instead of referring all the pored, fleshy fungi to a single large genus
several genera are now recognised. The separation of these genera is
based on differences in colour of the spore-print and differences in the
anatomy of the tubes, cap and stem, etc., e.g. members of the genus
_Suillus_ have colourless or pale coloured dots on the stem exuding a
resin-like liquid in wet weather, which is clear and glistening in some
species but turbid and whitish in others, gradually darkening and
hardening so that the stem is ultimately covered in dark brown or
reddish smears or spots; members of the genus _Leccinum_ on the other
hand never exude liquid and have coarse or fine roughenings on the stem
which are usually dark, but may commence white and ultimately darken
depending on the species; many species of _Boletus_ possess a very
distinct raised network all over the stem, whilst others have it present
only in part, or have minute, often brightly coloured, dots replacing
it.
[Illustration: Plate 3. Fleshy fungi: Spores borne within tubes]
Within this single, yet not particularly large, group of fungi, several
biological phenomena are demonstrable. There is good evidence that the
majority of British boletes are mycorrhizal; several species are known
to be associated only with one species of tree or group of closely
related tree-species. Thus _Suillus grevillei_ and _S. aeruginascens_
(Secretan) Singer grow in association with larch trees; _S. luteus_ and
_Boletus badius_ in contrast grow in association with pine trees;
_Leccinum scabrum_ with birch trees; _L. aurantiacum_ (Fries) S. F.
Gray, with poplar trees and _L. quercinum_ (Pilát) Green & Watling, with
oak trees.
_Boletus edulis_ can be separated into several distinct subspecies which
are associated with different trees; the two commonest subspecies are
those associated with birch and with beech trees. It is well known that
although present in this country during the warmer periods of the
Ice-Age, larch neither survived the intense cold of the last advance of
the ice nor migrated back into Britain after the ice had melted. Thus
all larches which we see in Britain have been planted by man. There is
little doubt that mycelia of many fungi were introduced along with these
plants very probably including the mycelium of the larch-bolete. A
similar pattern can be seen with other introduced trees, although not to
such a marked degree, e.g. spruce trees. The beech tree, however, is
native to the south of England, unlike the larch returning to this
country after the ice had melted; it has been planted extensively
outside its former range in northern areas of the British Isles taking
with it its associated fungi. There is some evidence that some stocks of
beech and fungi have been introduced from continental Europe in
comparatively recent times.
A parallel, yet inexplicable association is found between the bolete
_Suillus bovinus_ (Fries) O. Kuntze and its close relative _Gomphidius
roseus_ (Fries) Karsten where the mycelium of two fungi are found
intertwined forming a close association! Parasitism although rare is
also found amongst the boletes, and an uncommon parasitism at that--a
fungus on a fungus; for example in Britain although infrequent _Boletus
parasiticus_ Fries grows attached and ultimately replaces the
spore-tissue of the common earth-ball (_Scleroderma_, see p. 192).
Those fungi which grow on dead and decaying substrates are called
saprophytes and although the greater number of higher fungi would be
included in this class of organisms the character is infrequent amongst
the boletes. One British example of this type of fungus is the rare
_Boletus sphaerocephalus_ Barla which grows on woody debris.
Chemists have long been interested in boletes, for as noted above the
flesh of some species when exposed to the atmosphere turns vivid
colours, a feature often incorporated into the Latin name, e.g. _Boletus
purpureus_ Persoon, from the purple colours produced whenever the
fruit-body is handled. The reaction appears to be an oxidation where in
the presence of an enzyme and oxygen a pigmented substance or substances
are produced. What the significance of these colour-changes is in nature
is as yet unknown; however, what is interesting is that many of the
chemicals involved are unique and have only recently been analysed
completely; they are related to the quinones.
There is little doubt that it is this rapid and intense blueing of the
flesh of many boletes that has lead to a belief that they are poisonous.
It is uncertain whether there are any truly toxic species of _Boletus_
but several have unpleasant smells and tastes which make them very
unattractive. _Boletus edulis_ is the important ingredient, however,
which gives the distinctive taste to so-called dried mushroom soup.
Thousands of fruit-bodies are collected annually in the forests of
Europe to be later dried and processed for incorporation into soup.
Boletes appear to form an important part of the diet of several rodents
and deer and in Scandinavia in the diet of reindeer.
Probably one of the most obscure of our British boletes is
_Strobilomyces floccopus_ (Fries) Karsten, the ‘Old Man of the Woods’.
It has a black, white and grey woolly, scaly cap and stem, and the flesh
distinctly reddens when exposed to the air. The spores are almost
spherical, purple-black in colour and covered in a coarse network when
seen under the microscope. All these characters readily separate
_Strobilomyces_ from all other European boletes; however, in
Australasia, members of this and related genera form a very important
part of the flora.
~Chroogomphus rutilus~ (Fries) O. K. Miller
Pine spike-cap
_Cap_: width 30-150 mm. _Stem_: width 10-18 mm; length 60-120 mm.
_Description_:
Cap: convex with a pronounced often sharp umbo, wine-coloured, flushed
with bronze-colour at centre and yellow or ochre at margin, viscid but
soon drying and then becoming paler and quite shiny.
Stem: yellowish orange, apricot-coloured or peach-coloured, streaked
with dull wine-colour, spindle-shaped or narrowed gradually to the
apex from a more or less pointed base.
Gills: arcuate-decurrent, distant, at first greyish sepia then dingy
purplish with paler margin, but finally entirely dark purplish brown.
Flesh: lacking distinctive smell and reddish yellow or pale tan in the
cap, rich apricot- or peach-colour towards the stem-base.
Spore-print: purplish black.
Spores: very long, spindle-shaped, smooth, olivaceous purple and
greater than 20 µm in length (20-23 × 6-7 µm).
Marginal cystidia: cylindrical to lance-shaped and up to 100 × 15 µm.
Facial cystidia: similar to marginal cystidia.
_Habitat_ & _Distribution_: Found in pine woods, usually solitary or
in small groups. Fairly common throughout the British Isles and
characteristic of Scots Pine woods.
_General Information_: This fungus can be distinguished by the
purplish or wine-coloured cap and the gills being pigmented from
youth. There is only one other British species of this genus, i.e. _C.
corallinus_ Miller & Watling.
_Chroogomphus_ is separated from _Gomphidius_ by the flesh having an
intense blue-black reaction when placed in solutions containing
iodine, and the gills being coloured from their youth. In many books
_Chroogomphus_ is placed in synonymy with the genus _Gomphidius_.
However, _Gomphidius glutinosus_ (Fries) Fries, _G. roseus_ (Fries)
Karsten and _G. maculatus_ Fries all have whitish gills when immature
which gradually darken, and their flesh simply turns orange-brown in
solutions of iodine. _G. glutinosus_ is uniformly grey in colour and
is most frequently found under spruce and other introduced conifers:
_G. roseus_ has a pale-pinkish coloured cap and white stem, and grows
with pine; _G. maculatus_ grows under larch and is flushed lilaceous
at first but becomes strongly spotted with brown when handled.
_Illustrations_: Hvass 192; LH 213; WD 83^{a}.
[Illustration: Plate 4. Fleshy fungi: Spores blackish and borne on
gills]
~Paxillus involutus~ (Fries) Karsten
Brown roll-rim
_Cap_: width 50-120 mm. _Stem_: width 8-15 mm; height 30-75 mm.
_Description_:
Cap: at first convex with a strongly inrolled, downy margin, but then
expanded and later frequently depressed towards the centre,
clay-coloured, ochre or yellow-rust, slightly velvety but becoming
smooth or sticky particularly in wet weather and readily bruising
red-brown when fresh.
Stem: central or slightly eccentric, thickened upwards,
fibrillose-silky, similarly coloured to the cap but typically streaked
with red-brown particularly with age.
Gills: ochre or yellow-brown then rust and finally darker brown,
decurrent, crowded, often branched and united about the apex of the
stem; easily peeled from the flesh with the fingers and rapidly
becoming red-brown on handling.
Flesh: thick, soft and with slightly astringent smell and yellowish to
brownish but becoming red-brown after exposure to the air.
Spore-print: rust-brown.
Spores: medium-sized, ellipsoid, smooth, deep yellow-brown and rarely
greater than 10 µm in length (8-10 × 5-6 µm).
Marginal cystidia: numerous lance-shaped or spindle-shaped.
Facial cystidia: scattered and similar in shape to marginal cystidia.
_Habitat_ & _Distribution_: Found on heaths and in mixed woods,
particularly where birch has or is now growing, or even accompanying
solitary birch trees.
_General Information_: This fungus is easily recognisable by the
strongly inrolled, woolly margin of the cap and yellow-brown gills
which are easily separable from the cap-flesh. _P. rubicundulus_ P. D.
Orton is similar but grows under alder and has yellow gills unchanging
when handled and dark scales on the cap. _P. atrotomentosus_ (Fries)
Fries and _P. panuoides_ (Fries) Fries both grow on coniferous wood
and have smaller spores; the former is recognised by the dark brown to
almost black shaggy stem and the latter by the shell-shaped cap devoid
almost completely of a stem.
_Illustrations_: F 41c; Hvass 189; LH 185; NB 115⁸; WD 70².
[Illustration: Plate 5. Fleshy fungi: Spores brown and borne on gills]
~Cortinarius pseudosalor~ J. Lange
_Cap_: width 60-125 mm. _Stem_: width 15-25 mm; length up to 180 mm.
_Description_:
Cap: bell-shaped or bluntly conical only slightly expanding with
maturity, smooth or wrinkled at centre but often furrowed at the
margin, slimy, brown with a distinct olive flush when in fresh
condition and becoming ochraceous brown and shiny when dry.
Stem: usually swollen to some degree about the middle, slimy
particularly towards the base, whitish throughout when young except
for a faint amethyst or violaceous flush in the lower part; as the
slime dries the stem becomes shiny and the outer surface breaks up
into fibrillose scales or scaly, irregular ring-zones.
Flesh: lacking distinct smell, white with ochraceous flush in the cap,
white in the stem, thick and soft in the cap but fibrous in the stem.
Gills: adnate, broad, rather thick, frequently veined and distant,
ochraceous brown and finally deep rust-brown.
Spore-print: rust-colour.
Spores: long, slightly almond-shaped in side view, finely warted
throughout and not less than 12 µm in length (13-14 × 7-8 µm).
Marginal cystidia: ellipsoid or club-shaped, hardly different from the
surrounding undeveloped basidia.
Facial cystidia: absent.
_Habitat_ & _Distribution_: Found on the ground in copses and woods
especially those containing beech.
_General Information_: Recognised by the conical, grooved cap and the
slimy spindle-shaped stem with a distinct violaceous flush; this
fungus is often misnamed _C. elatior_ Fries but this is a much less
common fungus. There are several closely related fungi, but these grow
with other tree-species and need much more experience to distinguish
one from the other. _C. pinicola_ P. D. Orton is one such species
growing in the litter under _Pinus sylvestris_, Scots Pine; this
species is fairly common in the remnant pine woods of Northern
Scotland. The large size, sticky or glutinous cap and stem indicate
that this fungus belongs to _Cortinarius_, subgenus _Myxacium_.
_Illustrations_: Hvass 145; LH 162; NB 119; WD 60¹.
[Illustration: Plate 6. Fleshy fungi: Spores brown and borne on gills]
General notes on Cortinarii
The genus _Cortinarius_ is the largest genus of agarics in the British
Isles, indeed in Europe and North America--perhaps in the world. It
includes some of our most beautiful agarics, yet it is one of the least
satisfying to the mycologist because of the difficulties experienced in
identifying collections--partly because many species are so seldom seen.
_Cortinarius_ contains just under two hundred and fifty recognisable
British species, although recent research has shown that many more are
yet to be described from this country as new to science. Except for some
very characteristic species the individual members within the genus
_Cortinarius_ are often very difficult to separate one from the other;
however, _Cortinarius_ is one of our least difficult genera to recognise
in the field owing to the presence when mature of rust-coloured gills
and a cobwebby veil which extends from the margin of the cap to the
stem. This structure is termed a cortina (Fig. 14) and in young
specimens covers the gills with delicate filaments. As the cap expands
the cottony or cobwebby filaments are stretched and either disappear
entirely or may collapse to form a ring-like zone of filaments on the
stem. In some species a second completely enveloping veil is also found,
and this veil is viscid in one distinct group of which _C. pseudosalor_
already described is a member. The gills in the genus are variable in
colour when young although constant for a single species; they may be
lilaceous purple, orange, brown, red, yellow-ochraceous or tan, but
ultimately in all members at maturity they become rust-colour. The
spores under the microscope are richly coloured, yellow to red-brown and
are frequently strongly warted; in mass they are rust-brown and this
character coupled with the presence of the cobweb-like veil
characterises the genus.
Within the genus _Cortinarius_ there is a wide range of characters
varying from species with distinctly sticky caps and stems, some with
sticky caps and dry stems to those with both dry caps and stems. A few
species are very large and fleshy whilst others are quite slender and
many of the latter rapidly change colour on drying out and are then said
to be hygrophanous. However, although there is such a large spectrum of
characters in a single genus the species all have in common the cortina
and rust-coloured gills, the latter often appearing as if powdered with
rusty dust.
Utilising the characters mentioned above this very large genus can be
split into the following six sections, called by the mycologist
subgenera:
a. Large to medium sized fleshy agarics with viscid caps and
stems--_Myxacium_
b. Large, fleshy agarics with viscid or tacky caps when fresh but dry
stems--_Phlegmacium_
c. Large to medium sized agarics with dry, scaly or humid caps and dry
stems which if orange tawny are robust--_Cortinarius_
d. Medium, rarely large, agarics with dry, silky to innately
fibrillose caps, slender stems and frequently with at least part of
the fruit-body yellow, orange or reddish--_Dermocybe_
e. Medium to small agarics with silky fibrillose, non-hygrophanous
caps which may become tacky in wet weather and then usually with
robust, clavate-bulbous stems--_Sericeocybe_
f. Small, less frequently medium or large agarics, all with distinctly
hygrophanous caps--_Hydrocybe_.
In several continental books some or all of these divisions are
recognised as distinct genera in their own right. The subgenus
_Telamonia_ which occurs in many texts was formerly thought to differ
from _Hydrocybe_ in the presence of a universal veil; the universal veil
is a second veil which completely envelopes the fruit-body when it is
young and is in addition to the cortina. However, the modern treatment
would seem to suggest that the presence of the universal veil is not of
the utmost importance and so the two subgenera are incorporated into
one. The name _Hydrocybe_ reflects the character of changing colour as
it dries out because of the loss of water. Within each subgenus the
species are distinguished by the colour of the young gills and of the
cap, the veil colour and texture, and microscopic characters of the
spores, particularly their size.
The majority of species of _Cortinarius_ are mycorrhizal and like the
boletes possess very specific relationships with tree species. Thus some
are typical of coniferous woodland and others typical of deciduous
woodland in general, whilst others typify woods of a particular tree,
e.g. beech, oak, birch, pine, larch. Some species are characteristic of
woods on limestone or chalky soils (calcareous) whilst others are
characteristic of woods on sandy, heathy acidic soils. For example,
_Cortinarius armillatus_ (Fries) Fries which is found in damp woods and
possesses one or more cinnabar-red or scarlet zones on the stem and red
fibrils at the stem-base appears to be connected with birch. Several
species are associated with native trees whilst others have undoubtedly
been introduced from abroad. They are very important in the economy of
the woodland ecosystem.
One of the most beautiful and easily distinguished of our British
species is _Cortinarius violaceus_ (Fries) Fries which has uniformly
deep violet-coloured stem and cap and coloured cystidia on the
gill-margin, a character unusual in _Cortinarius_.
No species are known to be truly poisonous and many species are known to
be edible, but many are too small to be of any value. Some of the larger
species are regarded as good to eat, but frequently are too scarce. Thus
the necessity for experience to recognise the different species, coupled
with their often unpleasant tastes make them an unimportant group of
agarics for eating.
~Russula ochroleuca~ (Secretan) Fries
Common yellow russula
_Cap_: width 50-100 mm. _Stem_: width 20-35 mm; length 50-100 mm.
_Description_: Plate 7.
Cap: yellow-ochre or dull yellow becoming paler with age, or flushed
faintly greyish green, convex but soon expanding and becoming flat or
depressed in the centre, smooth, or granular when young and slightly
tacky in wet weather, faintly striate at the margin.
Stem: white at first then flushed slightly greyish, smooth or
wrinkled, firm at first but quickly becoming soft and fragile.
Flesh: brittle, firm at first then soft, white, yellow under
cap-centre.
Gills: white at first then flushed pale cream-colour, brittle, adnexed
to free, rather distant.
Spore-print: faintly cream when freshly prepared.
Spores: medium-sized, hyaline, broadly ellipsoid or subglobose to
almost globose, coarsely ornamented with prominent warts which stain
blue-black when mounted in solutions containing iodine and which are
faintly interconnected by low ridges, about 8 × 7 µm in size (9-10 ×
7-8 µm).
Marginal cystidia: prominent, lance- to spindle-shaped and often
filled with oily material.
Facial cystidia: similar in shape to marginal cystidia and projecting
some distance from the gill-face.
_Habitat_ & _Distribution_: Commonly found in mixed woods from summer
until late autumn.
_General Information_: Easily recognised by the ochre-yellow cap, very
pale cream-coloured spore-print and greying stem. Two other
yellow-capped species of Russula are commonly found. R. claroflava
Grove with yellow spore-print and blackening fruit-body which grows
with birches in boggy places, and R. lutea (Fries) S. F. Gray which is
much smaller, having a cap up to 50 mm and very deep egg-yellow gills
and spore-print; it grows in deciduous woods.
_Illustrations_: F 22a; Hvass 226; LH 119; NB 137¹; WD 49¹.
General notes on the genus _Russula_
A large genus with nearly one hundred distinct species in the British
Isles and several others yet unrecognised or undocumented. This genus is
composed generally of large toadstools often beautifully coloured,
indeed the majority have brightly coloured caps in reds, purples,
yellows or greens depending on the species although a few are
predominantly white bruising reddish brown or grey to some degree.
Such large and distinctive fungi one would think would be the easiest
members of our flora to identify, unfortunately they are not. They form
a group quite isolated in their relations, the only close relatives
being members of the genus _Lactarius_, to be dealt with later (see p.
50). The flesh of members of both _Lactarius_ and _Russula_ contains
groups of rounded cells, a feature unique amongst agarics and explains
why in _Russula_ the fruit-bodies, cap and gills and sometimes the stem
are brittle and easily break if crushed between the fingers. The
fruit-body does not exude a milky liquid when the flesh is broken.
The spore-print varies, depending on the species involved, from white to
deep ochre and individual spores are covered in a coarse ornamentation
which is composed of isolated warts or warts interconnected by raised
lines, or mixtures of both. The ornamentation stains deep blue-black
when the spores are mounted in solutions containing iodine and the
pattern which is produced appears in many cases to be of a specific
character.
The majority of the species, if not all north-temperate species are
mycorrhizal and the familiar host-tree fungus relationship can be
recognised:--
_R. claroflava_ Grove, with birch in boggy places, _R. emetica_
(Fries) S. F. Gray with pine in wet places, _R. betularum_ Hora with
birch in grassy copses and _R. sardonia_ Fries with pines. Brief notes
are here included giving the basic characters of eight common species,
but it must be appreciated the identification of many species within
this genus is difficult.
~R. atropurpurea~ (Krombholz) Britz.
Blackish purple russula
_Cap_: width 50-100 mm. _Stem_: width 14-25 mm; length 60-80 mm.
Cap: deep reddish purple but becoming spotted with either cream-colour
or white blotches.
Stem: white but becoming flushed greyish or stained brownish with age.
Gills: white then very pale yellow.
Flesh: white in cap and stem.
Spore-print: white.
On the ground in mixed woods and copses, particularly those containing
oak.
[Illustration: Plate 7. Fleshy but brittle fungi: Spores whitish and
borne on gills]
~Russula cyanoxantha~ (Secretan) Fries
_Cap_: width 50-150 mm. _Stem_: width 10-30 mm; length 50-100 mm.
Cap: lilac, bluish to purple often with green tints.
Stem: pure white.
Gills: pure white.
Flesh: white.
Spore-print: white.
Common in deciduous woods, especially beech-woods.
~R. emetica~ (Fries) S. F. Gray
Emetic russula
_Cap_: width 50-100 mm. _Stem_: width 8-15 mm; length 25-70 mm.
Cap: bright scarlet fading with age to become spotted pinkish,
slightly viscid when moist.
Stem: spongy, fragile.
Flesh: white.
Gills: pure white.
Spore-print: pure white.
In pine woods usually in boggy areas.
~R. fellea~ (Fries) Fries
Geranium-scented russula
_Cap_: width 40-75 mm. _Stem_: width 10-20 mm; length 30-75 mm.
Cap: tacky when fresh, straw-coloured or pale tawny brown.
Stem: similarly coloured to the cap.
Gills and flesh: pale straw-colour and smelling of House Geraniums
(i.e. Pelargoniums).
Spore-print: cream-coloured.
Common under beech.
~R. foetens~ (Fries) Fries
Foetid russula
_Cap_: width 70-170 mm. _Stem_: width 15-30 mm; length 50-90 mm.
Cap: slimy, dingy yellow to tawny, margin strongly furrowed and
ornamented with raised bumps.
Stem: whitish then flushed or spotted with rust-brown.
Gills: straw-coloured, often spotted brown with age and beaded with
watery droplets when growing under moist conditions.
Flesh: white to cream, brittle and with foetid-oily smell.
Spore-print: pale cream-colour.
Common in deciduous woods.
~R. mairei~ Singer
_Cap_: width 30-75 mm. _Stem_: width 7-15 mm; length 35-70 mm.
Cap: scarlet red but developing creamy areas with age, dry.
Stem and gills: white but with a distinct although faint greenish grey
flush, the former fairly firm.
Flesh: white.
Spore-print: pure white.
Commonly accompanying beech, even individual trees in gardens.
~R. nigricans~ (Mérat) Fries
Blackening russula
_Cap_: width 75-200 mm. _Stem_: width 15-35 mm; length 25-75 mm.
Cap: cream-coloured then flushed sooty brown, finally black as if
scorched by proximity to bonfire.
Stem: white then dark brown.
Gills: pale ochre reddening when bruised, thick and very distant.
Flesh: white slowly dull red on cutting then brown and finally
changing soot-colour after some time.
Spore-print: white.
Common in deciduous woods.
~R. xerampelina~ (Secretan) Fries