Llanelli Naturalists Newsletter - March 2000 - No 65
Before commenting on the truffle species recorded from South Wales, we might first consider what truffles are. When truffles are mentioned the first thing one thinks of is food. Certainly, the Périgord truffle Tuber melanosporum is the most highly prized culinary truffle but unfortunately not found in this country. The Summer Truffle T. aestivum is a good edible species occurring mainly in beech woods on chalky soil in southern England.
One must not think of truffles as just the few edible species but as specialised fungi from the three main subdivisions of the Kingdom Fungi, namely Zygomycotina, Ascomycotina (cup fungi and their allies) and Basidiomycotina (Agaricales and several other orders of what we generally understand as ‘mushrooms’). Truffles of Zygomycotina are known as ‘Pea-truffles’, those of Ascomycotina as 'Truetruffles and of Basidiomycotina as ‘False-truffles’.
These fungi have evolved a means of living underground (subterranean or hypogeous), retaining their spore producing function but dispensing with structures we commonly associate with toadstools. All hypogeous fungi, Pea, False or True-truffles, have a rounded or oval form originating and remaining underground, although a few may be found in leaf litter or near the soil surface. They have no special mechanism for spore dispersal but spores are disseminated by the natural breakdown of the fruit body or these are eaten by insects and small mammals. Hypogeous fungi are frequently associated with trees, forming a close association with tree roots (mycorrhizal association) and the host tree is often specific to the fungus species.
About 80 species of hypogeous fungi have been recorded in Britain. Most of these were described between 1846 and 1875 by the Rev. J.M. Berkley and C.E. Broome, Broome being mainly responsible for the field work in the Bristol area. It was not until almost 100 years later that Professor Lilian Hawker undertook further detailed studies of truffles, again mainly in the Bristol region, and published a monograph (1954) British Hypogeous Fungi. In 1993, the Royal Botanic Gardens, Kew, published British Truffles by D.N. Pegler, B.M. Spooner and T.W.K. Young, a revised account of truffle species found in Britain and listing all substantiated records. It is from this book that most information for this article has been obtained.
This publication was not available in May 1978 when during a Llanelli Naturalists field meeting at Ystradfellte waterfalls, I put my hand on a truffle while sitting on the ground under an oak tree, having lunch. The specimen was not sent to Kew and unfortunately never identified. The next truffle I collected was under Cupressus in Pembrey Forest in July 1985 and identified by Kew as Strong-Scented Stephensia Stephensia bombyacina. This species is one of the true truffles and occurs on the surface layer of soil or leaf litter. A second truffle collected from Pembrey was found by Emma Chin during the annual Pembrey Country Park foray in October 1996. This truffle, Blushing Beard Truffle Rhizopogon roseolus, was found on the soil surface at the edge of a path and under Pinus, with which it is always associated. It seems that this species is generally found more deeply buried than other related species, up to 8 cm deep. This is one of the ‘false truffles’.
Both the Rough-coated Elaphomyces Elaphomyces muricatus and Harts Truffle E. granulatus were found at Pengelli Forest, near Newport, Pembs. in May 1987 during the British Mycological Society foray held that year at Fishguard. These are true truffles and among the most widespread and most frequently collected truffle species. This may be because these species are often parasitised by species of Cordyceps, another fungus, whose fruit body is relatively conspicuous on the soil surface or showing through moss. Other species of Cordyceps parasitise moth larvae and flies.
The only other truffle recorded from South Wales is the Lemon Pachyphloeus Pachyphloeus citrinus, another true truffle. This species is very rare in Britain. This collection was made in October 1847 and there are no confirmed finds from Britain since 1848. A collection from the Bristol area in 1951 could not be positively identified as this species because the specimen was immature and spores not properly developed. The 1847 find was made at Penllergaer, near Swansea, and the specimen is still at Kew having been in the herbarium of C.E. Broome. At this time, the large house at Penllergaer (since demolished and replaced by council offices) was the home of John Dillwyn Llewelyn, related by marriage to Willian Henry Fox Talbot the photographic pioneer. Llewelyn was an enthusiastic photographer himself and his father, Lewis Weston Dillwyn, is reputed to be one of the founding fathers of botany and zoology in this country and
Swansea and the Neighbourhood’ in 1848 (title page illustrated below). With this connection one can understand how Broome came to acquire and identify the Penllergaer specimen. In 1998, the Glyn Vivian Art Gallery, Swansea, held a splendid exhibition of images from John Dillwyn Llewelyn’s photographic album entitled ‘Sun Pictures’. One of these photographs showed a daughter of Llewelyn’s looking down a microscope. With only 5 out of 80 truffle species having been recorded from the South Wales area, there is clearly much scope for adding to this list. Anyone who picks up a small pebble-like object that is not a stone, plastic, polystyrene or wood, might pass it on to me in case it is a truffle. But please note location and if under a particular type of tree. A future article could describe the various ways truffle hunters set about their task....................get your rakes ready!