Velvet Brittlegill Identification Guide

First Impression and Setting

Velvet Brittlegill is a fungus of warm, well-drained broadleaf woodland. The typical scene is a beech or oak wood on loam or chalk, sometimes with hornbeam, occasionally at the margin of a fir or spruce stand, with a fairly open litter layer. It fruits early for its genus, often from July, and continues into October, appearing singly or in small scattered groups pushing up through leaf litter.

What you notice first is a firm, medium-large, brightly coloured mushroom whose cap looks oddly matt, as though it has been dusted with fine powder, and which sits on a white stem carrying a distinct lilac or violet blush toward the base. That pairing, a velvety cap and a lilac-flushed stipe, is close to diagnostic and worth checking on every yellow or purplish brittlegill you meet.

Confirming It Is a Brittlegill at All

Before the species, establish the genus. Bend a gill sideways with a fingernail: in this group the gill snaps cleanly and crumbles rather than flexing. Snap the stipe across: it fractures like a stick of chalk, with a granular break, not a fibrous tear. Both behaviours come from the nests of rounded cells in the flesh, and they immediately separate brittlegills from milkcaps, which exude latex, and from the fibrous-stemmed genera.

Check also for the absence of any veil: no ring, no volva, no cortina, no fragments on the cap margin.

Reading the Cap

The cap is 5 to 10 cm across, occasionally 12, convex when young, then flat and finally slightly depressed at the centre, with a margin that stays even and only becomes faintly grooved in old material.

Colour is genuinely variable, which is the main obstacle for beginners. There is a lemon or ochre-yellow form, sometimes named as forma citrina, and there are forms flushed with wine-purple, violet, rose-pink or olive over a yellow ground, frequently as an uneven mosaic where the centre is purplish and the margin yellow, or the reverse. Do not try to identify the species on colour alone.

The surface texture is more reliable. When young and dry, it is finely pruinose to velvety, matt like fine suede, with no shine at all. In wet weather, and in age, the bloom wears off and the cap becomes smoother and can look slightly greasy, so examine young caps and the outer zone where the bloom survives longest.

Test the cuticle by pulling at the margin with a fingernail: it peels only about a quarter to a third of the way in, typical of the firm-fleshed section this species belongs to.

Gills, Stipe and Flesh

The gills are pale cream, moderately crowded, adnexed to almost free at the stipe, fairly narrow, with a few forkings near the stem and even edges. They slowly spot ochre or rusty-brown where bruised or with age. Their pale cream tone is worth noting as a first estimate of spore colour.

The stipe is 4 to 9 cm long and 1.5 to 3 cm thick, cylindrical or slightly clubbed, firm and solid at first, becoming spongy and chambered inside with age. It is white overall but flushed lilac to violet, usually best developed in the lower half and at the very base, and typically as a diffuse wash rather than sharp banding. Handling and age turn the white parts ochre-brown. On some collections the flush is faint, so look at the base in good light and scrape away adhering soil.

The flesh is white, firm and chalky, unchanging or slowly discolouring brownish where damaged. The odour is mild in young fruit bodies but develops with age into a distinctly briny, seashore or low-tide note, an odour shared with a well-known related group and a useful supporting character on mature material.

If you carry reagents, a drop of iron sulphate solution on the stipe flesh tends toward a greyish-green rather than the pink or salmon reaction typical of most brittlegills, which reflects this species' relationships within the genus.

Taking and Reading a Spore Print

Spore colour is the backbone of brittlegill identification, so take the print properly. Choose a fully mature cap, cut the stipe off flush, and set the cap gills-down on white card, covered with a bowl to hold humidity, for six to twelve hours or overnight.

Then read it in daylight, not artificial light, and read it thick. Scrape the deposit into a dense heap with a knife blade and press it flat under a glass slide; a thin scatter always looks paler than the true colour. For this species the print is pale cream, at the whitish end of the cream range, and clearly not the deep ochre of the darker-spored groups.

Microscopically, the spores are subglobose, about 7 to 9 by 6 to 7.5 micrometres, ornamented with warts up to about 1 micrometre high that are partly joined by fine connecting lines into an incomplete network. The ornament is amyloid, staining blue-black in Melzer's reagent, which is standard for the genus.

Substrate, Season and Ecology

This species is ectomycorrhizal. Its mycelium forms sheaths around the fine root tips of beech, oak and hornbeam, and sometimes of silver fir and spruce, exchanging water and mineral nutrients for carbon from the tree. It has a preference for neutral to calcareous, well-drained, warm soils and is more frequent in southern and lowland regions, thinning out northward.

Fruiting begins in early summer, earlier than much of the genus, and runs to mid autumn, following rain in warm weather. Because the partnership is with long-lived trees, the same patches produce fruit bodies year after year.

Sorting the Look-alikes

Russula amoena is the closest relative and the hardest separation. It also has a velvety-pruinose cap and a coloured stipe, but it is smaller, its cap is more uniformly violet to carmine with olive tints and lacks the strong yellow component, and its stipe is more evenly and strongly flushed pinkish-violet along its whole length. Habitat leans toward oak and hornbeam.

Russula ochroleuca is a common plain ochre-yellow species, but its cap is smooth and slightly shiny rather than velvety, its stipe is pure white greying with age, with no lilac at all, and it favours acid soils.

Russula claroflava is bright chrome-yellow with a white stipe, grows in wet birch woods, and its flesh greys and then blackens where cut, a reaction absent here.

Russula fellea is uniformly straw to honey-coloured across cap, gills and stipe, with a smooth cap and no violet tones.

The Russula xerampelina group shares the briny odour, but its cap is smooth rather than pruinose, its stipe is usually flushed reddish and browns strongly on handling, and its spore print is a deeper cream to ochre.

Russula cyanoxantha has a greasy-looking cap and gills that flex like soft plastic without snapping, plus a white print.

Russula turci has a violet cap and a pale stipe but gives a strong iodine-like smell at the stipe base, which this species does not.