Update on Liverworts and Mosses
Because of my limited knowledge of the bryophytes - the group that includes liverworts and mosses - I have been aware that this group is sadly under-represented on this website. In an effort to do just a little about this, I have re-looked at some of my own records, got some information from Roger Snook - a local naturalist - and have done a search for some older records from the study area.
Looking at my old records to a great extent involved looking at some microscope-slides that I prepared back in 1979 and 1980 when I collected and preserved some samples. With Roger's help I was able to either confirm those early identifications or - in some cases - to exclude them. As well, I gathered some new samples and attempted identification of those, and in the main was pleased that they agreed with samples from all those years ago gathered from similar locations.
In this way I was able to add a few more species to the list on the website, and add a few more still with Roger's records and knowledge of local species. The list is available here.
Lastly, I trawled through the "Flora of Essex" by Stanley T. Jermyn for any local records included there, so that these records are now also available on this website. Those records included a number of species of Sphagnum, which is well known to exist in boggy habitats. Although when walking across areas like Leyton or Wanstead Flats after heavy rainfall we may think of these areas as boggy, most of the Flats dry out very rapidly, so no true bog remains. The locations where the sphagnums were found appears to be closer to that area of Leyton Flats nearer to the Green Man and to Snaresbrook. Roger particularly bemoans the loss of those "boggy" areas which we knew on Wanstead Flats - particularly the area below the spring which used to exist south-east of the mini-roundabouts at the junction of Aldersbrook and Centre Roads, and the just-about-still-wet area to the north of the fairground site.
The spring was always a bit of a mystery (as springs tend to be - unless you go into the geology and spoil it!). It was on the slope of the bank that runs down from the rising land at the north of the Flats to the area known as the Dell on Epping Forest maps, but may be more appropriately called the Brick-fields for historical reasons. It is now playing fields. The water bubbled and sometimes flowed from the mud near the upper slope, and gave rise to a wet area at the base. It was much favoured by feeding and drinking birds, and flowed permanently even if sometimes sparsely until pipe-works were carried out along Centre Road. Whether this simply resulted in the repair of a leaking main or cut a natural water supply from the vicinity of Bush Wood, I do not know. The spring is no longer and little remains of the interesting plant habitat that existed in the wet area.
The boggy area on the fairground section of the Flats (ie west of Centre Road) still exists, although is no longer anything like as permanently wet as it used to be. It would require a geologist, I suppose, to explain exactly why that area is particularly wet, but suffice to say its drying out may well be influenced by the now-considerable growth of birches and other trees that have invaded. Perhaps some thoughts may be given to actually channelling water into these area? After all, the roads nearby (in this case probably most likely Lake House Road) must have considerable water running into surface-water drains during rainfall.
Looking more at the species that we do know of in these areas, there are known to be two species of Lophocolea liverworts present - L. bidentata and L heterophylla, but they can be difficult to tell apart. The liverwort Marchantia polymorpha is also associated with damper areas, and used to be more frequent on the sides of the ditches that exist around the perimeter of the Flats. It is probably more common now in gardens. Regarding mosses, Polytrichum commune is perhaps most associated with these wetter area as it favours damp moorlands and this is the closest that we have got! Because of its size it is an easily-observable plant and quite widespread in suitable habitats. In the usually drier parts of the Flats the moss Brachythecium albicans is frequently found in the grassy areas, with Brachythecium rutabulum probably also present as it is a very common moss of grassy places. For some reason, though, I do not have a definite record of it here as I do for the City of London Cemetery. Outside of the grassy areas, where the soil is more open due to compaction or fires, Funaria hygrometrica is very common, forming sometimes quite large mats and when in fruit, distinctive down-turned capsules. Ceratodon purpureus is another very common moss on barer parts of the Flats and elsewhere, forming rather dull-looking carpets unless in fruit when it is conspicuosly purple. It also favours burnt-ground, which is a situation that occurs quite frequently during the summer months. Also absent from my Flats records, although it must be present as it is such a common moss, is Hypnum cupressiforme, which again is present in the cemetery. Another species of Polytrichum - P. juniperinum - is easily observed in numerous areas, particularly perhaps just south of Alexandra Lake where the crows delight in pulling tufts out to search for goodies beneath.
On garden walls in the streets nearby may be found another liverwort, Lunularia cruciata, as well as the mosses Bryum capillare and Tortula muralis, both upright (acrocarpus) mosses and Bryum argenteum which has a spreading (plerocarpus) habit. Barbula convulata as well as others should also be present in these habitats, with Grimmia pulvinata particulary on rooftops.
In the wooded areas, Hypnum cupressiforme is common, and there are probably varieties of these present which need to be determined. Mnium hornum is an acrocapus moss which is common in numbers of places throughout the area, whilst Fissidens taxifolius is probably common but is perhaps not so noticeable.
It will be evident to anybody with a knowledge of mosses and liverworts that this account and the species listed is sparse. There may well be aspects that need to be clarified or even changed. But at least I hope this will serve as an introduction to this group of plants that - by nature of their relative size perhaps - are not so frequently taken into account when looking at plants in general.
Paul Ferris, 23rd December 2011