Part 68

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.

(iii) Fungi of bogs and marshes

(a) Sphagnum bogs

~Hypholoma elongatum~ (Fries) Ricken

Cap: width 12-20 mm. Stem: width 3-5 mm; length 50-80 mm.

Description: Plate 75.

Cap: bell-shaped but rapidly expanding to become plane, honey-yellow with a greyish green tint, slightly striate at the margin and also with a few remnants of a fibrillose veil when very young, but these are soon lost.

Stem: slender, smooth, whitish at the apex and yellow-brown or honey-yellow below.

Gills: adnate and distant, pale ochraceous honey-yellow then lilaceous grey and finally sepia.

Flesh: yellowish in the cap, red-brown in the stem and lacking a distinct smell.

Spore-print: purplish brown.

Spores: long, ellipsoid, fairly thick-walled, olivaceous brown under the microscope and with a small germ-pore, smooth and 10-12 × 6-7 µm in size.

Marginal cystidia: flask-shaped and hyaline.

Facial cystidia: flask-shaped with contents which turn yellowish in solutions containing ammonia.

General Information: This fungus which appears from early summer to late autumn is recognised by the almost uniform ochraceous colour with hint of olive and its habit of growing in troops. The word elongatum means elongated and refers to the shape of the stem which pushes up through the Sphagnum and in order to disperse its spores it must elongate so that it just pushes up above the bog-surface. H. polytrichi is closely related to H. elongatum but has a paler cap and stem and it grows in moss, particularly Polytrichum in woodlands; the spores of H. polytrichi are paler, slightly narrower and slightly thinner, but they have a much more distinct germ-pore.

Both the above species have been formerly placed in Psilocybe, but they are more correctly classified in Hypholoma along with the sulphur-tuft fungus (see p. 64) because of the cortina-like veil and specialised facial cystidia.

Illustrations: WD 78⁵.

~Tephrocybe palustris~ (Peck) Donk

Cap: width 12-30 mm. Stem: width 3-5 mm; length 50-75 mm.

Description: Plate 75.

Cap: bell-shaped then plane-convex, but finally depressed at centre, watery buff to greyish with flush of ochre or smoky grey, striate to centre when moist, but drying out non-striate and uniformly ochraceous buff.

Stem: thin, rather long, smooth, similarly coloured to the cap or paler, fragile and whitish woolly at the base.

Gills: dirty whitish, adnate with a tooth and not very crowded.