Herald of winter: the mushroom of the first frosts

Some mushrooms you set out for, and some you simply do not expect. The herald of winter (Hygrophorus hypothejus) is the second kind. It comes up when the basket hardly seems necessary any more: the boletes are over, the grass has gone flat, and in the mornings there is hoarfrost on the pine needles.

That is exactly why almost nobody writes about it. And yet it is one of the few mushrooms whose season is only getting going when the rest of the forest is already closing down for winter.

Below: what it looks like, where and when to look for it, why it comes up so late, and what else there is in the forest in these last weeks besides it.

What the herald of winter looks like

There are not many features to go on, but the ones there are are very distinctive.

• Cap olive-brown or yellowish-olive, darker in the centre and paler towards the edge, and very slimy. In a young mushroom it is hemispherical with an inrolled edge, later opening out with a broad umbo.
• Gills widely spaced, thick, waxy to the touch, yellow or golden-yellow, running down onto the stem.
• Stem yellowish to golden-yellow, cylindrical, often curved, slimy as well, with no ring.
• Flesh pale yellow, firm in young mushrooms, softening with age.

Waxy gills are the signature trait of the Hygrophorus genus. Run a finger across them: it feels as if you were touching a wax candle rather than a mushroom gill. Together with the yellow gills and the slimy olive cap, that is already enough to recognise the species. There is a full description with photographs on the page for the herald of winter.

Slime on the cap is normal, not a sign that the mushroom has been lying around. In wet weather there is so much of it that the mushroom barely stays in your hand.

Where and when to look for it

The herald of winter lives with pine. It forms mycorrhiza with pine, so look for it in pine and mixed forests, on sandy soils, in patches of moss and in the needle litter under the trees. It mostly grows in groups, so if you have found one, look more carefully at your feet.

In Ukraine it is recorded in Polissia, the northern forest belt, and in the forest-steppe, and in the Carpathians too. It is picked from September to November, and it fruits most heavily after the first night frosts.

That detail matters when you are planning a trip. You go out for the herald of winter not when it is warm, but when the grass is grey with frost in the morning. If you did not find it in early October, that does not mean it is not there. You may simply have come too early.

Why it comes up so late

The honest answer: we cannot name you the exact mechanism, and no serious source gives a temperature at which mushrooms “stop growing”. That number simply does not exist, however readily it gets published.

What is certain is the fact itself: the season of the herald of winter falls at the end of autumn, and the peak comes after the first light frosts. The mushroom does not depend on summer heat, because it feeds through its mycorrhiza with pine, and pine stays green through November as well. On top of that, at this point it has almost no competitors in the litter: everything that was going to come up in summer is already over.

For a forager the practical conclusion is simple. Late species are not living out the season, they are starting it. So plan your last trip to the forest by the weather rather than by the calendar, and a night below zero here is more of an invitation than a signal to close the season.

What else there is in the forest at this time

The herald of winter is rarely the only find. Here is what turns up alongside it in these weeks.

• **Velvet shank, Flammulina velutipes. It grows in clusters on wood and comes back with every thaw, practically until the snow. Two rules: eat only the cap**, and never raw.
• **Honey fungus. The last flushes often stand right through the light frosts. Boil for at least 30 minutes**, throw the water away, and make your first portion a small one: honey fungus sits heavily with a lot of people.
• **Wood blewit. The main prize of late October in the litter. Boil it for 15 minutes** and pour the water away, otherwise the dish will taste of earth. Everything about it in the kitchen is in the article how to clean and cook wood blewits.
• **Yellow knight** (Tricholoma equestre). It turns up in the same sandy pine forests as the herald of winter, and just as late. But this is a mushroom with a serious warning attached, and it gets its own section below.
• **Slippery jack. Warm October weeks still give slippery jacks (Suillus luteus), but there is a question around them that has nothing to do with poison. Ukraine’s State Forest Resources Agency ranks slippery jack among the strongest accumulators of caesium-137, while the Finnish food safety authority puts the same species in the group with low** accumulation. Two state bodies contradict each other, and we are not hiding it. Our advice is to take the Ukrainian agency’s side: it did its measuring in Ukraine’s forests.
• The last boletes. If a mushroom has frozen where it stands and then thawed, leave it. Thawed flesh becomes a medium for bacteria and mould. To be straight with you: this is a mechanism described in the Czech popular-science press rather than the result of a measurement, but it is worth the caution. More on how mushrooms behave in the cold is in the article can you pick mushrooms after a frost.

How not to mix things up, and what not to listen to

The herald of winter itself has no deadly lookalikes: the slimy olive cap, the yellow waxy gills and the season are distinctive enough. But the late forest has its own traps, and they are not in the herald of winter, they are in the company you pick alongside it.

On wood, look at the substrate. Next to the velvet shank grows the funeral bell, Galerina marginata, a deadly poisonous mushroom that is active in exactly this cold season. There is one distinguishing feature here, and it is reliable: conifer wood means stop. Velvet shank is taken from broadleaf trees, mostly poplars and willows. And one more thing: “it does not survive frost” is not a feature. Next to a deadly mushroom, frost tolerance cannot be a feature at all, because no source confirms any such difference.

The yellow knight is not “just a late mushroom”. After heavy, repeated eating there are documented cases of rhabdomyolysis, the breakdown of muscle tissue, with fatal outcomes, and the French food safety authority concluded that a safe dose cannot be established scientifically. Polish researchers dispute this: by their data, thousands of foragers eat the yellow knight every year without harm. Both positions stay here, and there is only one cautious path: rarely and a little at a time, never several days in a row.

And a word of its own about the folk tests, which for some reason get mentioned especially often in the late forest. None of them work:

• the silver spoon that “goes black” in a pot with a poisonous mushroom;
• the onion that “turns blue” in the cooking water;
• “animals and worms eat it, so it must be all right”;
• “a poisonous mushroom is bright, and this one is pale and modest”;
• “it tastes pleasant, so it is edible”;
• “boiling destroys any poison”.

Not one of these signs has anything behind it. Boiling does not destroy deadly toxins, and a mushroom is identified only by the whole set of its features, not by a spoon.

What to do with it in the kitchen

The herald of winter is edible, though not one of the mushrooms people chase. Its main value is precisely its season: the time when there is nothing else to pick.

Before cooking, the slime is wiped off the cap, rinsed off, or the skin is peeled away, and then the mushroom is fried, braised, pickled or put into soup. It does not need a separate pre-boil with the water poured away, the way wood blewits do.

But one rule holds for any dish of forest mushrooms, the herald of winter included: at least 15 minutes at a steady 70–80 °C all the way through the mushroom. That same temperature, 70 °C, destroys the Echinococcus eggs that a mushroom can carry out of the forest. So “no need to pre-boil” means “no need for a separate first water”, not “you can be careless with the pan”. We have gathered the figures for other species in a cheat sheet, how long to boil mushrooms.

And about moderation, which is the same for the noble mushrooms and for the modest ones. In Ukraine the advice is to eat no more than 200–250 g per adult per week: the mushroom is hard to digest and it takes up whatever is in the soil. And Ukraine’s Public Health Centre advises not giving wild mushrooms to children under 12 at all.

Sources

• Hygrophorus hypothejus on Ukrainian Wikipedia, the source for the edibility, the records in Polissia and the forest-steppe, and the September-to-November season.
• Materials of the State Forest Resources Agency of Ukraine on the accumulation of caesium-137 by forest mushrooms.
• Guidance from the Finnish Food Authority on caesium accumulation in different mushroom species.
• Opinion of the French food safety authority (2003) on the yellow knight, and the objections of Polish researchers.
• Recommendations of the German Federal Institute for Risk Assessment (BfR) and the German Mycological Society (DGfM) on the heat treatment of wild mushrooms, and the consumer guidance of the federal state of Hesse on heating mushrooms to 70 °C.
• Recommendations of the Public Health Centre of Ukraine’s Ministry of Health on eating wild mushrooms.