A developing covering of moss can soon make a new stone structure look at home in the garden. Cushions of moss tossed down from rooftops on to pavements show that among the leaves the birds have been finding a plentiful supply of minute insects.

For bryologists, mosses and liverworts are a focus of study from which they can learn much about the habitats in which these often overlooked plants are found.

“Bryophytes, or bryoflora, also help to maintain soil, moisture, and, in the micro-habitats among their moist leaves they supply the microscopic organisms which provide food for the smallest of the insects,” said Jacqueline Wright, who is county recorder of mosses and liverworts for both Oxfordshire and Berkshire.

Mrs Wright is a member of Shotover Wildlife, the voluntary organisation which was founded in 1999 to research and communicate the importance of Shotover Hill for wildlife.

It was through her initial interest that she discovered the important part mosses and liverworts have to play in the natural environment.

“Part of my role is to raise the profile in the two counties of the interest there is to be found in the varieties of mosses that we have here,” said Mrs Wright.

She described herself as “an amateur specialist”, self-taught in her subject. “My own background is in nursing, and I came into wildlife just by growing to love our local wildlife reserve at Shotover.

“I wanted to become involved there, and I wanted to do something to contribute to its conservation work.

“I started with a little wildflower guide and taught myself from the book and by looking at the plants on Shotover. Bryophytes came from that.

“I discovered that Shotover is known historically for having one of the earliest collections of mosses and liverworts in the world. Because this is important, and that there are these historic records, because nobody else was doing any recordings of bryophytes locally, and with our organisation focusing most of its work on Shotover, I felt almost a moral obligation to take up this work.

“I decided to cover that group of plants and the important part that they play in the ecological balance of the reserve. I felt that I should focus my attention on this group in order to get a full over-view.”

Among the many activities of members of Shotover Wildlife are species surveys — which they publish — practical conservation management for wildlife, and working with students in furthering their studies. As well as at Brasenose Wood and Shotover Hill, an area designated as a Site of Special Scientific Interest (SSSI), members of the group also work further afield on other wildlife sites across Oxfordshire.

At Shotover, the study of bryophytes presents opportunities for coming across new, as well as already-recorded, species. “I am making new discoveries all the time,” said Mrs Wright. “I am still getting new records.”

In Oxfordshire there are some 400 species recorded.

“On Shotover there are some species that are regionally rare. Through our surveys, several species have been rediscovered, after having been reported in the past as extinct on the hill,” she said.

These include the Squirrel-tail Moss, the Frizzled Pincushion and the branching Lateral Cryhaea, one of several species that are being monitored.

“The interesting diversity of bryoflora to be found at Shotover is due to the different types of habitat, such as damp woodland and scrub, old field boundaries, marshy ground and the bare soils of the heath,” said Mrs Wright.

Its heathland, with its acidic soil, is a rare habitat in Oxfordshire, and some mosses thrive in this acidic environment. A particular example is the tiny Bristly Haircap, which is rare and otherwise declining in the county.

In Britain, there are about 1,000 bryophyte species, representing some 70 per cent of those to be found in Europe. Worldwide they number about 22,000.

Mosses and liverworts are among the first land plants to have evolved 400 million years ago.

“That Great Britain has such a great range of species is due to its great diversity of geology and topography, and its wet climate,” added Mrs Wright.

Bryophytes can provide a great deal of information about a habitat, such as rock type, soil acidity, geological substrate, the age of woodland and — particularly important in these times — even the presence of air pollution. They can also play a role in the creation of soil, and in its stabilisation against erosion.

Mosses and liverworts are not easily differentiated by normal visual inspection, and need to be examined under a hand-lens or microscope. Both are plants which are most likely to be found in damp surroundings.

They grow on the more sheltered side of hillsides, on rocks, on the bark of trees, on walls and on roofs. They often favour north-facing surfaces, where the moisture in the ground will not be dried quickly by the sun, and will provide humidity.

“Mosses are one of the first plants to colonise bare patches,” said Mrs Wright. “They are gap-fillers. They don’t like competition, they like to get in first. Big plants will crowd them out.”

In dry weather, they will stop growing, shrinking as they dry out but being revitalised by fresh moisture. Some, however, have special features to protect them from this drying out.

They propagate themselves by spores, developed in the capsules which are produced instead of flowers. These spores are wind-borne; when and where the conditions are right, they will germinate. Bryophytes do not have roots. They have small anchoring hairs so do not need much soil in which to become established.

For people who have found an interest in bryology, courses are held once a year, in November, during ‘the mossing season’.

This is when these plants are most visible, and not overshadowed by spring and summer growth of other plants.

Groups are kept small so that the learners, who come from all over the country, can have plenty of individual assistance — a necessity because of the complex nature of the subject.

From these courses has come the Oxford Mossing Group, to provide continuing support for the learners.

“They will need support for some time,” said Mrs Wright. “We continue throughout the mossing season, all going out looking for mosses. The students bring them to me to check if they have found the right name and we have microscope sessions so that they can examine their finds.

“Identification is not easy,” added Mrs Wright. “That is why there are not many people doing this type of survey — it is high-powered microscope work — looking at the cell-structures, spores and other aspects of each plant.”

In her own survey work, Mrs Wright travels around Oxfordshire and Berkshire, and supplies records to the Thames Valley Environmental Record Centre, and to the national bryological recording scheme.

Although the study of mosses and liverworts is a complex one, anybody can make their contribution to Mrs Wright’s recording work.

“If the theory of mosses is not for you, it doesn’t matter — you can still alert me to something that might be of interest.

“There is a role for the non-specialist, for members of the enthusiastic public who are tuned in to what is around them.”

Anybody who would like to send in reports to Mrs Wright can do so via email to Shotover Wildlife at enquiries@shotover-wildlife.org.uk