- Email: [email protected]
Russula sublevispora new to Britain
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Russula sublevispora new to Britain 7 3 II<
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member of subsection Griseinae, Russula sublevispora (Romagn.) Kühner & Romagn. shares the subdued, rather subtle cap colours, mild taste, cream gills and pale spores typical of the group. It recalls a rather stocky specimen of the much more common R. grisea or R. parazurea but its large size and thick-set stipe warn it may be something else. The spores under the microscope are however unique as they have the smallest, isolated warts of any member of this section in Europe. Found growing under a lone, well established oak in a large old garden (Fig. 1), it was collected by Ben and Ayako Sturdy who carefully brought it along, wrapped in newspaper, to the South London Botanical Institute in Norwood Road, where fungal identification workshops are held once a week throughout the autumn.
Romagnesi (1985) gives the stipe as voluminous, and Helga Marxmüller (2014) describes it as massive, Sarnari (1998) says very robust, up to 3.8 cm wide measured at the apex. Compare that to the 1–2 cm wide which would be usual for other members of the Griseinae such as R. ionochlora, R. parazurea, R. atroglauca or R. anatina. Staying more or less cylindrical over its entire length with no tapering, this thick, almost oblong stipe is a good field character. Staying white for a long time it developed some brown spotting with age. The gills were cream, crowded, shallow, compared to the thick flesh of the cap and rather fragile. Sarnari reports them as slightly lardaceous when young but this was not observed in this collection as the carpophores were already mature. With some bifurcating of the gills near the stipe they are reported to resemble those of R. heterophylla. Despite the apparent rarity of this species and its unfamiliarity amongst field mycologists, when the spores are examined under the microscope it becomes unmistakable: ellipsoid-ovoid, 6.5–8.5 x 5.5–6.4 µm with minuscule isolated warts only 0.1–0.3 µm high (Fig. 2). It is for the spores after all, that Romagnesi named this enigmatic species, the specific epithet means ‘almost smooth spores’ and in Germany it is colloquially known as ‘the fragile dotty-spored Brittlegill’. The spore print is dark cream, IIc-d on the Romagnesi (1985) scale, Q on the Kibby (2017) scale. This is paler than the ochre spores of either R. ochrospora or R. medullata, other rare members of the subsection Griseinae with which it could possibly be confused. The cuticle has chains of rather short, swollen hyphal cells as well as numerous non-septate pileocystidia which are clavate to fusiform, sometimes mucronate, darkening in sulphovanillin. This appears to be a genuinely rare species across Europe. Sarnari knew it from only one
Description of the collection The cap, easily reaching to 12 cm, had a pale violet cloudy-grey hue, especially pronounced in a thick marginal belt, with a strongly discolouring pale rust-cream to brownish yellow centre. The cap cuticle, although hard to peel, separated by up to a third of the cap radius. Towards the margin it was finely cracked, almost as if it couldn’t cope with the demands of expansion as the mushroom grew, but the margin itself remained without grooves and fairly smooth. Starting out globose then broadly convex the cap was quite depressed in the centre. The consistency of the flesh was firm to hard, and remained white when cut. It was mild to taste even in the gills, though like many members of this section it can apparently be very slightly acrid. Chemical reactions were fairly standard for the subsection and not of much significance: weakly positive pink with FeSO4 and pale blue with guaiac. The weak reaction to iron sulphate should help separate it quickly from R. grisea, one of the few similar species.
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doi:10.1016/j.fldmyc.2018.04.005
//
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search of the internet revealed a couple of records from Sweden, another from Belgium and one from Denmark. Evidence of its rarity is its absence from every single field guide available in English with the notable exception of the new guide by Kibby (2017). Even Romagnesi, who described the species, knew it only from the area around Paris, and one debated collection from Chaumontel in Northern France. If the species is rare then good illustrations seems to be even rarer. Sarnari bemoans the fact that there is no good iconography in circulation, he suspects the one in Cetto (1989) to be R. vesca and the one in Galli (1996) to be R. grisea. It is hoped that the photograph presented here along with the painting (Fig. 3) by the talented Russian natural history illustrator, Maria Sergeeva will help redress this matter. With so few records it’s hard to say a lot about its habitat; it would appear to favour open grassy spaces between large trees and has been recorded from under a small range of deciduous species including Populus, Carpinus and Quercus with a possible preference for humid loamy clay soils.
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collection in Italy and calls it “rarissima” while Marxmüller tells us she has never actually seen it and had to make her painting from a photograph. In Germany there are only two collections listed by the German Mycological society. A
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Although the site of this first British collection has been under constant observation, it has so far refused to fruit again. Is it possible that in Britain it is being passed over as some other member of the Griseinae? Probably not, the experience amongst all of our fellow European mycologists seems to bear out the notion that this is a truly rare species. Does it have a very specific set of environmental requirements such as very warm to hot open ground perhaps, combined with an association with larger, older trees? Is it a poor competitor? or a sparse fruiter? Speculation as to why it should be so rare will have to remain just that for now until more collections are forthcoming.
References Cetto, B. (1989). I funghi dal vero, vol. 6. Editura Arte Grafiche Saturnia, Trento. Galli, R. (1996). Le Russule. Edinatura, Italy. Kibby, G. (2017). Mushrooms & Toadstools of Britain and Europe Vol. 1. Privately published, [email protected]. Marxmüller, H. (2014). Russularum Icones Vols 1 & 2. Privately published. Romagnesi, H. (1985). Les Russules. 2nd Edition. J. Cramer. Sarnari, M. (1998). Monografia Illustrata del Genere Russula in Europa Vol. 1. A.M.B., Italy.
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Russula sublevispora new to Britain 7 3 II<
A
member of subsection Griseinae, Russula sublevispora (Romagn.) Kühner & Romagn. shares the subdued, rather subtle cap colours, mild taste, cream gills and pale spores typical of the group. It recalls a rather stocky specimen of the much more common R. grisea or R. parazurea but its large size and thick-set stipe warn it may be something else. The spores under the microscope are however unique as they have the smallest, isolated warts of any member of this section in Europe. Found growing under a lone, well established oak in a large old garden (Fig. 1), it was collected by Ben and Ayako Sturdy who carefully brought it along, wrapped in newspaper, to the South London Botanical Institute in Norwood Road, where fungal identification workshops are held once a week throughout the autumn.
Romagnesi (1985) gives the stipe as voluminous, and Helga Marxmüller (2014) describes it as massive, Sarnari (1998) says very robust, up to 3.8 cm wide measured at the apex. Compare that to the 1–2 cm wide which would be usual for other members of the Griseinae such as R. ionochlora, R. parazurea, R. atroglauca or R. anatina. Staying more or less cylindrical over its entire length with no tapering, this thick, almost oblong stipe is a good field character. Staying white for a long time it developed some brown spotting with age. The gills were cream, crowded, shallow, compared to the thick flesh of the cap and rather fragile. Sarnari reports them as slightly lardaceous when young but this was not observed in this collection as the carpophores were already mature. With some bifurcating of the gills near the stipe they are reported to resemble those of R. heterophylla. Despite the apparent rarity of this species and its unfamiliarity amongst field mycologists, when the spores are examined under the microscope it becomes unmistakable: ellipsoid-ovoid, 6.5–8.5 x 5.5–6.4 µm with minuscule isolated warts only 0.1–0.3 µm high (Fig. 2). It is for the spores after all, that Romagnesi named this enigmatic species, the specific epithet means ‘almost smooth spores’ and in Germany it is colloquially known as ‘the fragile dotty-spored Brittlegill’. The spore print is dark cream, IIc-d on the Romagnesi (1985) scale, Q on the Kibby (2017) scale. This is paler than the ochre spores of either R. ochrospora or R. medullata, other rare members of the subsection Griseinae with which it could possibly be confused. The cuticle has chains of rather short, swollen hyphal cells as well as numerous non-septate pileocystidia which are clavate to fusiform, sometimes mucronate, darkening in sulphovanillin. This appears to be a genuinely rare species across Europe. Sarnari knew it from only one
Description of the collection The cap, easily reaching to 12 cm, had a pale violet cloudy-grey hue, especially pronounced in a thick marginal belt, with a strongly discolouring pale rust-cream to brownish yellow centre. The cap cuticle, although hard to peel, separated by up to a third of the cap radius. Towards the margin it was finely cracked, almost as if it couldn’t cope with the demands of expansion as the mushroom grew, but the margin itself remained without grooves and fairly smooth. Starting out globose then broadly convex the cap was quite depressed in the centre. The consistency of the flesh was firm to hard, and remained white when cut. It was mild to taste even in the gills, though like many members of this section it can apparently be very slightly acrid. Chemical reactions were fairly standard for the subsection and not of much significance: weakly positive pink with FeSO4 and pale blue with guaiac. The weak reaction to iron sulphate should help separate it quickly from R. grisea, one of the few similar species.
<; 8 IH 8 H 6 9 9 5 H @= -)
doi:10.1016/j.fldmyc.2018.04.005
//
> I A ED
( (' ") II H FH 9 H ? 9 H 8 H 2 9
E7D=00 7 3 II
search of the internet revealed a couple of records from Sweden, another from Belgium and one from Denmark. Evidence of its rarity is its absence from every single field guide available in English with the notable exception of the new guide by Kibby (2017). Even Romagnesi, who described the species, knew it only from the area around Paris, and one debated collection from Chaumontel in Northern France. If the species is rare then good illustrations seems to be even rarer. Sarnari bemoans the fact that there is no good iconography in circulation, he suspects the one in Cetto (1989) to be R. vesca and the one in Galli (1996) to be R. grisea. It is hoped that the photograph presented here along with the painting (Fig. 3) by the talented Russian natural history illustrator, Maria Sergeeva will help redress this matter. With so few records it’s hard to say a lot about its habitat; it would appear to favour open grassy spaces between large trees and has been recorded from under a small range of deciduous species including Populus, Carpinus and Quercus with a possible preference for humid loamy clay soils.
@ H I H & (' ") @ I % 'G
collection in Italy and calls it “rarissima” while Marxmüller tells us she has never actually seen it and had to make her painting from a photograph. In Germany there are only two collections listed by the German Mycological society. A
/0
> I A ED
= ( (' ") G H 7 @ G 2 II E7D=00 H H
Although the site of this first British collection has been under constant observation, it has so far refused to fruit again. Is it possible that in Britain it is being passed over as some other member of the Griseinae? Probably not, the experience amongst all of our fellow European mycologists seems to bear out the notion that this is a truly rare species. Does it have a very specific set of environmental requirements such as very warm to hot open ground perhaps, combined with an association with larger, older trees? Is it a poor competitor? or a sparse fruiter? Speculation as to why it should be so rare will have to remain just that for now until more collections are forthcoming.
References Cetto, B. (1989). I funghi dal vero, vol. 6. Editura Arte Grafiche Saturnia, Trento. Galli, R. (1996). Le Russule. Edinatura, Italy. Kibby, G. (2017). Mushrooms & Toadstools of Britain and Europe Vol. 1. Privately published, [email protected]. Marxmüller, H. (2014). Russularum Icones Vols 1 & 2. Privately published. Romagnesi, H. (1985). Les Russules. 2nd Edition. J. Cramer. Sarnari, M. (1998). Monografia Illustrata del Genere Russula in Europa Vol. 1. A.M.B., Italy.
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