Wales is fortunate in having some particularly fine broadleaf woods, particularly concentrated in North-west Wales. These are usually damp, and relatively free of pollution and disturbance by man.

The mosses and liverworts to be found depend to some extent on the nature of the soil and underlying geology (which will also be reflected in other plants, including the trees). Thus, an ash-dominated woodland on a soil rich in calcium and with a neutral or basic pH will have a somewhat different range of species to an acidic, nutrient-poor upland oakwood.

Some of the mosses and liverworts which occur in Welsh woodlands are listed below:

Mosses

Dicranum scoparium

This is a prominent moss in many habitats, being tolerant of a wide range of conditions, from acid to neutral. Its leaves are long and tapering to fine points, and toothed towards their tips. A nerve runs the entire length of the leaf, and groups of orange-brown cells occur in the basal angles. The stems are erects,with the leaves often tending tocurve in one direction (a conditionknown as secund). In woodlands, may be confused with the close relative, Dicranum majus.

Eurhynchium striatum

Occurs on the ground or on tree bases in woods where there is some calcareous content to the soil. It is a robust species with stems held quite rigidly, giving a bushy appearance. The leaves are heart-shaped, with an acute tip, and finely-toothed margin. A nerve runs to about three-quarters the leaf length.

Hookeria lucens

This moss is sometimes mistaken for a liverwort with its complanate (flattened) shoots and its translucent leaves which have no nerve. The leaves are large (about 5mm long) and ovate. The translucent appearance is partly due to the remarkably large cells of the leaf, can be just made out with the naked eye and are very clear with a lens. It is a plant of humid, shaded conditions, and is often found on the banks of streams in sheltered wooded valleys in Wales, as well as in other habitats

Hylocomium splendens

In Wales this a moss mainly of upland acid woods, heaths, degraded and drying blanket bogs, and roadside banks. A fairly robust plant, which with its flattened, regularly-branched shoots has a somewhat leaf-like appearance. Its stems are red in colour (a useful feature in distinguishing this from the similar Thuidium tamariscinum) and covered in minute leaf-like structures (paraphyllia) in addition to the normal leaves. It is sometime known as the 'pick-a-back' moss because of the way new season's shoots grow up from the 'back' of the previous season's shoots.

Hypnum cupressiforme

A very common moss, and indeed the commonest pleurocarpous moss in Wales and the rest of Britain (one of the reasons for this is that it is pollution tolerant). It grows on trees, tree-stumps and logs, as well as on rock outcrops, walls, roofs etc. It can tolerate shaded or exposed conditions. The plant has a characteritic appearance with the leaves tapering to fine points and curved like a sickle. The nerve is very short and double.

Isothecium myosuroides

This species grows abundantly on rocks and on tree bases, often becoming dominant in these situations. It is recognised by its "sub-dendroid" arrangement of stem and branches - i.e. they are arranged with the branches clustered together somewhat like the branches of a tree. The leaves are longly triangular, drawn to a fine point, with toothed margins, and distinct green or brown auricles

Leptodon smithii

A moss which grows on tree boles and trunks in woods, but also in more open situations such as parklands and hedgerows. It is common in Mediterranean countries, and in Southern England, but in Wales is at the edge of its European range. It is recorded post-1950 in only three 10km squares in Wales. In a dry condition, individual shoots are ncharacteristically curved upwards, and the leaves are tightly clasped to the stems. When wet the plant has a quite different appearance, with the leaves and branches spreading. Individual leaves are ovate, with a rounded tip and one margin recurved. The nerve is faint, one-quarter to one-half the leaf length.

Leucobryum glaucum

This moss is readily recognised once known, and is unlike any other British species (except the rarer Leucobryum juniperoideum). It forms tightly-packed cushions which can be anything from a few centimetres to over a metre across, which are pale-green to almost white in colour. The leaves are elongated, and without a nerve. As well as in woodlands, it also occurs commonly in many wet peatlands.

Mnium hornum

This is a common moss in a wide variety of habitats, and in woodlands it is often abundant, on banks, on tree bases and on rocks. Its leaves are more or less parallel for most of their length, tapering to a point at their tip. The leaf margins have a border of narrow, elongated cells, and teeth which occur in pairs. In colour the plants are a dullish dark green, but in the spring the light green of new shoot tips provides a marked contrast.

Plagiothecium nemorale

A moss of earth banks, tree-bases and streamsides in woodlands and hedgerows, this has a flattened (complanate) appearance but rather less so than the previous species, is a darker green, and lacks the transverse undulations of the leaves. The leaves are ovate, tapering to an acute tip, and have a double nerve to just under half their length.

Plagiothecium undulatum

This moss has a flattened ("complanate") appearance, and is pale-green to almost white in colour. Each leaf is crinkled, or undulate, which helps to distinguish this from related species. It grows on the ground or on tree bases in woods, and is moderately common.

Polytrichum formosum

This is a distinctive moss with sharply-elongated, toothed leaves arranged spirally around an erect, unbranched stem. It is commonly found with capsules which are held erect on a long seta.

Rhytidiadelphus loreus

This moss can be abundant on the ground in woodlands, and is distinguished by a reddish stem, with the leaves having the appearance of being swept to one side of the stem and branches.

 

Thuidium tamariscinum

This is an abundant species on hedgerow banks as well as on the ground in woodlands. With its regular branching and triangular overall shape it somewhat resembles a small fern.

Ulota crispa

This is a very common species on the branches of trees and shrubs in Wales. It forms neat, rounded cushions usually with abundant capsules. The leaves are long and narrow, with a nerve running their entire length, and are characteristically curled and crisped when dry . The immature capsules are capped with a notably hairy calyptra.

Zygodon conoideus

This small epiphytic moss occurs most frequently on tree species with a nutrient-rich, fairly basic, rough-textured bark, in particular elder and ash. Its leaves are longly ovate and pointed, with a clear nerve. Cells are more or less rounded inmost of the leaf, and are strongly papillose. The axils of the leaves contain tiny multicellular gemmae (multicellular propagules) which can barely be seen with a hand lens. Under the microscope characters of the gemmae are important for separating this from other species of Zygodon.

Liverworts

Adelanthus decipiens

This beautiful leafy liverwort is a glossy mid- to dark- green in colour when wet, almost black when dry. The leaves have from 0 to 3 prominent teeth on their margins. This is a Nationally Scarce species in the UK and in Wales is restricted to the semi-natural oakwoods of the North, on rock outcrops.

Bazzania trilobata

A very characteristic species of acid oak woodlands in Wales. It grows in clumps on soil, tree bases and boulders, with the stems usually forked towards their tips. The appearance is often that of a cluster of green caterpillars stuck on their ends to the substrate!. The lateral leaves are shallowly divided into three lobes (hence the specific name "trilobata").

Cololejeunea minutissima

As its specific name implies, this leafy liverwort is tiny. The lateral leaves are each lobed and folded to form a shape like two hands cupped together. This arrangement may facilitate water retention. This species is found in crevices of bark on trees, and sometimes gorse and ivy, rarely far away from the sea. In appearance it is very like the related Lejeunea ulicina, but the latter species differs in having an additional row of (even smaller!) leaves.

Diplophyllum albicans

A very common leafy liverwort on acid soils and rocks. Its lateral leaves are each divided into two lobes, with the smaller lobe folded back upon the larger one, giving the impression that there are four rows of leaves. The species is easily identified in the field by checking for the presence of a band of colourless cells running down the middle of each leaf lobe - a kind of false nerve.

Frullania dilatata

This is a common leafy liverwort on woodland trees. It often forms almost circular rosettes, with individual stems closely adpressed to the bark, a dull-green to purplish-brown in colour. This is another species where the lateral leaves are each divided into two lobes. In this case, the smaller lobe, which lies on the underside of the plant, is folded into a helmet-shaped structure, which may have a role in water retention.

Lepidozia cupressina

A species very characteristic of damp oakwoods in North-west Wales where it can occur in some abundance as large cushions on the tops of rocks, tree bases and stumps, rotting logs and soil.It is rather rare in the rest of Wales. The leaves, which are 3- or 4-lobed, are closely overlapping, rather like the those of the Cypress tree.

Metzgeria furcata

This is a thallose liverwort which forms flattened pale- to mid-green patches on tree trunks. The thallus branches are narrow, reaching only about 1mm in width. A narrow but clearly-defined midrib is present.

Plagiochila asplenioides

This is a large leafy liverwort, unlikely to be confused with any other once known (other members of the genus are considerably smaller). It has a glossy, semi-translucent appearance, and grows on the ground, often on shaded banks, or soil-covered rocks in lowland woodlands. It prefers calcareous or nearly neutral soils.

Plagiochila atlantica

Only known from two sites in Wales. Elsewhere in the British Isles it only occurs with any degree of frequency in parts of Western Scotland. Outside of Britain it is known from only one site in France, so is almost endemic. It grows in humid broadleaf woodland where there is a high degree of humidity, usually on rock outcrops and boulders.

Radula complanata

This leafy liverwort occurs on trees, and less frequently on rock, as pale-green patches flattened against the substrate. Each lateral leaf is divided into two lobes, the smaller lobe folded under the larger. The species is remarkable in that the rhizoids grow on the smaller leaf lobes, rather than directly on the stem.

Saccogyna viticulosa

This leafy liverwort has entire lateral leaves which are arranged in nearly opposite pairs along the stem. It grows typically on moist, acid rock ledges in sheltered wooded valleys, especially near the sea.

Scapania gracilis

This leafy liverwort is found (often abundantly) on tree bases, logs and rocks in acidic oak woodlands in Wales, sometimes in more open habitats. One of the larger Scapania species it has the typical bilobed and folded leaves of the genus - in this case, the upper (antical) lobe is curled back on itself, away from the stem.

Trichocolea tomentella

This liverwort is highly unusual in that its leaves are very finely divided into segments which are ultimately only one cell wide (this is hard to see with the naked eye, but is clear with a lens). The overall appearance of the plant is of a rather flattened, branched structure, pale green in colour. It is found most often in damp woodlands in seepage zones and wet flushes with some base enrichment.