Gooseberry Brittlegill

Russula queletii is a mid-sized, richly coloured brittlegill named for the nineteenth-century French mycologist Lucien Quélet. Its English name comes from the fruity odour of fresh specimens, which many people compare to gooseberries or to fruit compote, and that smell is one of the more useful field characters in a genus where colour alone is famously unreliable.

The species sits in a small cluster of purple, spruce-associated brittlegills that also includes R. sardonia and R. torulosa. All three share dark wine to violet caps and a coloured flush on the stipe, and separating them depends on gill colour, host tree and soil type rather than on cap colour, which varies enormously with weather and light exposure.

As a Russula it shows the family's diagnostic anatomy: brittle, granular flesh that snaps rather than tears, gills that shatter under a fingernail, no ring, no volva, and no latex. It is a member of the Russulaceae and an obligate ectomycorrhizal partner of conifers.

Cap

The cap is 3–8 cm across, convex then flattening and finally slightly depressed. Colour is a deep wine-purple to violet-crimson, usually darkest around the centre where it can look almost blackish-purple, and often fading to a paler lilac or olive-tinged tone toward the margin in exposed specimens. The surface is matt to slightly greasy, and the cuticle peels about halfway to the centre. The margin is even at first, becoming faintly furrowed with age.

Gills

Gills are adnexed, moderately spaced, brittle, and pale cream throughout, never a strong yellow. They may show a faint violet tint where they meet the cap edge in very fresh specimens.

Stipe

The stipe is 4–8 cm tall and 1–2 cm thick, cylindrical, and washed with a clear purple to wine flush over a whitish ground, usually strongest in the lower half. It is stuffed and becomes softly hollow, faintly ridged lengthwise, with no ring and no swollen or sheathed base.

Flesh & spore print

Flesh is white, sometimes tinged purple directly under the cuticle, and does not change colour appreciably when cut. Fresh material has a distinct fruity smell recalling gooseberries. The spore print is pale cream, and spores are warty with fine connecting ridges.

This is a brittlegill of spruce, growing in both natural spruce forest and older spruce plantations, and occasionally reported under pine and silver fir. It has a marked preference for calcareous or at least base-rich soils, so it is often found on chalk downland plantations, limestone hills and clay soils rather than on acid sand or peat.

It is widespread in temperate and montane Europe, common in central and northern parts of the range wherever spruce is established, with comparable records from parts of North America. Fruiting is typical of the autumn flush, running from late summer into mid-autumn, often scattered singly or in small troops among needle litter and mosses.

Russula queletii forms ectomycorrhizas with spruce and related conifers. The fungus wraps fine feeder roots in a dense hyphal mantle and extends a network of absorptive hyphae far out into needle litter and mineral soil, capturing phosphorus, nitrogen and trace elements that it exchanges for photosynthetic sugars from the tree.

Because it depends on a living host, it fruits only in stands with established trees, and its presence on chalk plantations tracks the maturity of those plantations. The fleshy fruiting bodies decay quickly and are heavily used by fungus gnats and slugs, which help move spores through the litter layer.

Russula sardonia is the closest match: it too has a dark purple cap and a purple-flushed stipe, but its gills are a clear pale yellow rather than cream, and it grows with pine on acid, often sandy ground rather than with spruce on lime. Russula torulosa is stockier with a firmer, more compact stipe and grows with pine on calcareous soils in warmer regions.

Russula fragilis also has purple tones and cream gills, but it is much smaller and more fragile, with a finely toothed or notched gill edge visible under a hand lens and a white, unflushed stipe. Russula atropurpurea has a blackish-purple, often blotchy cap but a plain white stipe and grows chiefly with oak and beech.