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Extracted from Transactions of Hertfordshire Natural History Society 33(3) 273-280 , 1998, by kind permission of the author.
Gobions Wood (TL250035) and its associated habitats comprise an extensive site in the south of Hertfordshire occupying a shallow valley in the parish of North Mymms between Brookmans Park and Potters Bar. The site as considered here includes Gobions Open Space, Gobions Pond, the former Gobions Gardens as well as relatively unimproved acid/neutral grassland and the main area of woodland.
The site comprises a diverse range of habitats, soil types, aspects and drainage conditions with a varied history of land use. Geologically much of the site is on the Reading Beds but with London Clay beneath the eastern end. Although partially modified by landscaping, much of the woodland is ancient and has probably been wooded for many centuries.
The area of ancient semi-natural woodland comprises an interesting and diverse range of higher plant species. Most of the eastern part of the woodland and part of the north side was Hornbeam wood managed as coppice in the past it is now high forest. There are some large hornbeam standards as well as Oak and Ash. The western end is mainly Sycamore with some Ash and Corsican Pine. Suckering Elms have colonised in places. [Most of] the former Gobions Garden area is now also woodland, but in addition to the differences in ground flora which reflect its more recent origin, there is evidence of the former landscaping with planting of Rhododendron and exotic conifers such as Coast Redwood (Sequoia sempervirens) and Wellingtonia (Sequoiadendron giganteum).
The ground flora of the ancient woodland includes abundant Bluebells, Dogs Mercury (Mercurialis perennis) and Wood Anemone (Anemone nemorosa) together with Moschatel (Adoxa moschatellina), Wood Sorrel (Oxalis acetosella) and a number of County rarities.
Further variety at the site is added by unimproved pastures, ponds, scrub and hedgerows. The site is of very considerable importance for a diverse range of organisms including Bats, Reptiles, Invertebrates, Higher Plants and Fungi.
The first known mycological records from the site comprise just three species noted by Peter Holland in September 1976. On 26 October 1988 the site was visited by Margaret Holden and Patricia Baker who recorded 79 species. The first organised foray to the site was the Berkhamsted WEA Fungus Group Foray on 18 October 1992 led by the present author when 186 species were noted. Since then the site has been visited annually for organised forays of the Berkhamsted WEA Fungus Group together with several out-of-season visits by this group. There have also been many private visits mostly by Kerry Robinson and Alan Outen. In total over 30 visits have been made to the site to record fungi since 1992 with at least one visit in every month of the year and with April, September and October each having received 6 visits.
The site consistently produces long lists of species as is shown below in the table below of number of species recorded on organised forays for the period 1992-97:
This represents an average foray score for the six organised forays in the autumn season between 1992 and 1997 of 178 species. It should also be borne in mind that throughout much of this period the County (and indeed the Country) was experiencing drought conditions. Few other Hertfordshire sites were consistently producing lists of this magnitude.
It is also perhaps worth noting that even organised excursions outside the main season have proved extremely productive as for example the winter visit of 5 Dec 93 and the spring foray of 24 April 94 which produced 100 and 79 species respectively while a private visit by Kerry & Pat Robinson on 28 September 1994 yielded 130 species.
The total of 243 species recorded at this site on the foray of 26 September 1993 represents the longest ever day foray list for Hertfordshire. This comfortably exceeds the previous best for the County of 208, a similar total to the largest day foray score ever recorded in Bedfordshire by the Bedfordshire Natural History Society, on forays led by Dr D.A. Reid (County Recorder for Fungi in Bedfordshire for over 40 years, and formerly Head of Mycology at Royal Botanic Gardens Kew).
In the comparatively short time that the Gobions site has been studied mycologically it has not only produced big foray scores but the overall diversity for the site is impressive as can be seen by comparing the number of recorded species in various groups with Bricket Wood, widely acknowledged as an important mycological site and one which has been studied for over 100 years (Holden & Outen 1989).
N.B. The statistics for Bricket Wood have been updated since (Holden & Outen 1989).
Note that the records for Gobions represent only six autumn seasons in contrast to Bricket Wood for which records exist for over 100 years, with particularly intensive study over the 18 year period 1970 - 87. Over a longer period of study the list for Gobions will inevitably increase considerably. It can take very many years of recording to produce a list of Fungi for a site which is anywhere near comprehensive. Even after over 100 years of recording at Bricket Wood new species continue to be added to the list.
It is apparent already however that this is a site with a very diverse mycoflora. In addition, although the overall site considered here is 92.8 hectares the principal interest lies within a much smaller area than that of Bricket Wood (which totals approx. 70 hectares if one includes all the original common and land currently within the SSSI).
The importance of Gobions as a site for Aphyllophorales, Heterobasidiomycetes, Ascomycetes and other microfungi is clearly apparent from the table. True toadstools and Gasteromycetes, which are fleshy and relatively short lived, tend to be much more seasonal in the appearance of their fruit bodies than the more persistent bracket fungi and the fruiting of the fleshy types is also more susceptible to vagaries in weather conditions. A range of Ascomycete species and other microfungi can be found at different times of the year. The presence of large amounts of dead wood also favours these groups in contrast to Bricket Wood where relatively few species have been found in association with dead wood.
The importance of dead wood at this site is also evident from the occurrence of no fewer than 14 species of the toadstool genus Pluteus which principally occur on dead timber, whereas only 5 species of this genus have been found at Bricket Wood.
In contrast, comparatively few species have as yet been found at Gobions of the large fleshy terrestrial toadstools of the genera Amanita, Russula, Lactarius and no species of Tricholoma have so far been recorded. Only 5 Boleti have been noted (four of these are in the genus Xerocomus, while Leccinum carpini recorded in 1987 represents a new record for the County). A comparison between this site and Bricket Wood is again interesting:
In fact the contrast between the two sites in this respect is even more marked than it appears since at Bricket Wood (as with other sites of established mycological importance in the County such as Ashridge, Sherrardspark Wood, Whippendell Woods, etc.) species of Amanita, Lactarius, Russula and Boleti often produce abundant fruit bodies whereas those species which do occur at Gobions are relatively scarce in numbers. This is in part due to the mix of tree species present since few members of these genera associate with Hornbeam, Ash, Elm or Sycamore which are among the most numerous trees at the site. It is significant that Leccinum carpini (mentioned above) is one of the few Boleti which may be found in association with Hornbeam. Lactarius circellatus is one of the commoner members of this genus at Gobions and is another Hornbeam speciality (It is consequently a species common in Hertfordshire but not recorded for neighbouring Bedfordshire). Some Lactarius species normally associated with Beech, such as L.blennius and L.subdulcis may occasionally grow with Hornbeam as indeed they do here.
The rich diversity of the Fungus flora of this site is by no means the only reason for its importance for no other Hertfordshire site can boast so many rare and unusual species and the site continues to produce new, exciting and interesting finds on a regular basis. Two species have been recorded from the site as new to Britain:
Ing (1992) produced a provisional red data list of British Fungi though this was severely criticised by Orton (1994) who comments that some of the species included are not officially on the British list. The inclusion of some other species, particularly those with restricted distributions, is also questionable. It is equally the case that some species for which only a few British localities are known have not always been included.
In Ing's Provisional Red Data List for British Fungi the following four categories are used:
Extinct or possibly so, Endangered, Vulnerable and Rare. Species included in the Provisional Red Data List which are recorded from Gobions are given below together with the categories used by Ing in parenthesis:
The resupinate polypore Gelatoporia pannocincta was not recorded in Britain until 1990 when it was found in the New Forest Hampshire. The second British record was by Paul Cook on the Hertfordshire Natural History Society foray to Panshanger in 1991. It was found at Gobions Wood on the underside of a fallen log by the water by Kerry Robinson on 28 September 1994 as the second record for the County and still only the third British site.
Although not included in the Provisional Red Data List there are only a handful of British collections of Lindtneria leucobryophylla at the national herbarium at Kew. Kerry Robinson made the first British find of this for 40 years in Baldock in 1993 and followed it with collections at Banfield Wood near Benington in 1994 (Robinson 1995) and Gobions on 10 November 1996. Most British collections appear to be between November and March.
Another species for which the status is unknown in Britain is Clitocybe truncicola as the species was only described in 1988 (Orton 1988), though a number of Hertfordshire sites are now known. This species, which was first found here in 1988 and then again in 1995, is unusual in the genus in growing on wood. There are few British records and only three Hertfordshire collections of the distinctive Clitocybe houghtonii found at Gobions in October 1988.
As indicated above Mitrula sclerotipus is given as rare in the Provisional Red Data List. Brian Spooner, the Ascomycete specialist at Royal Botanic Gardens Kew, reports never having previously seen fresh material of this species. It had been suspected that this species was parasitic on the sclerotia of the fairy club Typhula phaccorhiza. This collection seems to confirm this as the two species were found here growing together in October 1992.
Many other species are given in the literature as rare in Britain although authors vary widely in their interpretation of this. Three toadstool species recorded here which are sometimes claimed to be nationally rare are Agaricus bohusii, Lentinellus vulpinus, Psathyrella multipedata.
Other species of significance here include the uncommon corticioid Hyphoderma cristulatum. Kerry Robinson reports her find of this species at this site on 29 January 1995 in these Transactions (Robinson 1997) while Leucogyraphana mollusca was another of Kerry Robinson's finds here collected on 23 October 1994 (Robinson 1995). The occurrence here of four species of Tomentella is also worthy of mention.
The cup fungus Miladina lecithina is also of significance based on the number of national collections while the Slime Mould Trichia lutescens was recorded here in by Kerry Robinson in December 1993. P Holland, an authority on British Myxomycetes with long experience, considers this species as rare in Britain and reports seeing it only very rarely.
In addition to the species referred to above it is quite remarkable that in excess of a further hundred of the species recorded from this site are otherwise rare or scarce in Hertfordshire.
Checklist of species recorded for Gobions Wood area click here
This site is proving to be one of the most important for Fungi in the County. There are a number of contributory factors to this, including the large amounts of highly productive dead timber, the uneven terrain, the damp conditions and the diverse higher plant flora, including species which are rich hosts for microfungi. Other Counties in Britain already have Sites of Special Scientific Interest designated on the strength of their mycological importance, some with far weaker credentials than Gobions. If any site in Hertfordshire deserves such status for its Fungi then surely this one does while the added importance of the place for other organisms further strengthens this claim. It is important that future management work should take account of the mycological interest and importance of this site.
I am grateful to all those who have supplied records for this site and especially Miss Kerry Robinson for all her data. The continued co-operation of the Gobions Woodland Trust, and in particular Mr Michael Jonas in permitting the recording of Fungi at this site is greatly appreciated.
The generous assistance of Dr J Cooper, Mr A.Henrici, Mr E.Holland, Dr T.Laessoe, Dr D.A.Reid, Dr B.Spooner and Dr Ulje in identification/confirmation of critical species is gratefully acknowledged.
Holden M. & Outen A.R. (1989) One Hundred Years of Bricket Wood Fungus Records Transactions of Hertfordshire Natural History Society 30 (3) 227-243
Ing B. (1992) A provisional red data list of British Fungi Mycologist 6 (3) 124-128
Marshall I. (1987) Gobions Wood Ecological Appraisal (unpublished manuscript)
Orton P.D. (1988) Notes on British Agarics IX Transactions of British Mycological Society 91 (4) 545-571
Orton P.D. (1994) Some comments on "A Provisional Red Data List of British Fungi" by B.Ing Mycologist 8 (2) 66-67
Reid D.A. (1995) Coprinus nemoralis Bender, new to Britain Mycologist 9 (3) 119-120
Robinson K. (1995) Some Resupinate Fungi from Hertfordshire Mycologist 9 (3) 135-137
Robinson K. (1997) Interesting Fungus Records 1995-6 Transactions of Hertfordshire Natural History Society 33 (1) 35-39