog the stomata and impede gaseous exchanges.  Hairy leaves are met with in other bog and marsh plants such as the Hairy Willow-herb and the Water Mint.

The stems turn upwards at their extremities and produce a few-flowered, leafless cyme of pale, yellow flowers.  The sepals are edged by a fringe of glandular teeth which effectually bars further progress to creeping insects such as ants.

The flowers are visited by bees and flies for their pollen, no nectar being secreted.

Marsh Penny-wort (Hydrocotyle vulgaris)

This creeping perennial is to be found throughout the Highlands and is fairly common in the lower marshes and bogs and is rarely found above 1,500 feet.

Usually our first acquaintance with this plant is a mass of round, shiny leaves covering the mosses and other lowly herbage of the bog.  The stems are only apparent if we pluck a handful of moss, when we hall find that each leaf is attached to a long, weak stalk, which in turn arises from a slender, creeping, white stem.  The latter creeps in all directions among the mosses and gives off bunches of fine roots at the nodes.  The plant is perfectly specialized to its habitat and its delicate stems and roots are kept moist and protected from drought and cold by the soft blanket of mosses.

The leaves are quite round, with beautifully crenate margins, and are peculiar in being attached to the stalk at their middle point; such leaves are known as peltate.

From the axils of the leaves arise short, leafless stalks which are terminated by a single tiny head of minute flowers, with sometimes one or two whorls lower down.

It will come as a great surprise to my readers to know that this plant belongs to the Umbelliferous Family.  The tiny flowers remain concealed in the mosses and are self-fertilized, although small creeping insect may accidentally cross-fertilize them in crawling over the blooms.

BOGLANDS SEDGES

Let us visit any large stretch of bogland in summer; one can pick out any corner of the Highlands one chooses.  My choice would be a lovely stretch of green moss and running water near the shores of Loch Coruisk in Skye, in the very shadow of the Black Coolins.  Others may prefer that lonely and yet strangely beautiful area, where Rannoch Moor runs up to meet the Black Mountains; here you can pick and choose, as there are bogs everywhere.  No matter what place you choose, you will be certain of finding most of the plants described here.

Having arrived at your bog, you will probably be struck by a host of nodding silky white tassels, shining in the sun and swaying gracefully in the wind.  This lovely sight is caused by the fruiting spikes of the Cotton Grass, the seeds of which are surrounded by very long, silky hairs.

Cotton Grass (Eriophorum vaginatum)

We have two species in Britain, the Hare’s tail Cotton Grass (Eriophorum vaginatum) and the Common Cotton Grass (E. plystachion).

If we dig up a plant of the Hare’s-tail Cotton Grass from the soft peat, we shall find that it possesses a long whitish rhizome, giving off many tufts of roots and at intervals leaves and stems.

The leaves are cylindrical in form, the edges being rolled up on each other.  This is, of course, a xerophytes adaptation, and thus when temperatures are low and strong winds are sweeping the bogs, the plants run no risk of excessive transpiration.

The stems are terminated by a dense spike of long, silky hairs.  If we had visited the bog in May, we should have found that the silky tufts were not in evidence, instead each stem would have been found to be terminated by a yellowish spike of flowers, similar to those of a sedge except for the fact that both pistils and stamens occur in the same flowers.

If we had dissected out a flower, we should have found that it was composed of olive-green bracts surrounding three stamens on long, slender filaments, and a tiny ovoid ovary surmounted by a long, trifid stigma.  Around each ovary would have been seen several short bristles, and it is these which lengthen after fertilization to form the silky tufts so conspicuous in summer.

Whilst searching among the plants of Cotton Grass, we may notice many stouter looking plants bearing several head of hairs instead of a solitary one.  This is the Common Cotton Grass.  It is very similar to the preceding, but the spikes of flowers are produced in an umbel which is overtopped by one or two long green pointed bracts.

When in seed the many dense tufts of hairs, which may exceed one and a half inches in length, form a very beautiful object indeed.

As we examine the many different inhabitants of our particular bog, we may notice masses of stiff, rush-like stems terminated by handsome, dark, shining brown, dense heads of flowers.  This is the Bog-rush (Schoenus nigricans) in which the flowers are similar to those of the sedge, but are not unisexual.  Each stem is terminated by two or three brownish bracts which have long, stiff points and overtop the spikes.  The leaves are small and not very conspicuous, forming dense tufts at the base of the stem.

Bunches of fine, wiry stems about nine inches high and producing a terminal spike of pale, almost white, spike lets betray the presence of the White Beak-sedge (Rhynchospora alba), which produces one or two small, lateral spikes well below the terminal one, whilst a long fine, greenish, pointed bract overtops each spike.

We may also be attracted by another plant producing a head of very dark brown, almost black, spike lets.  Its leaves are small and cylindrical, whilst the flowers are partially concealed by large, brownish bracts.  This the Narrow-leaved Blysmus (Blysmus rufus), which is very abundant in the Scottish Highlands. 

Besides these particular species of the Sedge Family, we may find many different species of the real Sedges (Carex). We have over seventy species in Britain, many of them being bogland plants and many of them are extremely abundant.  Their general characteristics have already been described in the chapter on the Mountain Pastures, and it would be out of place in this book to attempt to describe the numerous species, but those who are interested and have plenty of patience, and would like to discover the names of the different varieties, must refer to a British flora.

A very interesting and beautiful collection may be made of these plants, and although at first the various species appear very similar, it will be found that each one has an individuality of its own. Their search and discovery will add much interest to many wearisome tramps across the desolate spots of the Scottish mountains.

I may add there that to those of you who wish to discover all there is to know about Highland botany and plants, and who posses a microscope and plenty of patience, there is a large field of discovery open among the mosses and their close relatives the liverworts.  These lowly plants make up a large part of the mountain flora and many are peculiar to the Highlands.

Many interesting ferns, club mosses and horsetails may be found on the Scottish mountains, so that there is plenty of scope for those who would study our own mountain plant life.  The search for these plants will take you into many a spot which would not be visited under other circumstances, whilst the arrangement and study of your collections will give you untold joy and happiness during the long winter evenings when all Nature is sleeping.