Worcestershire Record No. 19 November 2005 pp. 55-56
Harry Green drew my attention to the following 1901 account of Worcestershire’s Lichen Flora. It gives a tantalising glimpse on the status of our past flora. However, since then some of the species mentioned are now lost. Nevertheless, the article gave me a very welcome opportunity to discover some of the changes that have occurred between 1879 and 2005. During this period there have been many alterations in synonyms and wherever possible these have been updated and are given as bracketed additions. Other comments are included in [ ] brackets.
The Victoria History of the Counties of England.
Published for the University of London Institute of Historical
Reprinted from the original edition of 1901
By Dawsons of Pall Mall Folkestone and London 1971
These are a large and well-known class of plants, usually abundant where the air is pure and uncontaminated by the smoke and poisonous gases of towns and other industrial centres. They are found in all regions, tropic or arctic, and at all elevations, from sea-level to the snow-line of the highest alps; they can endure every degree of cold, and revive after the drying heat of even tropical climates; and their length of existence as individuals is almost indefinite.
Formerly they were considered to be a distinct class of plants intermediate between the algae and the fungi. But the researches of some of our more learned botanists, as Schwendener and others, have proved them to be in reality fungi, allied to the Ascomycetes, parasitical on certain of the Algae – Protococcus, Chroococcus, Nostoc – and some of the Confervaceae. Some are crustaceous as in Cladonia, others foliaceous as in Parmelia, and others fruticose as in Usnea barbata (Usnea filipendula). In the neighbourhood of large towns, or where the atmosphere is charged with smoke, they are rarely found, or only in an abnormal state, forming dust-like or filamentous patches on walls or trees, etc., and known by the older botanists by the pseudo-generic name Lepraria.
In the north-eastern portion of the county lichens are rarely found, save in the abnormal state referred to above. But at Hartlebury Common there are still in existence the remains of a lichen flora, such as Cladonia rangiferina, C. furcata, C uncialis and Ureceolaria scruposa (Diploschistes scruposus), and at Bewdley Lecidea dispansa (Micarea erratica) has been found. The Clent Hills have not been fully worked, and so not appear to have any special species. The Lickey Hills, which lie a little south of this, have within recent times been rich is some of the more common species. Here are found Cetraria aculeata, the black-fruited Verrucaria epigaea, (Thrombium epigaeum) V. nigrescens and V. rupestris (V. muralis). But as soon as we approach the more sylvan portions of the Severn Valley near Worcester, lichens are not only more frequent but more noticeable; trees, walls, the stone coping of bridges, and wild waysides each yield their quota of lichens, some of them rare, such as Leptogium lacerum, var. pulvinata (Leptogium lichenoides) L. subtile, Sphinctrina turbinata, (Sphinctrina tubiformis) Calicium phaeocephalum (Chaenotheca sp.), C. curtum (Calicium abietinum ), C. trichiale (Chaenotheca trichialis), Sticta pulmonaria, (Lobraria pulmonaria) Lecidea incompta, (Bacidia incompta) L. rosella, (Bacidea phacodes or B. rubella), the singular parasitical L. Parmeliarum (Abrothallus parmeliarum, a lichenicolous fungus, not a lichen) and Opegrapha Turneri (Opegrapha herbarum).
But the richest district in the county is that of the Malvern Hills and the adjacent common lands, where the lichens are numerous and often rare. Here are found the beautiful coral-like Sphaerophoron compressum (Bundophoron melanocarpon) and S. coralloides, (Sphaerophorus fragilis or S. globosum), Baeomyces rufus, B. roseus, Stereocaulon namum (Leprocaulon microscopicum) Platysma glaucum (Platismatia glauca), Parmelia saxatilis var. omphalodes (Parmelia omphalodes), Umbilicaria pustulata (Lasallia pustulata), Amphiloma lanuginosa, (Leptogium membranaceum), Lecanora ferruginea, (Caloplaca ferruginea), L. Haematomma (Haematomma ochroleuceum); Lecidea tenebrosa (Schaereria fuscocinerea). L. tricolor (unknown ) L. muscorum (Massalongia carnosa), L, truncigena, (Gyalecta truncigena), Opegrapha vulgaris, O. lyncea (Lecanactis lyncea), and on the hollies of Hollybush Hill are several of that curious genus Graphis, as G. elegans, G. scripta, G. horizontalis (G. scripta), G. Serpentina (G. scripta), Verrucaria gemmata (Acrocordia gemmata), V. biformis (Anisomeridium biformis): on calcareous rocks, Verrucaria Salweii (Acrocordia salweyi) and Endocarpon hepaticum (Catapyrenium cinereum). On heathy places on or about the hills [Bredon Hill?] the singular family Collema are numerous, such as C. flaccidum, C. crispum, C. nigrescens, and their allies, Leptogium lacerum (Leptogium lichenoides), L. tenuissimum; and on old oaks in Cowleigh Park, Trachylia tigillaris (Cyphelium tigillare).
As we travel farther south to the Avon Valley, the trees are
more richly clad in their grey clothing of Lichens. [These are probably species
of Parmelia and Physcia ] In the outlying portion of the county
– Broadway and the high land about Bredon, where the rocks are capped with
oolite, and the fences are of stone from the neighbouring quarries. The lichens
are abundant and some of them rare, such Verrucaria immersa, (Thelidium
decipiens) V. rupestris (Verrucaria muralis), as Lecanora calcarea (Aspicilia
calcarea), Verrucaria rupestris and its variety muralis (Verrucaria
muralis). In some places the broken rock is curiously stained inky black with
the thallus of Pannaria nigra (Placynthium nigrum), and in others a
yellow tinge prevails from the abundant thallus of Placodium murorum (Caloplaca
saxicola). Now and again on the higher rocks is Lecidea geographicum (Rhizocarpon
geographicum) [These species are only found on acidic rocks, is the author
referring to the Malvern Hills?] and other more common species.
The total lichen flora of Worcestershire is 228 species and
varieties and the following are some of the more rare, not recorded in the
foregoing notes: -
|Leptogium sinuatum, Huds||(Leptogium gelatinosum)|
|-- turigidum, Ach||(L. turigidum)|
|--Schraderi, Bernh.||(L. schraderi)|
|Conicybe furfuracea, Ach||(Chaenotheca furfuracea)|
|Alectoria jubata, Linn.||(Bryoria fuscescens)|
|Peltigera rufescens, Hoffm||(Peltigera praetextata)|
|Parmelia fuligenosa, Dub.||(Melanelia fuligenosa fuligenosa)|
|Parmelia conspersa, Ehrh.||(Xanthoparmelia conspersa)|
|-- acetabulum, Neck, Vahl.||(Psoroma hypnorum )|
|Placodium citrinum Ach.||(Caloplaca citrina)|
|--candicans, Dicks.||(Solenopsora candicans)|
|Lecanora tartarea, Linn.||(Ochrolechia tartarea or O. androgyna)|
|--circinata, Pers.||(Aspicilia radiosa)|
|Lecanora epixantha, Ach.||(Candelariella aurella )|
|Lecidea lucida, Ach.||(Psilolechia lucida)|
|-- canescens, Dicks||(Diploicia canescens)|
|-- ehrhartina, Ach||(Cliostomum corrugatum )|
|-- tantilla, Nyl. (?)||[synonym not yet determined]|
|Graphis dendritica, Ach.||(Phaeographis dendritica)|
My principal authorities for the foregoing notes are Mr. E
Lees’ Botany of Worcestershire and Malvern; and Dr. Holl’s records in
Leighton’s Lichen Flora of Great Britain, Ireland and the Channel Islands,
3rd edition, 1879.
Comments on the 1901 Lichen Flora of Worcestershire Notes
This compilation of lichen records gathered 125 years ago have come from a number of sources. Unfortunately there is little information on site details, habitats, recording dates, or recorder identity. I am currently examining the lichen collection held at Worcester Museum and I hope to retrieve some of this valuable additional information.
Lichen longevity and their sensitivity to pollutants has been known for some time. Nowadays, they are accepted as sensitive biological indicators – they are nature’s equivalent to the coal-miner’s canaries. Lichen classification has always been problematical and at one time thought there was a parasitic relationship between the algae and its fungal associate. It is now accepted that a lichen is the result of a symbiotic association between a photobiont (an algae and /or a cyanobacteria) and a mycobiont.
The account clearly identifies lichen distribution through out the county including the lichen deserts in large towns. The harmful effects of the atmospheric pollutant sulphur dioxide, a by-product, caused these from the burning coal for domestic and industrial purposes.
Lichens are rather inconspicuous and easily overlooked. I suspect that the author of this 1901 account was a little over-enthusiastic in his descriptions of “lichen abundance”. Nevertheless he draws attention to the lichen flora found at that time on walls, trees and bridge coping stones. Some of these bridges are still standing, for example, at Lower Wick and Pershore, and still support a varied crustose lichen flora.
Worcestershire’s Lichen Flora 2005
During the last hundred years there have been many changes both locally and nationally. Air qualities are different; land use and farming practices have also changed. Some habitats are either lost or significantly reduced. For example many of our traditionally managed orchards have been grubbed up, hedgerows removed, wet lands drained, and, many woodlands were of necessity clear-felled during the two World Wars. Conversely, other new habitats have been created, such as new towns and their infrastructures, garden hedges, pavements, walls, new buildings, woodlands etc.
Sulphur dioxide pollution levels continued to rise during the twentieth century, peaking in the 1950’s. Following the introduction of the Clean Air Acts in the 1960s the pollutant has declined and followed, sometimes many years later, by lichen re-colonisation. The present day pattern of lichen distribution is similar to that described in the 1901 account with some modifications. The lichen deserts in the large towns have either been eliminated or significantly reduced but the absence of the extremely sensitive species continues. Re-colonisation, it has been found, does not follow in an orderly reverse sequence i.e. the last species lost is the first to re-colonise. It is thought that some species exhibit poor re-colonisation abilities whereas others prove that dispersal efficiency is of greater importance rather than their sensitivity to the environment.
The Malvern Hills is still a lichen-rich area with abundant and varied saxicolous species on the native outcrops found on the North Hill and the Worcestershire Beacon. Malvern’s corticolous species are rather more diverse and best seen on the veteran trees on the southern end of the hill chain. Other lichen rich habitats are the veteran and mature woodlands in the deeper Teme Valley dingles; the walls, memorials and churchyards surrounding the south foot of Bredon Hill; sandstone outcrops at Habberley Valley; the sandy heaths at Devils Spittleful and the mature oaks in Spetchley Deer Park. Happily for us, the area known as Paradise in Lower Sapey, is still a lichenological paradise.
Present day records have been taken from Greater Worcestershire, where churchyards are prime sites for lichen recording. Other habitats include veteran trees, listed buildings, private gardens, recreational parklands, deer parks, common lands, traditionally managed orchards, orchard remnants in urban gardens, nature reserves, the Malvern Hills, Bredon Hill, Habberley Valley, Devils Spittleful, large areas of the Wyre Forest and Hartlebury Common. Every record taken has been annotated with a 6-figure grid reference, and copies deposited both locally and nationally.
The pollutant now causing some concern are those linked to nutrient enrichment. Physcian and Xanthorian communities flourish, often flamboyantly in this environment. Other lichen species, unable to tolerate this pollutant, are in decline; for example, Parmelia saxatilis previously a common lichen is in decline, and conversely, Parmelia sulcata hardly known 150 years ago is now ubiquitous. There are no simple answers to explain precisely why the flora is changing. It may be many years before this is fully understood and in the meanwhile confirms the importance of taking and keeping accurate records.
Our present Worcestershire lichen flora has approximately 340 species. Some
of today’s species were not identified in 1879 and others, recorded by Lees
and Holls, are unknown to us. The more exotic species such as Teloschistes
flavicans, Byroria fuscescens and Lobaria pulmonaria can only
survive where harmful air pollutant levels are extremely low. These species have
long since been lost in Worcestershire. Other species listed in the 1901 account
have not yet been found and may also be lost. They include:
Bundophoron melanocarpon, Sphaerophorus fragilis, Parmelia omphalodes, Caloplaca ferruginea, Massalongia carnosa, Catapyrenium cinereum, Collema nigrescens, Trachylea tigillaris, Psoroma hypnorum, Aspicilia radiosa, Cliostomum corrugatum, and Phaeographis dendritica.
Some of our present day rarer lichens include:
Acarospora glaucocarpa Malvern Reservoir
Bacidea rubella Grafton Wood
Caloplaca cerina Spetchley Park
Catinaria atropurpurea Grafton Wood
Candelaria concolor Kemerton Nature Reserve
Chaenotheca furfuracea Holly Bush Hill
Cresponea premnea Spetchley Deer Park
Dermatocarpon miniatum Broadway Churchyard
Enterographa crassa Teme Valley Ash trees
Gyalecta jenensis Feckenham Church
Lecanora carpinea Bodenham Arboretum
Lecanora epanora Malvern, North Hill outcrops
Leptogium turgidum Kemerton Churchyards
Opegrapha ochrocheila Pershore, Rough Hill Orchard
Opegrapha vermicellifera Kemmerton Orchard
Peltigera praetextata Teme Valley
Physcia stellaris Spetchley Estate
Protoblastenia calva Welland Church
Pyrenula chlorospila Ash trees in the Teme Valley dingles
Rinodina exigua Spetchley Estate
Stereocaulon evolutum Habberley Valley outcrops
Thelidium incavatum Stoke Prior Church
Tuckermannopsis chlorophylla Malvern, Hollybush Hill
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