Identification of the Larger Fungi. Roy Watling
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.
Plate 7. Fleshy but brittle fungi: Spores whitish and borne on gills
Larger illustration
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