Contents Page 4 Introduction 5-6 Chapter 1; Large common liverworts
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| 4. Polytrichum and other large Mosses.
Anyone who finds a Sphagnum habitat, and is looking at mosses generally, will certainly find many other kinds. There are so many, the beginner will soon feel overwhelmed. It pays to be selective. However, most mosses and liverworts can easily be kept alive for a time in the way described in Chapter 2. Those from drier places are best set aside in this way, at least for now. However some others, especially those of wet acid heathland, can be grown in the same way as Sphagnum. Among the largest and most obvious mosses are Polytrichum. P. commune often occurs among Sphagnum, and can be grown in the same way. It is the largest British species, and can make dark green tussocks up to a foot tall. On drier heathland, two other species are common. They are large compared to most mosses, but smaller than P. commune. Both have a hair point on the end of each leaf. In P. piliferum, less than an inch tall, it is white, and the tufts may have a silvery appearance. In P. juniperinum, a slightly larger plant, the hair point is reddish. In acid woodlands a fourth species is common. It may reach three or four inches in height. In drier parts of Britain it needs shade. It is P. formosum. The leaves usually have a trace of red at the tips, but no hair point. A good hand lens is helpful, since it makes it easy to see another clear-cut difference; P. commune and P. formosum can look very similar. They have flat or slightly incurved leaves, like those of a tiny Yucca. The leaf tips of P. piliferum and P. juniperinum, which tend to grow in drier places, have their margins tightly inrolled, giving the leaf a spear like tip. All four species can be grown like Sphagnum, in plastic pots of peat, stood in trays of rainwater. In a greenhouse, they do not enjoy hot sunshine. Some shade is desirable in summer, and they may grow better in fairly high humidity. However, unlike Sphagna, they can survive desiccation, especially P. piliferum. Any intelligent plantsman, on first finding P. formosum and P. piliferum, will see that they do not grow in waterlogged places. These two can be left dry, in plastic or clay pots of peat and/or lime-free builder's sand, in part shade or full sun, and allowed to dry out during the summer. If watered well from September till May, they will grow quite fast in spring and autumn. However all these four species are quite sensitive to "lime" formation on the shoots and leaves. This "lime" can become the major problem for moss growers, and it is worth looking at it in some detail. Mosses are fundamentally different from flowering plants and ferns. They mostly have little or no vascular tissue, that is, internal tissue designed to carry water. That is why most mosses are small. Water can only slowly diffuse up through the plant, from the soil. This works well enough for smaller mosses, say up to about a quarter of an inch tall. Larger mosses usually absorb water directly through the whole plant surface. This is why they need spraying from above. Watering the soil in which they grow does little or no good. Some larger mosses draw up water from the soil, not though their roots and stems, but externally. They soak it up like blotting paper. This is how Sphagnum remains moist. However, rooted plants can absorb the water and nutrients they need selectively, and in general can leave in the soil any dissolved substance they do not want. Mosses cannot select in this way. If the soil contains dissolved substances, they are drawn up along with the water, and as it evaporates, they make a deposit on the leaves and stem. It is perhaps significant that the mosses and liverworts which have been most widely grown in the past are those with strong rhizoid (root) systems, which are most like flowering plants, and least troubled by lime. To grow most of the others, the grower must usually find some way of preventing these deposits from forming. One obvious way is to keep the plants moist or enclosed, so that there is less evaporation, and therefore less deposits are formed. Another almost opposite approach is to keep the soil so dry that there is never any free water. A third approach is to use totally lime and nutrient-free soil - pure peat perhaps - and water only with distilled water. This does not work for lime-loving plants, and anyway does not completely eliminate these deposits. All these methods help, but none are entirely right for Polytrichum. It is usually sensible to imitate the conditions in which plants grow naturally. There is one important factor in the environment which very few plant growers or botanists seem to take account of. It is the impact of falling rain. Take some plants - any plants - from indoors, or from a greenhouse, and put them outside for a week during rainy weather. The dirtier, dustier and more neglected, the more encrusted with lime or infested with insect pests they may be, the better. As rain washes them clean, the difference is obvious. Mosses can be grown under cover, but most will only flourish if the cleansing and leaching action of rain is simulated by thorough and reasonably frequent spraying. A large garden spray is not just a convenience, but the most essential single piece of equipment. Polytrichums have strong rhizoids, but also draw up water along capillary channels, up the stems, around the leaf bases and up the leaves themselves. Even if you bring home a tuft on its original soil, if it is left waterlogged in a dry place, as on a windowsill or in a greenhouse, it will soon begin to spoil as deposits build up on the leaf tips. The remedy is simple. It is, to wash them off with a spray of rainwater. Once this problem is mastered, these are easy plants to maintain. My surviving cultures are over 20 years old. They may need replanting every year or two onto fresh peat, as the old shoots begin to die. They will grow all through the year, except perhaps in the very hottest or coldest months, making their strongest growth in spring. On fresh peat, new shoots soon appear, thrusting up from underground stolons. In one respect I have failed with Polytrichums. Male and female organs are on separate plants, and both are striking. The capsules are among the largest of any moss, but only one of my cultures has produced them in recent years. Other British Polytrichums include P. strictum. It grows among Sphagnum, like P. commune, but in wet hilly and mountainous areas. It has shorter leaves and narrower stems, the lower parts of which are covered with a white felted growth of tomentum, which conducts water. It may be grown like P. commune or Sphagnum. P. longisetum is less common. It looks like P. formosum, but with wider translucent margins to the leaves. Microscopic examination may be needed to confirm its identity. P. alpinum is a rather nondescript plant, superficially like P. formosum. It is occasional in mountainous places, among steep or even overhanging rocks, or on acid soil in rock clefts. P. sexangulare is a highly specialised plant of snow patches - hollows on the highest Scottish mountains, which are covered with snow for over 9 months a year. It will not survive without special treatment. Another species, formerly included in Polytrichum, but now placed in another genus, is Pogonatum urnigerum. It is rare in the South, but frequent on wet soil banks and by streams in hilly areas. It is a typical Polytrichum shape, but young shoots are of a striking pale glaucous blue-green colour. A related but smaller plant, Oligotrichum hercynicum, with blunt incurved bright green leaves, is frequent on acid soil banks in the West and North, becoming more luxuriant and abundant higher on mountains, and reaching the highest Scottish summits. These four can be grown waterlogged, but on acid mineral soil rather than peat. I have found washed sand, as supplied by D.I. Y. and builders' merchants, to be acceptable, as a layer over peat. None like hot summer sunshine, which will kill them in a greenhouse. They are less easy to keep. Chapter 13 discusses the problem of growing these cold-loving plants. Pogonatum aloides, formerly called a Polytrichum, is mentioned later, and has a quite different habitat. Polytrichums are very unusual among mosses in having thick leaves. Most mosses have delicate leaves a single cell thick. The very common Atrichum undulatum is related to Polytrichum, and like Polytrichum, has a broad band along the middle of the leaf, which is reinforced and thickened by ridges made of cells projecting from the top of the nerve (lamellae). However the margins of the leaves are thin and translucent. The leaves also have teeth along the edges, visible through a lens, and a characteristic wavy (undulate) appearance. It could be confused with the even larger and more delicate Mnium undulatum which also has undulate but less pointed leaves, and creeping stems. It grows on damp sheltered soil. These two can be grown on soil, rather than peat, and do best in moderate or high humidity, as in a propagator. There are several frequent species of Mnium. The commonest is Mnium hornum, described in chapter 6, which has upright stems. Most, like M. affine, have arching stems and wide delicate leaves, but less undulate. All grow fast and easily on damp soil, in a cool shady place. In a related genus is Rhizomnium punctatum. It is about a half-inch tall, or more. Its large round leaves with a strong border are very distinctive. It grows best on rotten logs in acid swamps, and can tolerate deep shade. A lens will show the brown filamentous growth around the base of the stems (protonema) by which it spreads, and from which new shoots arise. On damp or wet rotten wood in a plastic pot, and in high humidity, it spreads fast but rather unpredictably, making most of its new shoots in spring. Mnium undulatum can grow on chalk or lime-rich soil. Apart from that, these plants need acid or neutral soil. Lime or hard tap water is likely to kill them. If you collect them to grow, collect also a small bag of soil from the place where you have found them. A quite small amount will do. They can be put into a pot of peat with about a dessert spoonful of soil on top. A careful look at acid ground will reveal many other mosses and leafy liverworts, mostly smaller than any mentioned in this chapter. Some of them are described in chapter 6. 5. Garden Mosses This chapter is not about growing mosses in your garden. It is about finding them. It is also, in part, about attitudes. I once met two young Japanese ladies, visiting England as part of their training to become qualified tourist guides in their own country. They were eager to further their training by administering and explaining a Japanese Tea Ceremony to their uncomprehending English acquaintances. More rewarding, for me anyway, than the strange green liquid we tasted together, was a glance in a Book of Useful Phrases they had brought with them from Japan. Among other things, it contained this quaint dialogue; TOURIST. "Why is there so much moss on the stones in a Japanese Garden?" GUIDE."Because it is the object of a Japanese gardener to encourage the things of nature as much as possible." Considerable sums of money are spent each year in persuading British gardeners to bash, burn, and poison as much of the 'things of nature' as possible, including the mosses on our lawns, on our paths, and even on our walls and trees. When greater sums of money can be made out of persuading British people to grow mosses rather than kill them, then it will surely become a mass pastime, promoted by the so-called "Gardening Industry". Meanwhile, it is only remote and mysterious people like the Japanese, who encourage mosses on their rockeries and monuments, or even devote gardens to an appreciation of their quiet beauty. The Japanese have philosophical ideas about landscapes, and about simplicity and repose, which are expressed in their traditional gardens. Those ideas are quite different from those expressed in British gardening advertisements, and in so many British gardens, crammed with lurid mass-produced bedding plants, gardens from which everything wild, everything unpredictable or mysterious or complicated is supposed to be excluded, and in which everything is supposed to be under total control - except perhaps the weather. To people who promote this kind of gardening, mosses are surely the ultimate irrelevance One of the most interesting exercises for any gardener, if he or she can defy these attitudes, is to observe things, rather than do something to them. It needs no tools, no money, and very little energy - just, perhaps, a pencil and notebook. Very few gardeners ever make a deliberate survey of what is actually in their own garden - be it a survey of insects ("pests"), of birds' nests, or of wild plants ("weeds"). I recommend making a survey of your garden mosses. I made such a survey in Reading in 1963, on the week I moved into our house there. Among the squashed and abandoned childrens' toys, the builder's rubble, and the heaps of rusty bedsprings, were only 20 species of wild plants, including fruit trees, and various scraps of grass which had survived trampling by a family of children. Yet there were as many as 14 kinds of moss. The first lesson to be learned from such an exercise is that really thorough searching of a small area, even an unpromising one, may reveal more kinds of mosses than a superficial look in an apparently far more attractive place. Any reasonably civilised garden should have about a dozen kinds, though some may need intensive searching with a lens to discover. A lawn should hold a few, a piece of cement, or a brick or stone wall should have 3 or 4, even in the most polluted town, and a soil or cement path at least half a dozen more. In this chapter, I will concentrate on those which are most likely to be found on soil. If you are reading this book, you may want to gather some, identify them, and try growing them in a flower pot. As a gardener, you will not want to merely observe your plants. You will want to control them. And you will soon discover - as I did - the maddening fact that many mosses, even from your own garden, seem resistant to any kind of control or cultivation. If you try to grow those same mosses in a flowerpot instead of killing them, you can expect many disappointments. In a frame, a greenhouse, or even outside, although they may enjoy the same climate, the same position and the same soil, many will refuse to flourish or even survive, until you have begun to understand their cultural needs. I will give descriptions of a few of the commonest garden mosses, and a few ideas for growing them. It is the ideal way to learn, for whenever a culture fails you can replace it, and check the conditions in the spot you took it from. Most gardens are unlikely to contain any liverworts except Lunularia and perhaps, in a wet corner, Marchantia. I have already mentioned these. More rarely, shady lawns may have a leafy liverwort, Lophocolea bicuspidata, described in the next chapter. Looking at the mosses, you will soon see the distinction between two main groups. There are those with creeping or branching stems (pleurocarps) and those with close-packed upright stems arising directly from the soil (acrocarps). I will describe first some pleurocarps, since the common garden ones are relatively large. On a lawn, unless it is very shaded, or the soil is very acid, the obvious mosses will be creeping pleurocarps. Brachythecium rutabulum is the commonest large species. It is one of our commonest British mosses. It is equally likely on paths or garden beds. Also common, even on the humblest lawn or the dullest housing estate, is Eurhynchium praelongum. This has a quite different appearance. Its pinnately branched stems may be distinguished with a lens from those of other similar mosses. This will show its distinctive feature, that the stem leaves are much wider than the leaves on the branches. A piece of turf has a history, no less than an ancient tree or a medieval hedgerow. Older lawns - if they have not been wrecked with chemicals - may contain orchids or other small flowering plants of interest. Mosses may be part of that history. A former professor of botany near Reading owned a magnificent lawn on chalk soil, containing mosses characteristic of an almost vanished habitat - the flower-studded chalk turf which once covered much of the Chilterns - mosses which are now rare in the surrounding countryside. Botany students visited, to admire and to study them. Few homeowners can boast of such a thing, but many older lawns contain Rhytidiadelphus squarrosus, a very characteristic plant, with leaves strongly recurved. Some lawns, especially on wetter clay soil, may have Calliergon cuspidatum. The individual leaves of this, though blunt and lacking a nerve, are so tightly rolled together at the shoot tips as to make a point which feels quite sharp when touched. Shady lawns and paths may have Eurhynchium confertum, like E. praelongum but irregularly branched, with weaker straggling stems.. On acid lawns, heathland mosses may grow, including Polytrichums, which look very dark green against the grass, and under trees, woodland species may occur, such a Mniums and Atrichum undulatum. or these plants, the choice of soil is obviously no problem. A little of the soil on which they were growing is sure to be suitable. When choosing a soil, it is worth remembering that most mosses can only exploit the surface layer. There is no point in giving them more than a half-inch or so of soil, at most. If they are in a flower pot, it is often convenient to fill the pot with peat or fibre, and to put a sprinkling of the appropriate soil on top of that. One of the few botanists who has published an account of his efforts to grow mosses was Professor Paul Richards. In "Mosses; A King Penguin Book" in 1950, he wrote; "I have found that most mosses grow well either in earthenware pans, glazed on the inside, or in ordinary porous flower pots or pans stood in an inch or two of water. The pot or pan should normally be covered with a sheet of glass, as even if it is standing in water, the moss may dry out in warm or dry weather.. A situation for the moss garden should be chosen which is protected from direct sunlight, at least from April to September. An ordinary unheated greenhouse is suitable, provided there is shade from the summer sun and precautions are taken against overheating." In subsequent articles, he described similar ways of growing large liverworts. My experience is similar, but differs in two important respects. There are so many unpredictable factors that it would be rash to give precise guidance on how best to grow the plants I have just mentioned. I will only say that with the exception of Calliergon cuspidatum, these mosses above do not like being waterlogged. I have grown them all in clay pots (well drained), on a shaded shelf of a greenhouse. I did not have the benefit of a cool shaded site for the collection in Reading, as this book makes plain. The species mentioned above were sprayed frequently, but were allowed to dry out for long periods in warm summer weather, when the temperature in the greenhouse, despite shading, was too high for healthy growth. In cooler autumn and spring weather they grew fast, filling a pot within a few months. At these times they could be covered with polythene sheeting, which kept them moist for days on end. Cultures may deteriorate after a year or two, or become overcrowded. When they do, they are best replanted onto fresh soil. Once you have a system that works, and start looking for new but similar mosses from further afield, it becomes important to notice what kind of soil they are growing on. The distinction between acid and alkaline soils becomes obvious, as one learns to recognise the plants, and especially the mosses, associated with each kind of soil. The texture of the soil may also be important. Mosses of sandy soil will usually not flourish on clay, or vice-versa. When collecting mosses to grow on any scale, it is a good idea to keep plants from the same locality together, and to bring back also a small plastic bag of soil from the site. A small spoonful of this soil, sprinkled on top of peat or fibre, will be quite sufficient for most of them. In general, the smaller the plant, the more important it is to choose the right soil or substrate for it. However the important thing at first is to establish a place, and find a way of planting and watering, which works for a few of the commoner ones. Anyone who can grow just the few creeping species mentioned already could in theory build up a sizeable collection, and one of considerable scientific interest. Even just in lowland Britain, there are over 30 species of Brachythecium, Eurhynchium and related genera alone, which can be grown in similar ways. Here are usually more species of acrocarps in the average garden, though they are smaller. The exact species depend very much on the nature of the soil. Many will be difficult for a beginner to identify. Bright yellow-green plants with a white hair on the tip of a broad leaf are probably. It is usually on brickwork, cement or walls, and is described and drawn in chapter 7, but is so common that it may turn up on soil or paths as well. Plants of a similar colour, but without the hair point, are usually Didymodons or the closely related Barbulas. These are a large group, with about ten reasonably common species. Some are not at all easy to identify. Several are likely in gardens, especially on paths. B. unguiculata has a rather solid leaf with a sharp tip. B. convoluta is usually paler, lemon-green, and also with a slightly wavy leaf. D. fallax has short narrow leaves, twisted and incurved when dry. D. insulanus has longer narrow leaves, irregularly twisted. These all like a lime-rich soil, well drained, (use clay pots, not plastic), and plenty of light. They only grow well if kept in high humidity, and thoroughly sprayed with water, but are well adapted to cope with long periods of drought. I have long treated them as seasonal growers, on a rather warm greenhouse shelf with diffuse sunshine, and watered freely between October and April, leaving them dry and dormant in summer. In later years most have grown well on lime-rich "mounted" cultures, as described in Chapter 8. Few gardens are without a Bryum or two and few towns or suburbs without five or ten of the fifty known British species. Plants of this genus can be the most difficult of all to identify. On soil, especially in cracks of paths and pavements, is the silvery B. argenteum, (see page 25), an unmistakable plant. Its shoots, like tiny silvery fir cones, are a beautiful sight under a good lens. Often growing with it, but of a darker green, is B. bicolor. This tends to disappear in summer, at least in the drier parts of Britain. Two common and very similar species on soil in gardens and fields, in Berkshire and elsewhere, are B. rubens and B. subapiculatum. Like many other plants of this genus, thee last three have tiny bulbils or tubers, visible through a x10, or better, a x20 lens. The position of the bulbils may make it possible to distinguish these three; B. bicolor sometimes has no bulbils, sometimes a lot. They are green, and borne among the leaves near the top of the stem. There are actually several very similar species, mostly rather rare. B. rubens has a few reddish bulbils in the leaf axils at the bottom of the stem. B. subapiculatum has tubers on its underground rhizoids. They are often bright red, and can then be spotted with a good lens, despite being buried in the soil. I will not delve further into the mysteries of this genus, except to say that even in central Reading, at least ten species of Bryum seemed to occur, mostly on walls and tarmac. Some defied identification. Fissidens are most distinctive mosses, with their leaves folded flat, forming on each stem a small stiff fernlike shape. A garden on clay soil may well contain F. bryoides, or the larger and slightly paler F. taxifolius. A strong lens or microscope will show the pale border of narrow cells on the leaf of F. bryoides. Gardeners who laugh at the idea of growing mosses often say “I have some in my greenhouse!" This is a pretty sure thing, for anyone who keeps their pot plants wet enough is soon going to get Leptobryum pyriforme, with its delicate tufts of fine wavy leaves, and probably also Funaria hygrometrica, a budlike plant with a large lopsided spore capsule. Both fruit freely, though Leptobryum is a rather delicate plant, and rarely grows luxuriantly in the open air. They are the commonest "weed" mosses in greenhouses, but rarely persist for long in one place, especially if this happens to be a flower pot where a deliberate attempt is being made to grow them! Two other tiny curiosities are likely on heavy loam or clay soils. Both are short lived annuals, dying away in summer, but leaving spores for next year. They are Tortula truncata and Tortula acaulon. They freely produce their characteristic fruits. Tortula acaulon fruits are on such a short stem as to be almost hidden among the leaves. All these acrocarps have a strong rhizoid system, and can draw up water very effectively from the soil. They grow fast and well, and can tolerate waterlogging, drought, some sunshine, except in high summer, moderate shade, or any combination of these conditions. The trouble is that they are so small, and that things happen so fast, especially with the short-lived annual species, that within a couple of weeks, cultures are sure to contain a mixture of several species, and the one you started with (or thought you did) has died, or is replaced by something different. If you have taken a lot of trouble to identify the original plant, this is most annoying. They are, after all, ephemerals, so I suppose a plant that disappears in culture is behaving as it would in habitat! It helps, to start fresh cultures fairly frequently, every six months or so, and as carefully as possible, on fresh soil, using tweezers and a magnifying glass to pick out the individual shoots you want. The pots can be wrapped in Clingfilm for a week or two to keep them moist, and to stop unwanted spores and fragments contaminating them. I nowadays keep ephemerals on "mounted" cultures, on a thin layer of soil on pieces of polystyrene tile. This gives far better control over what is actually being grown, and I have managed to keep track of them far better in recent years. Even so, you may not get reliable results, especially with the Tortulas mentioned above. Indeed, serious long-term collections of some of these small ephemeral plants may be best kept in test-tube cultures. I give a few ideas on how to make "mounted" and test-tube cultures later. I make no attempt to list other likely garden mosses, even in footnotes. I have given some idea of the variety of mosses you may find in even a quite ordinary garden. If you manage to name even half of them at first, it will be no small achievement, and to attempt to grow them, especially the smaller or more nondescript ones, involves considerable skill. Yet it is not wasted effort, for the same techniques can be applied to hundreds of other species, and to many other very small plants. Anyone who starts a similar project with mosses from outside Europe may encounter dozens of inconspicuous species which have never been grown by anyone before. Some of them are likely to be new to the country concerned, or even new to science. Many people, including some who have asked me about it, approach moss growing from a different direction. They are less concerned with acquiring, naming or growing lots of species, and more interested in creating mossy landscapes, or encouraging mosses in their gardens generally. The Japanese moss garden, with its use of rocks and gravel, is the only relevant tradition I know, but is only one of many possibilities. Mosses rarely compete with larger plants. They grow on rocks, walls or trees, where there is little or no soil, and little competition. They only make conspicuous growth in places where flowering plants are stunted or absent. To try growing mosses in the fertile soil of a garden bed is usually as futile as trying to grow parsnips on top of a bare wall. Where the soil is too acid, too deeply shaded, too low in nutrients, or too thin and dry for normal garden plants to survive, there will mosses flourish. Likewise, in severe climates, on the highest Scottish mountains, or in high Arctic tundras where little else can grow, there also mosses may predominate. More rarely, moss-dominated places can be found, such as old lead or copper mines, chemical waste sites or zinc-contaminated ground under electricity pylons, where the soil is too poisoned to support normal vegetation. Few gardeners would wish to create such habitats, even where it might be possible to do so. Nevertheless, if you want mosses to play a noticeable part in any garden, a suitable habitat must be created. The most likely habitats will contain little or no soil. There is no need to import pieces of rock, for cement and tarmac make excellent habitats. When fresh, they are hostile, but after a few years' weathering, they are sure to become covered with mosses unless something prevents their growth. Some will be garden mosses already described, but, especially if exposed to sunshine, many will be walltop mosses, described in a later chapter. My own garden in Reading was full of old bricks. They were used to make paths, borders, and retaining walls to some garden beds. They were slightly porous and alkaline, and they supported a rich growth of mosses. The retaining walls especially offered some scope for introducing mosses deliberately, including a few which do not naturally grow in Reading. So did a rather exposed north-facing brick wall at the front of the house, on top of which several unlikely species became established, after being glued onto the bare bricks. I used a waterproof spirit-based glue (uhu) or, in later years, a silicone-based flexible sealing compound. There is usually not the slightest chance of success in sticking mosses on walls in this way, without a good understanding of which species are likely to survive in a particular place. Sloping surfaces, but not usually vertical ones which receive little rain, are best for mosses. It would not be sensible to gather any mosses except the very commonest ones described in this chapter, for use in such plantings. Better far to create or conserve the garden habitat, and then see what grows in it. Herbicides have their uses, since they kill flowering plants but usually leave mosses and liverworts unaffected. One could use them, for instance, to create a grass-free moss lawn, which would of course be a great improvement, needing no mowing! It would also be safer, since wet grass, is often slippery after rain. There is an unusual garden in the Cotswolds whose owner once weeded out all herbs, leaving only carpets of native mosses. However he did not introduce new species, nor know which ones were growing there. Many mosses need higher humidity than is likely in a garden. A moss-covered log for instance, moved from woodland, is likely to lose much of its cover within months. Where water runs from a gutter or overflow, especially into a shaded corner, there may be a small wet area where Marchantia, Conocephalum, or perhaps some mosses may flourish better than elsewhere. An acquaintance has used Marchantia as ground cover at the wet margins of a garden pond. Many mosses and liverworts of wet places could be grown thus, so long as the distinction between acid, neutral and basic conditions is understood. A garden fountain splashing onto rocks can also encourage waterside mosses to grow. A bank or slope of peat blocks (or peat-substitute blocks) is a good habitat for acid-loving mosses, and a pond filled with wet acid peat might well support Sphagna and associated plants, including mosses. There are other natural habitats which might be recreated or imitated on a small scale, even in a small garden, and which might support a few characteristic species of mosses or hepatics. A sunny wall top, for instance, with a thin layer of soil on top, can provide a home for some very characteristic mosses. There are lots of other possibilities which I have never tried, and never seen done convincingly by anyone else. Only someone who has learnt to appreciate wild plants, including mosses, and who has gained some understanding of their habitats, is likely to achieve anything, or even to see what those possibilities might be. However, the small size of so many mosses makes it difficult and uncertain to keep track of introductions, however carefully they may be made and observed. In general, I think one is likely to learn more about mosses, and to achieve more, by studying those which are already in a garden, and by trying to grow them under controlled conditions, than by introducing new species to the garden itself. |