(ii) Fungi of bonfire-sites

Pholiota highlandensis (Peck) A. H. Smith Charcoal pholiota

Cap: width 20-50 mm. Stem: width 4-8 mm; length 25-60 mm.

Description: Plate 73.

Cap: convex then flattened and slightly umbonate, smooth, very sticky at first, but becoming shiny when dry, orange-yellow to sand-colour; the margin is first incurved and ornamented with filaments from the veil, but these are soon lost.

Stem: dirty yellow, darker towards the base, cylindric or narrowed downwards and covered in small fibrillose scales.

Gills: clay-coloured then dull brown, adnate and crowded.

Flesh: yellowish.

Spore-print: dull rust-brown.

Spores: medium-sized, ellipsoid, smooth, dull brown under the microscope and 7-8 × 3-4 µm in size.

Facial cystidia: spindle-shaped with obtuse apex.

Marginal cystidia: similar to facial cystidia but usually smaller.

General Information: This fungus which occurs from spring to autumn is recognised by the habitat, colour of the fruit-body and the spore-size. It is known in many books as Flammula carbonaria (Fries) Kummer, but the genus Flammula is no longer used for it refers to a flowering plant in the buttercup family.

P. highlandensis is the same fungus as that referred to as Pholiota carbonaria by European Mycologists, but this name cannot be used for it refers to an entirely different N. American species. ‘Highlandensis’, in fact, refers to the locality where the present fungus was first found in the United States of America. The true P. carbonaria A. H. Smith has only been found once in Europe and this only recently in the south of England. It differs in the reddish orange scales on the stem; indeed it is a much brighter fungus than the common charcoal Pholiota.

Tephrocybe anthracophila (Lasch) P. D. Orton

Cap: width 1-4 mm. Stem: width 1 mm; length 2-5 mm.

Description: Plate 73.

Cap: blackish when wet, drying sooty brown, slightly depressed in the centre, smooth, and viscid.

Stem: sooty brown, tough and smooth.

Flesh: sooty brown.

Gills: whitish then grey, adnate and not very crowded.

Spores: medium sized, subglobose, 4-6 × 4-5 µm in diameter and minutely roughened.

Spore-print: white, not blueing in solutions of iodine.

General Information: T. atrata also grows on burnt soil and is very closely related, but differs in its spores being broadly ellipsoid and smooth. Mycena leucogala also grows on burnt soil (see p. 88).

Illustrations: T. anthracophila—LH 83. T. atrata—WD 4^b.

Psathyrella pennata (Fries) Pearson & Dennis Bonfire brittle-cap

Cap: width 10-30 mm. Stem: width 1-3 mm; length 30-40 mm.

Description:

Cap: conical or bell-shaped then expanding and slightly umbonate, whitish because of a coating of dense fibrils, but soon becoming brownish as these are lost.

Stem: short, stout, white and densely floccose.

Gills: slightly adnate, pale brownish grey with pink tinge, then dark-brown.

Spore-print: purplish brown.

Spores: medium sized, oval, ellipsoid with an obvious germ-pore, purplish brown under the microscope and 8-9 × 4-5 µm in size.

Marginal & facial cystidia: flask-shaped, hyaline with either a short or long neck.

The brown-spored Hebeloma anthracophila Maire is similar.

Coprinus angulatus Peck Bonfire ink-cap

Cap: width 4-25 mm. Stem: 1-3 mm; length 15-30 mm.

Description:

Cap: dark red-brown at first, then orange-brown, especially at the margin and appearing as if frosted all over, conical at first but rapidly expanding at the margin and becoming grey-brown, strongly striate and deliquescent, leaving finally only a central red-brown umbo.

Stem: white and minutely hairy.

Gills: free, dirty whitish then black.

Spore-print: black-brown.

Spores: medium sized, dark brown under the microscope, lobed like the hat of a bishop and 8-11 × 6-8 × 5-7 µm in size.

Marginal cystidia: bottle-shaped, very variable.

Facial cystidia: similar to marginal cystidia.

General Information: It must be noted that this fungus has spores which require three quite different measurements to describe the dimension. Another species of Coprinus found on burnt soil is C. lagopides Karsten which resembles C. cinereus (Fries) S. F. Gray (p. 211); it is typified, however, by the rounded spores.

General notes on fungi of burnt sites

Several common fungi found at the sites of bonfires have their closest relatives amongst various groups of microscopic fungi more than amongst the large forms already discussed. Keeping a close watch at the site of a former bonfire day by day, week by week and month by month is very rewarding and shows a further example, like the dung habitat, of a tightly knit community of various groups of fungi.

Peziza repanda Persoon has been discussed in detail above (p. 200); its close relatives P. petersii Berkeley & Curtis (brown with grey tints and with spores finely warted and measuring 10-12 × 5-6 µm), P. praetervisa Bresadola (violet or mauve and with spores finely warted and measuring 11-13 × 6-8 µm), P. violacea Persoon (dark violet with smooth spores measuring 13-15 × 7-9 µm) and P. echinospora Karsten (dark chocolate brown with spores densely warted and 14-18 × 7-10 µm in size) all grow on the sites of old bonfires or around charred root stumps. Rhizina undulata also found by charred stumps has been described on p. 203. These are large to medium sized disc-fungi, but there are many much smaller species which cannot be dealt with here, such as species of Anthracobia and Trichophaea. Pyrenomycetes are also found on charred wood and soil. Probably the commonest species of fungus met with is a pale reddish orange to rose-pink disc-fungus seated on a white mycelial mat; this is Pyronema omphalodes (St Amans) Fuckel. Morchella esculenta St Amans and M. elata Fries (see p. 200) appear to grow on the sites of garden bonfires or where cinders have been spread on the soil surface. The stimulus for fruiting appears to be due to the release of mineral nutrients during the process of burning. Competition from other fungi appears to be reduced so rapid colonisation by the bonfire fungi (carbonicoles) after the period of sterilisation ensures their development. Many similar fungi were found about bomb- and shell-craters on the continent during the two World Wars.

One microscope fungus, however, must be mentioned when considering bonfires and that is Neurospora sitophila Shear & Dodge so much used in genetical studies. It can be found as the conidial state on burnt soil and is called ‘Baker’s mould’ because it is frequently found growing on refuse in the hot moist conditions of bakers’ kitchens.