Caithness Field Club

Some Common Caithness Toadstools & Their Uses

Most people think they can tell the difference between a mushroom and a toadstool: a mushroom is edible, whereas a toadstool is said to be deadly poisonous. Nothing could be more wrong; a mushroom is a toadstool and nearly all toadstools are not poisonous.

Despite the many old wives' tales for distinguishing between edible and poisonous toadstools, there is only one method for distinguishing the poisonous ones: identification of the toadstool using a reliable identification guide.

One of the first fungi to appear in the spring in Caithness is the "St. George's Mushroom" Tricholoma gambosum. This species is found in grassy places and seems to prefer the calcareous pastures around Dunnet Bay, Sinclair's Bay and the Sandside area. It can be found from April until about July and it is an edible species. Because there are very few other fungi around in the early part of the year, it is particularly easy to identify. It has a creamy white cap and stipe (stem) with white crowded gills and has a strong meally smell and taste. In some years they thickly carpet the grass around Castlehill and large numbers can be collected for the freezer.

Another very common species in the Tricholoma genus to be found in Caithness are the "Blewits". Tricholoma saevum is known as the "field blewit" and Tricholoma nudum as the "wood blewit". The latter species is adapting itself to the new Forestry Commission plantations and is particularly common in Dunnet Forest from September until severe frosts kill it off. The whole toadstool is a lilac or violet colour and the cap is up to 10cm diameter. The similar field blewit has a bluish stem (or stipe) covered with violet scales, but the cap is a clay colour and the flesh white. In some years this species can be particularly common in the fields around Dunnet and Castletown and inland from Sinclair's Bay from September to December. Both species are edible and are especially wholesome when stewed in milk with a small knob of butter and thickened with cornflour. In a few areas of Great Britain the field blewit is sold on the open market where it is more expensive to buy than the cultivated mushroom.

An easily identifiable genus which will spread rapidly in Caithness now that more tree-planting is taking place is the genus Russula. All the species have brittle gills that break and the flesh is granular. There are about seventy species of Russula but they are extremely difficult to separate into species, even for an export. None of them are poisonous when cooked, but many are unpalatable due to their bitter taste. Many of the species are highly coloured, the red coloured species being particularly common in the Forestry Commission plantations.

A similar genus to the Russula is the Lactarious which also has brittle gills. This genus can be easily distinguished from the Russulas by the milky fluid that flows from the broken stem and, for this reason, the genus is often known as "milky caps". There are two very common members of this genus in Forestry Commission plantations: Lactarius rufus, a dull reddish-brown fungus containing a very acrid milky fluid which causes it to be inedible, although not actually poisonous; and Lactarius deliciosus which has a reddish-orange cap with a series of rings on the cap; this is even more common under conifers in Caithness. It can easily be distinguished from Lactarius rufus by the mild taste of the milk, which rapidly turns a carrot colour. When the fungus becomes old, it takes on a green appearance. It is an edible species but old green specimens should be avoided.

Deciduous trees have their own species of fungi. A very common fungus found growing on deciduous trees all over Caithness is F1ammulina velutipes. This species is found growing on stumps, trunks and branches and even manages to invade branches of broom. The cap is yellow ochre and it has a dark brown velvety stipe. Most identification books indicate that the cap size may be up to 6cm diameter, but in Caithness it rarely exceeds 2cm. Good specimens are to be found in the old trees around Braal Castle and at Castlehill. Small specimens can be found amongst almost any patch of old broom from November until about March. The caps of this fungus are edible, but the stipes are tough and should preferably be discarded.

The Boletaceae are a small family of toadstools differing from other toadstools in the way that the underneath of the cap is covered with a large number of pores instead of gills. Many species of Boletus can be found in deciduous and coniferous woods in Caithness and a sharp look out should be kept for the cep (Goletus edulis) which is highly-prized throughout Europe as a fungus with an excellent taste. This species has a white bun-shaped cap with a massive stipe which swells towards the base. Boletus granulatus, which has a slimy Cap and Boletus variegatus are both common in our coniferous woods and, although they are not poisonous, they have little taste. There are no deadly species of Boletus, but Boletus satanus will cause vomiting if eaten raw; fortunately this grows under deciduous trees on calcareous soils and does not appear to be present in Caithness.

Most dung heaps contain a good selection of fungi and the "ink caps" genus Coprinus can become very common in such places. This genus is characterised by the cap deliquescing or dissolving away when the spores on the gills are ripe. A specimen collected during a walk can very rapidly turn into a black mess and look very unappetising. Most members of this genus are too small to eat and their habit of growing on dung does not make them appetising. One member of the family which does not usually inhabit dung heaps is the Lawyer's Wig or Shaggy Cap, Coprinus comatus. This is easily recognised by its cap which is in the form of a narrow cone covered with shaggy woolly scales. Specimens up to 25cm in height have been found, but they are usually much smaller in Caithness.

This is an excellent fungus to eat, but it should be collected when young before the cap starts to digest itself. The species seem to prefer roadsides. For alcoholics, Coprinus atramentarius is recommended. This species, which even makes its appearance in Caithness gardens, will cause severe nausea if eaten at the same time as alcohol and it has been used as a treatment for this disease. For non-alcoholics it is an edible but not very interesting source of food.

The genus Hygrophorus is very common throughout the district and can be identified by its thick distinct gills which feel waxy. All members of the genus are edible but very few of them are worth eating. Hygrophorus puniceus is very common in grassy places and has a blood-red cap which soon fades. It helps to pad out a fungus stew but on its own it is tasteless.

Most Caithness country people know what the field mushroom (Agaricus campestris) looks like. It is very common in pastures throughout the district. Few people are aware of its close relative the yellow staining mushroom, Agaricus xanthodermus, which can cause coma, vomiting and diarrhoea. If the base of the stipe turns bright yellow on cutting, then Agaricus xanthodermus should be suspected. Although it is not common, one specimen can cause alarming symptoms, but fortunately recovery will take place within a few days.

There are many thousands of different fungi, as many as a hundred thousand according to some authorities. Identification is very difficult and there are large areas where knowledge is very sparse. Nobody can hope to be able to identify all of them, but with a little bit of time and patience it should be possible to identify the more common ones and help to build up a list of species present in Caithness

he following easily obtainable reference books should help to identify many of the common species:

Collins Guide to Mushrooms and Toadstools by Morten Lange and Bayard Hora.
New Field Guide to Fungi by E. Soothill and A. Fairhurst
Wayside and Woodland Fungi by W. Findlay.

Published in 1981 April Bulletin