Mosses
 
Mosses are formally classed in the taxonomic division Bryophyta which is slightly confusing because the common term "bryophytes" also includes liverworts and hornworts. There are about 12,000 described species globally, and 763 in Britain and Ireland.  For our size, we have an exceptionally diverse moss flora, probably because we are a cool, temperate and soggy set of offshore islands.
 
Mosses are well represented in a number of garden habitats, especially in lawns where they are not always considered welcome. The BUGS project1. identified 64 species from 61 domestic gardens in Sheffield, of which 10 were found in lawns.  One species Kindbergia praelonga was present in nearly all lawns, while many others only appeared once or twice. As well as lawns, garden mosses are found in rotting wood, on garden furniture, walls and roofs, and growing on damp soil.  There is much scope for keen amateurs to add a lot to our knowledge of garden moss flora, especially since the species you find will differ a lot depending on soil conditions, and how far north or west you are.  In general, moss floras are most diverse in the north and west of these islands, and on acidic soils.
 
Types of moss
 
We can divide moss into two basic groups, the upright or acrocarpous mosses, and the sprawling pleurocarpous mosses. For identification, you need to look at the tiny leaves with a lens.  Are they serrated like a knife around the edge or some of it; what shape are they and do they have a central nerve or not – sometimes there is one for a little way, sometimes more than one, and in some mosses these nerves extend out at the leaf end, sometimes into a whispy hair point. These can be coiled, reflexed or grey when dry. It helps identification to note where you found your sample - was it on wood, concrete, stone or soil, was it in grass or some other garden feature?
 
The common names of mosses are not traditional, have been invented recently, generally reflecting the mosses' appearance to help remember them. The scientific names are tongue-twisters, but great fun.  Try saying the Latin names as if they are poetry – some sound really lovely. 
 
 
Acrocarpous mosses
 
These mosses have just a single stem with the leaves arranged up it, this may fork or have a few short branches, but basically the habit is vertical growth, as opposed to the branching and sprawling pleurocarpus mosses below. They all bear the sporophyte capsules from the tip of the stem.
 
 
 
References - see also Bryophytes page
 
1.  Smith, R.M, Thompson, K. Warren, P.H. and Gaston, K.J. (2010) Urban domestic gardens (XIII): Composition of the bryophyte and lichen floras, and determinants of species richness. Biological Conservation 143:873–882
 
2. Garden Organic Defra delays again on peat ban 
 
Page written by Penny Anderson, compiled by Steve Head
Common feather-moss Kindbergia praelonga
 
This is a more regularly branched, weakly scrambling pleurocarpous moss with a roughly triangular outline. It is distinctive if you look closely with a lens in that the branch leaves are much smaller than those on the stems, which are triangular-shaped but with a long, fine elongated tip which often turns outwards. These leaves are about 1.5mm long, so you need to look carefully with a hand lens. The nerve goes to the end of the branch leaf.
 
This neat little common moss sprawls on banks, in lawns, on the ground under trees or on their trunks and on logs.
 
 
 
 
 
 
Grey-cushioned grimmia Grimmia pulvinata  
 
The compact, often hemispherical cushions of this upright, acrocarpous moss are often hoary-grey as the long hair-points dry out. Look for it on roofs, tops of walls or on any stonework where it can be very common. The leaves on the single stem are oblong, but long and fairly narrow, with a nerve from bottom to top extending into a long silvery hair-point that may equal the leaf length, when dry these crinkle up. This feature and its neat rounded overall colony form is responsible for another common name "hedgehog moss".  
 
There are usually oval capsules on long, curved setae (stems) which tend to bury the capsule back into the cushion while it is young. This is a very distinctive diagnostic feature. 
Bonfire-moss Funaria hygrometrica 
 
This really does live up to its name as it colonises old bonfire sites readily as well as bare soil elsewhere. It is a common acrocarpous species being a little upright moss which forms loose carpets on the ground. It has egg-shaped leaves, 2-4mm long and an abundance of asymmetrical, yellowish to orange-brown capsules with a lovely little delicate ‘hood’ with an extended beak like a pixie hat.   
Wall screw-moss Tortula muralis
 
This is easy to identify as it grows in neat little cushions less than 1cm tall, usually on walls, concrete, roof tiles or stones, mostly in the open, but can tolerate some shade. The leaf’s nerve extends as a conspicuous, long, silvery hair-like projections from the end of the leaves which make the cushion look hoary grey when dry. You will need a magnifying glass to see the leaves which are tongue-shaped 2-3.5mm long, and twist and curl when dry, but spread out from each other when moist. The cushion is usually also marked by 1-2cm long purple setae (stems) with erect narrow cylindrical capsules at the top. 
 
This is one of the commonest mosses you can find on walls and tiles.
Capillary thread-moss  Bryum capillare
 
This is another compact acrocarpous moss that grows in small tufts or patches 1-2cm tall. It is very common on soils, in grassland, on trees or logs, fences, walls, roofs or rocks everywhere. Dry plants typically show corkscrew-like shoots, with the leaves spirally twisted around the stem. The broad leaves are only 2-5mm long and are widest about their half-way point – but you will need a magnifying glass to see these clearly. Unlike the wall screw-moss, the capillary thread-moss has capsules that are drooping but borne on reddish seta up to 3cm tall. 
Silver-moss  Bryum argenteum
 
This little upright moss is easily recognised owing to its pale-green or almost white colouring in compact tufts or patches which look shiny and silver grey when dry. The shoots tend to be crowded, small – usually less than 1cm, and the leaves are rounded and concave giving the shoots a smooth cylindrical appearance, whether wet or dry. If you look closely at a leaf, you will see the nerve ends well below the tip and may have a silvery tip. Little pendulous capsules about 1.5mm long grow on a short seta in autumn or spring. This little moss grows on disturbed habitats which are usually dry and low in nutrients, so look for it on poor soils, by paths, in the cracks between paving stones, on walls, buildings, roof, concrete and tarmac.
White-tipped bristle-moss Orthotrichum diaphanum
 
Another little upright moss, this one has white leaf tips which are diagnostic. It grows in little tufts of narrow, upright shoots up to 1cm tall, usually with abundant capsules. The leaves are 2.5-4mm long and the capsules, which are tucked into the leaves rather than on long seta, are covered in a hairless light green cap when fresh but are brown and furrowed slightly when old and dry. The leaves are held more or less straight and spread out when moist.
 
This moss is common and widespread on trees and shrubs, especially willows and elder which have nutrient-enriched bark, but it also grows on concrete, rocks, brick walls and other structures, even on gate posts where birds have sat and defecated.
                                               Sphagnum moss
 
 
Pleurocarpous mosses
These species have highly branching stems, and tend to sprawl through grass or grow closely as mats over the substrate. The sporophyte stems and capsules arise from among the branches, not from the tip of the stem.  There are fewer species of these than the acrocarps, but they can be very prominent in lawns for example.
 
 
Springy turf-moss  Rhytidiadelphus squarrosus
 
This is one of the commonest mosses you will find in your lawn, but it also grows in all sorts of grassland that is not too long. This is a pleurocarpous moss that threads itself through the grass. Its most distinctive features are the leaves that turn down at the ends – stick out your arms and turn your hands down – that is what I mean, but about a third of the leaf is turned down. This gives the shoots a star-like appearance. Look closely beneath the leaves and you might see the red stem – another diagnostic feature. The leaves have a broad base with two very short nerves, and a long, narrowing upper section which bends down.
 
Don’t worry if your lawn seems mostly to be moss – this is fine – it is green, it does not grow much, so you don’t have to cut it, and it puts lots of carbon back into the soil. Avoid those moss killers and think about all the little animals that you might find in the moss instead.
Rough-stalked feather-moss Brachythecium rutabulum 
 
This is another very common pleurocarpous moss in all our gardens on stones, on wood, amongst the flowers, in shade or light and in the grass.  Look out for the metallic sheen to the shoot ends. It forms loose, medium-sized robust patches with irregular, ascending or erect branches with egg-shaped spreading leaves. The nerve here is up to about halfway along the leaf which has only a short sharp point, not drawn out like in Rhytidiadelphus.
Redshank Ceratodon purpureus
 
This very common moss grows into cushions coloured from light green through to purple.  The capsules and the setae are characteristically purple-red.  Unlike the other acrocarps described here, it prefers acidic conditions, but is still commonly found throughout Britain and Ireland on walls and roofs, on bonfire sites and in garden lawns.
Mosses
 
Mosses are formally classed in the taxonomic division Bryophyta which is slightly confusing because the common term "bryophytes" also includes liverworts and hornworts. There are about 12,000 described species globally, and 763 in Britain and Ireland.  For our size, we have an exceptionally diverse moss flora, probably because we are a cool, temperate and soggy set of offshore islands.
 
Mosses are well represented in a number of garden habitats, especially in lawns where they are not always considered welcome. The BUGS project1. identified 64 species from 61 domestic gardens in Sheffield, of which 10 were found in lawns.  One species Kindbergia praelonga was present in nearly all lawns, while many others only appeared once or twice. As well as lawns, garden mosses are found in rotting wood, on garden furniture, walls and roofs, and growing on damp soil.  There is much scope for keen amateurs to add a lot to our knowledge of garden moss flora, especially since the species you find will differ a lot depending on soil conditions, and how far north or west you are.  In general, moss floras are most diverse in the north and west of these islands, and on acidic soils.
 
Types of moss
 
We can divide moss into two basic groups, the upright or acrocarpous mosses, and the sprawling pleurocarpous mosses. For identification, you need to look at the tiny leaves with a lens.  Are they serrated like a knife around the edge or some of it; what shape are they and do they have a central nerve or not – sometimes there is one for a little way, sometimes more than one, and in some mosses these nerves extend out at the leaf end, sometimes into a whispy hair point. These can be coiled, reflexed or grey when dry. It helps identification to note where you found your sample - was it on wood, concrete, stone or soil, was it in grass or some other garden feature?
 
The common names of mosses are not traditional, have been invented recently, generally reflecting the mosses' appearance to help remember them. The scientific names are tongue-twisters, but great fun.  Try saying the Latin names as if they are poetry – some sound really lovely.
 
Acrocarpous mosses
 
These mosses have just a single stem with the leaves arranged up it, this may fork or have a few short branches, but basically the habit is vertical growth, as opposed to the branching and sprawling pleurocarpus mosses below. They all bear the sporophyte capsules from the tip of the stem.
 
 
 
 
Grey-cushioned grimmia Grimmia pulvinata  
 
The compact, often hemispherical cushions of this upright, acrocarpous moss are often hoary-grey as the long hair-points dry out. Look for it on roofs, tops of walls or on any stonework where it can be very common. The leaves on the single stem are oblong, but long and fairly narrow, with a nerve from bottom to top extending into a long silvery hair-point that may equal the leaf length, when dry these crinkle up. This feature and its neat rounded overall colony form is responsible for another common name "hedgehog moss".  
 
There are usually oval capsules on long, curved setae (stems) which tend to bury the capsule back into the cushion while it is young. This is a very distinctive diagnostic feature. 
Bonfire-moss Funaria hygrometrica 
 
This really does live up to its name as it colonises old bonfire sites readily as well as bare soil elsewhere. It is a common acrocarpous species being a little upright moss which forms loose carpets on the ground. It has egg-shaped leaves, 2-4mm long and an abundance of asymmetrical, yellowish to orange-brown capsules with a lovely little delicate ‘hood’ with an extended beak like a pixie hat.   
Wall screw-moss Tortula muralis
 
This is easy to identify as it grows in neat little cushions less than 1cm tall, usually on walls, concrete, roof tiles or stones, mostly in the open, but can tolerate some shade. The leaf’s nerve extends as a conspicuous, long, silvery hair-like projections from the end of the leaves which make the cushion look hoary grey when dry. You will need a magnifying glass to see the leaves which are tongue-shaped 2-3.5mm long, and twist and curl when dry, but spread out from each other when moist. The cushion is usually also marked by 1-2cm long purple setae (stems) with erect narrow cylindrical capsules at the top. 
 
This is one of the commonest mosses you can find on walls and tiles.
Capillary thread-moss  Bryum capillare
 
This is another compact acrocarpous moss that grows in small tufts or patches 1-2cm tall. It is very common on soils, in grassland, on trees or logs, fences, walls, roofs or rocks everywhere. Dry plants typically show corkscrew-like shoots, with the leaves spirally twisted around the stem. The broad leaves are only 2-5mm long and are widest about their half-way point – but you will need a magnifying glass to see these clearly. Unlike the wall screw-moss, the capillary thread-moss has capsules that are drooping but borne on reddish seta up to 3cm tall. 
White-tipped bristle-moss Orthotrichum diaphanum
 
Another little upright moss, this one has white leaf tips which are diagnostic. It grows in little tufts of narrow, upright shoots up to 1cm tall, usually with abundant capsules. The leaves are 2.5-4mm long and the capsules, which are tucked into the leaves rather than on long seta, are covered in a hairless light green cap when fresh but are brown and furrowed slightly when old and dry. The leaves are held more or less straight and spread out when moist.
 
This moss is common and widespread on trees and shrubs, especially willows and elder which have nutrient-enriched bark, but it also grows on concrete, rocks, brick walls and other structures, even on gate posts where birds have sat and defecated.
Silver-moss  Bryum argenteum
 
This little upright moss is easily recognised owing to its pale-green or almost white colouring in compact tufts or patches which look shiny and silver grey when dry. The shoots tend to be crowded, small – usually less than 1cm, and the leaves are rounded and concave giving the shoots a smooth cylindrical appearance, whether wet or dry. If you look closely at a leaf, you will see the nerve ends well below the tip and may have a silvery tip. Little pendulous capsules about 1.5mm long grow on a short seta in autumn or spring. This little moss grows on disturbed habitats which are usually dry and low in nutrients, so look for it on poor soils, by paths, in the cracks between paving stones, on walls, buildings, roof, concrete and tarmac.
Redshank Ceratodon purpureus
 
This very common moss grows into cushions coloured from light green through to purple.  The capsules and the setae are characteristically purple-red.  Unlike the other acrocarps described here, it prefers acidic conditions, but is still commonly found throughout Britain and Ireland on walls and roofs, on bonfire sites and in garden lawns.
 
 
 
Springy turf-moss  Rhytidiadelphus squarrosus
 
This is one of the commonest mosses you will find in your lawn, but it also grows in all sorts of grassland that is not too long. This is a pleurocarpous moss that threads itself through the grass. Its most distinctive features are the leaves that turn down at the ends – stick out your arms and turn your hands down – that is what I mean, but about a third of the leaf is turned down. This gives the shoots a star-like appearance. Look closely beneath the leaves and you might see the red stem – another diagnostic feature. The leaves have a broad base with two very short nerves, and a long, narrowing upper section which bends down.
 
Don’t worry if your lawn seems mostly to be moss – this is fine – it is green, it does not grow much, so you don’t have to cut it, and it puts lots of carbon back into the soil. Avoid those moss killers and think about all the little animals that you might find in the moss instead.
Rough-stalked feather-moss Brachythecium rutabulum 
 
This is another very common pleurocarpous moss in all our gardens on stones, on wood, amongst the flowers, in shade or light and in the grass.  Look out for the metallic sheen to the shoot ends. It forms loose, medium-sized robust patches with irregular, ascending or erect branches with egg-shaped spreading leaves. The nerve here is up to about halfway along the leaf which has only a short sharp point, not drawn out like in Rhytidiadelphus.
Common feather-moss Kindbergia praelonga
 
This is a more regularly branched, weakly scrambling pleurocarpous moss with a roughly triangular outline. It is distinctive if you look closely with a lens in that the branch leaves are much smaller than those on the stems, which are triangular-shaped but with a long, fine elongated tip which often turns outwards. These leaves are about 1.5mm long, so you need to look carefully with a hand lens. The nerve goes to the end of the branch leaf.
 
This neat little common moss sprawls on banks, in lawns, on the ground under trees or on their trunks and on logs.
 
References - see also Bryophytes page
 
1.  Smith, R.M, Thompson, K. Warren, P.H. and Gaston, K.J. (2010) Urban domestic gardens (XIII): Composition of the bryophyte and lichen floras, and determinants of species richness. Biological Conservation 143:873–882
 
2. Garden Organic Defra delays again on peat ban 
 
Page written by Penny Anderson, compiled by Steve Head
 
 
 
Sphagnum - bog mosses
This important genus belongs within the acrocarpous mosses, although it looks superficially like the next group of pleurocarps. There are about 35 species of Sphagnum recorded in Britain and ireland, and most are confined to the wet acid bogs of the north and west,especially Wales, Scotland and Ireland, but some species (eg S. fallax and S. denticulata) are found in lowland fens, ditches and boggy habitats in England too.   These mosses are all characterised by having leaves arranged in spiral whorls around their straggly stems, and having at the tip a capitulum or ‘head’ which is a rosette of leaves forming a dense mat at the top of the plant.
 
Most prefer low-nutrient and acidic conditions, where over millennia they can accumulate metres of depth of dead plant material we harvest as peat for fuel and compost.   Peat bogs have suffered greatly from effects of acid rain in areas close to urban centres, peat harvesting and drainage, and these special habitats need urgent protection. Peat bogs release a lot of CO2 to the atmosphere as they dry out, and conversely absorb it in large amounts and lock it away safely when they flourish.  It is very important that as responsible gardeners we all avoid the use of peat-based composts now. Legislation is planned to ban its use from 2030, but this issue has been live since 2010, and little progress has been achieved.2.  We discuss the issues of peat in gardening, and its substitutes here.
 
Dried Sphagnum can absorb prodigious quantities of water, and has anti-bacterial properties, so was extensively collected and used for treating wounds and stopping bleeding on a large scale in World War I. It may have been an important preserving material for early people carrying putrescible food on raiding or hunting trips.
 
Since most gardens are at low altitudes with fertile soil, Sphagnum species won't often be found naturally unless your garden is unusually soggy- as are many are on Exmoor or Dartmoor for example.  Lowland gardeners can buy live Sphagnum and cultivate it to create habitats for orchids and carnivorous plants. 
 
                                             Sphagnum moss
 
Pleurocarpous mosses
These species have highly branching stems, and tend to sprawl through grass or grow closely as mats over the substrate. The sporophyte stems and capsules arise from among the branches, not from the tip of the stem.  There are fewer species of these than the acrocarps, but they can be very prominent in lawns for example.
Sphagnum - bog mosses
 
This important genus belongs within the acrocarpous mosses, although it looks superficially like the next group of pleurocarps. There are about 35 species of Sphagnum recorded in Britain and ireland, and most are confined to the wet acid bogs of the north and west,especially Wales, Scotland and Ireland, but some species (eg S. fallax and S. denticulata) are found in lowland fens, ditches and boggy habitats in England too.   These mosses are all characterised by having leaves arranged in spiral whorls around their straggly stems, and having at the tip a capitulum or ‘head’ which is a rosette of leaves forming a dense mat at the top of the plant.
 
Most prefer low-nutrient and acidic conditions, where over millennia they can accumulate metres of depth of dead plant material we harvest as peat for fuel and compost.   Peat bogs have suffered greatly from effects of acid rain in areas close to urban centres, peat harvesting and drainage, and these special habitats need urgent protection. Peat bogs release a lot of CO2 to the atmosphere as they dry out, and conversely absorb it in large amounts and lock it away safely when they flourish.  It is very important that as responsible gardeners we all avoid the use of peat-based composts now. Legislation is planned to ban its use from 2030, but this issue has been live since 2010, and little progress has been achieved.2.  We discuss the issues of peat in gardening, and its substitutes here.
 
Dried Sphagnum can absorb prodigious quantities of water, and has anti-bacterial properties, so was extensively collected and used for treating wounds and stopping bleeding on a large scale in World War I. It may have been an important preserving material for early people carrying putrescible food on raiding or hunting trips.
 
Since most gardens are at low altitudes with fertile soil, Sphagnum species won't often be found naturally unless your garden is unusually soggy- as are many are on Exmoor or Dartmoor for example.  Lowland gardeners can buy live Sphagnum and cultivate it to create habitats for orchids and carnivorous plants. 
 
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