Cortinarius roblerauli

Cortinarius roblerauli belongs to the Phlegmacium group - the viscid or slimy-capped webcaps - characterised by a notably glutinous cap surface when wet, a distinctly bulbous or club-shaped stem base, and the universal Cortinarius features of a cobwebby cortina and rust-brown spore print.

Cap

In fresh, moist conditions the cap surface feels decidedly sticky or slimy to the touch, a character immediately distinguishable from dry-capped webcaps.

Colour is ochre-brown to tawny-orange or chestnut-brown, sometimes with a greenish-olivaceous centre in the freshest specimens, drying to a dull pale buff.

Gills

The gills begin pale and may show a faint lilac-grey tint in the youngest specimens - a faint trace of the violet pigments common in the genus - before maturing through clay-buff to deep rusty cinnamon-brown as the spore crop ripens.

Stem

The stem base is notably swollen to marginately bulbous, which combined with the viscid cap and rusty spore print places this species firmly in the Phlegmacium webcap complex.

The cortina is most visible in young mushrooms as silky whitish threads between the cap margin and upper stem. When it collapses it leaves a ring of rust-brown spore deposits on the stem - the lingering evidence of the veil.

Flesh

Flesh does not change colour when cut.

Potentially fatal through progressive kidney failure. Cortinarius roblerauli must not be eaten.

As a Phlegmacium-group webcap in Nothofagus forest, it is presumed to carry orellanine-class nephrotoxin risk consistent with the global Cortinarius pattern. South American mycotoxicological literature confirms that webcap ingestion in Patagonian forests has caused severe nephrotoxic injury in humans.

There is no antidote to orellanine; treatment is limited to supportive care, haemodialysis, and in severe cases kidney transplantation.

Four features place this in the highest practical risk category:

• a long latency
• no antidote
• a heat-stable toxin
• potentially irreversible renal damage

If any Cortinarius from this region is suspected to have been ingested - even a single taste, even weeks previously - contact poison emergency services without waiting for symptoms. In Chile, contact CITUC (Centro de Información Toxicológica UC, +56 2 2635 3800). Do not wait for kidney symptoms to appear before seeking help.

Cortinarius roblerauli is classified in the Phlegmacium group of the genus Cortinarius, a clade documented globally to contain orellanine-class nephrotoxins in numerous species.

Orellanine (3,3′,4,4′-tetrahydroxydipyridine N,N′-dioxide) is a polypyridine N-oxide. It is absorbed from the gastrointestinal tract, circulates to the kidneys, and there undergoes metabolic conversion to compounds that selectively destroy renal proximal tubule cells by generating reactive oxygen species and inhibiting cellular protein synthesis. The result is progressive and potentially irreversible tubular necrosis.

Orellanine is chemically stable - it resists boiling, frying, drying, freezing, and pickling without losing nephrotoxic activity.

It was first isolated from the European Cortinarius orellanus. Related species across the global Cortinarius phylogeny, including Nothofagus-associated South American webcaps, are known or strongly suspected to carry structurally analogous nephrotoxins.

Specific analytical confirmation of orellanine in C. roblerauli is limited in the published literature at the time of writing. But precautionary classification as carrying full orellanin-class risk is the standard position adopted by Chilean mycological and toxicological authorities for all Phlegmacium-group webcaps in Nothofagus forests.

Orellanine poisoning is defined by an insidiously long latency between ingestion and the onset of clinical symptoms - typically two to four weeks, with a documented range extending from a few days to over a month.

This extended silent phase is the most medically dangerous feature of webcap poisoning: the victim may feel entirely well for weeks, with no gastrointestinal warning, while progressive and irreversible renal tubular damage accumulates.

When symptoms eventually appear, they include:

• intense thirst
• nausea and vomiting
• severe fatigue
• headache
• anorexia
• lower back or flank pain, indicating renal involvement
• disruption of urinary output (initially excessive urination, potentially shifting to markedly reduced output as renal failure progresses)

These progress to the clinical and laboratory picture of acute tubular necrosis and acute interstitial nephritis: rising serum creatinine and urea, metabolic acidosis, and oliguria or anuria.

In severe or untreated cases the outcome is end-stage renal failure requiring long-term haemodialysis or kidney transplantation.

The extreme latency also severely complicates the medical diagnosis: a patient presenting with renal failure weeks after eating a Patagonian forest mushroom may not spontaneously make the connection, and physicians not alert to orellanine toxidrome may not enquire.

DO NOT EAT. Cortinarius roblerauli is a toxic mushroom of the Phlegmacium webcap group, presumed to carry orellanine-class nephrotoxins consistent with the global Cortinarius risk profile.

No safe preparation method exists: orellanine is fully heat-stable and survives boiling, frying, drying, and any other domestic food preparation. There is no established culinary tradition for this species in Chile or Argentina.

The latency of up to four weeks before kidney failure symptoms appear means that a forager can eat this mushroom, feel entirely well for weeks, and sustain irreversible renal damage before any link to the mushroom is apparent.

If there is any suspicion that this or any other webcap has been consumed, contact CITUC (Chile, +56 2 2635 3800) or CENATOXA (Argentina, +54 11 4963-5063) immediately.

Never collect, taste, or experiment with any viscid-capped, rusty-spored, cobwebby-veiled mushroom in Nothofagus forest, regardless of apparent abundance or apparent safety.

This species is inseparably linked to Nothofagus obliqua (roble, or Chilean deciduous beech), the principal Nothofagus species of central and south-central Chile's Andean foothills. The name roblerauli pays direct tribute to this ecological bond.

The Nothofagus obliqua woodland - the robleral - is a distinctly Chilean forest type, found in the transition zone between the Mediterranean-influenced central Chilean forests and the wetter temperate rainforest further south.

Cortinarius roblerauli fruits on the ground within this woodland type, forming an obligate ectomycorrhizal partnership with the tree roots. The fungal mycelium threads through the soil in intimate contact with feeder roots, exchanging mineral nutrients and water for photosynthetic sugars - a relationship that may persist for decades in an undisturbed forest.

The mushroom is strictly limited to living Nothofagus forest with moist, organic, acidic soil; it will not appear in cleared land, exotic plantations, or degraded secondary growth. Typical microhabitat is among deep beech leaf litter on flat valley floors or gentle slopes facing prevailing wet weather.

Fruiting occurs in the Southern Hemisphere late summer and autumn, from approximately February to June.

The physiological trigger is the combination of cooling soil temperatures as the Chilean summer fades - dropping from the warm summer range above 16 °C down through 10-14 °C - with the arrival of sustained autumn rainfall from westerly frontal systems.

A flush lag of 10-21 days typically follows a triggering rain event, reflecting the slow, mycorrhizal-dependent growth process in which fruiting bodies push up from established mycelium rather than generating de novo from spores.

The peak is mid-March to late April in most sites. At higher Andean elevations the season is compressed into April-May before snowfall ends fruiting, while at lower coastal-Andean sites it may begin in February and persist into June in mild, sheltered ravines.

As an obligate ectomycorrhizal fungus, Cortinarius roblerauli cannot fruit without a living Nothofagus host tree, and depends on the accumulated subterranean mycelial network for all its energy and nutrients.

The visible fruiting body is only the reproductive organ - the mushroom itself - while the true organism is the vast underground web of hyphae ramifying through the forest soil.

Fruiting bodies emerge singly or in small scattered groups of two to five, typically aligned loosely with the underground root paths of host trees. Dense clusters are not characteristic of this species.

Because the mycelial network is perennial, the same sites may produce mushrooms in successive years when autumn conditions are suitable. Drought or unusually early snowfall can suppress fruiting in a given year without eliminating the population.

Southern Hemisphere late summer to autumn species in Nothofagus obliqua forest. Fruiting is triggered by the combination of declining soil temperature (falling below ~15 °C after summer) and sustained autumn rainfall from westerly frontal systems (20+ mm over 14 days). Typical flush lag 10-21 days reflecting the slow mycorrhizal fruiting body development typical of Phlegmacium-group Cortinarius. Peak mid-March to late April; season may extend into June at lower-elevation, wetter, coastal-Andean sites.

In central-southern Chile's Nothofagus obliqua forests, Cortinarius roblerauli can be confused with multiple species.

Within the genus Cortinarius, numerous other Phlegmacium and non-Phlegmacium species co-occur in the same forests and are indistinguishable to non-specialists in the field. All share the rust-brown spore print, cobwebby partial veil, and ectomycorrhizal Nothofagus habitat, and all must be treated with equivalent caution.

Outside the genus, the most realistic field confusions are:

• edible boletes, which have pores rather than gills - an absolute distinction
• Rozites caperatus (the gypsy mushroom), with a wrinkled-silvery cap and a persistent membranous ring rather than a cobwebby cortina, and currently placed in Cortinarius by many authorities - also avoid
• viscid-capped Hebeloma species, which share moist habitats and brownish caps but have a mealy odour, a pinkish-brown (not rusty cinnamon) spore print, and no obvious cortina remnant zone on the stem

Any viscid-capped, gilled mushroom with a rust-brown spore print and cobwebby veil remnants found in Nothofagus obliqua forest is essentially certainly a Cortinarius and must not be eaten.