What Is the Blusher Mushroom? Blushing Flesh and Cooking

Blushers are medium to large gilled mushrooms with dull pinkish brown caps, small grayish warts scattered over the surface, and white gills that flush pink wherever something has eaten them. The blusher is one of the few members of the Amanita family with a long European tradition of eating, set against a much longer list of relatives that are dangerous or lethal.

The name comes from the blush. Cut flesh, bruised gills and old larval tunnels all turn pink and then a dull wine red, usually within a few minutes. That reaction earned the mushroom a friendly common name in half a dozen languages, and it also leads people to trust it faster than they should.

European foragers who pick it usually describe it the same way, as the one mushroom in this genus they carry home, with nothing else from the same wood. That rule concerns the picker more than the mushroom. It exists because a mistake here costs far more than an upset stomach, and because the characters that separate a blusher from its worst relatives are small, structural and easy to destroy while collecting.

Work from the base upward, and lift the whole mushroom out of the ground before you decide anything. Every Amanita question comes down to the base, and if you snap a specimen off at soil level, you have already thrown away the evidence.

Four characters carry the identification, and no single one of them is enough on its own. The stain in the first row of the table places a mushroom in a group without clearing it as safe, and the other three rows do the naming.

The cap warts are soft and grayish pink, and they rub away easily, so heavy rain can strip a cap bare. They are remains of the veil that wrapped the whole young mushroom, and they sit on top of the cap surface without forming part of it. Washed caps still belong to the same species, but each one leaves you one fewer character, and the remaining ones must carry more weight. How often that happens depends on the weather the mushroom grew through, so the same species can look very different across one wet autumn.

The ring repays a slow look. Hold the stem upright and read the surface facing the cap, where fine grooves run radially across it, easy to miss once the ring has collapsed against the stem. Young buttons hide most of this, because everything that answers the question is still sealed inside the veil. Leave the smallest ones alone instead of naming them on hope.

The blush draws more questions than any other character, and it needs the most care. It usually shows within a few minutes of a cut, but it comes on slowly in cold weather and can be faint on a very young button.

The stain moves a mushroom into a group and never out of the genus.

What a positive test is worth

So a specimen that has not reddened yet stays in contention, and one that has reddened still needs naming. The stain places a mushroom in a group and leaves the naming to the base and the ring. Treat a quick red flush as the start of the check.

Under a microscope the spores are amyloid, meaning they stain blue-black in iodine, and that cleanly separates this group from several relatives whose spores do not. The test ends arguments, yet nobody standing in a wood can run it. It belongs in your record, while the field decision rests on what you can see.

What you do have in a wood is time. Lay a specimen on a tray for ten minutes with its base cleaned and its stem cut, and it will show you the stain, the ring surface and the shape of the bulb. None of that survives a ride loose in a bag.

Cook a blusher through, and treat this as more than the usual advice about wild mushrooms digesting better when cooked. Raw blusher flesh contains rubescenslysin, a protein of roughly 35 kilodaltons that breaks open red blood cells, and a laboratory study of rubescenslysin found white blood cells more sensitive to it than red ones. The protein is thermolabile, so heat unfolds it, and an unfolded protein of this kind does not reassemble on cooling.

The laboratory work behind that toxin is dramatic and needs careful reading. In an animal study of rubescenslysin, rats given the purified protein by injection died at 1.4 milligrams per kilogram, with haemolysis and lung damage. Injecting isolated protein into a rat is a long way from eating a plate of undercooked mushroom, and heat-sensitive toxins of this class rarely cause real poisonings because cooking removes them. People who eat undercooked blushers report stomach upset, cramping and vomiting, with nothing resembling the animal studies.

When this goes wrong, the pan is almost always to blame. Loaded with wet mushrooms, a pan drops below frying temperature and steams them in their own liquid, which browns nothing and leaves thick pieces barely warmed through. Cooking in two batches fixes it, and so does letting the released water boil off before you turn the heat down.

In the pan the species tastes mild and slightly nutty, firm when young, and soft and watery once the cap has flattened. Most people who pick it take only young, tight caps, both for the texture and because a young specimen still has all its identifying characters attached. Drying does not replace cooking here. Dried slices have lost their water without necessarily reaching any temperature, so dried blusher still goes into a hot pan or a long simmer before it reaches a cold dish.

The blusher is mycorrhizal, trading sugars and minerals with living tree roots, and it cannot live apart from its partner. It is unusually flexible about which partner it takes, working with beech, oak and birch as readily as with pine and spruce. That flexibility puts it in almost every kind of European woodland.

Poor acidic ground suits it better than rich soil, so heathy birch woods and old conifer plantations often produce more blushers than a fertile beech hanger. The preference follows from the partnership itself. Trees on thin acidic soil gain more from trading sugar for minerals they cannot reach, so the fungi offering that trade earn more there.

The season runs long by Amanita standards. Blushers start in early summer, well before most autumn species, and keep going until the first hard frosts. First Nature's account of the blusher gives June to October as the main run in Britain and Ireland. That early start is easy to overlook, since a June flush arrives when most people are not looking and the woods hold little else of any size.

Weather sets the timing and also changes what the mushroom looks like when you find it. Dry spells leave the warts intact and long wet ones wash them away, so a basket picked after four days of rain can look like a different species to someone working from photographs.

The blusher's introduced range tells the same story as the pine plantation species. It reached Chile, Argentina, Australia and South Africa on the roots of planted European trees, and it lives there inside those plantations without spreading into native forest.

Larvae find the blusher early and thoroughly, and with this species that carries extra weight. Old tunnels through the stem turn red, so a heavily infested specimen often shows the clearest color change and makes the poorest eating.

American readers should stop at the name and check it. Mycologists described Amanita rubescens from northern Europe, and the specialist treatment of the genus in Studies in the Amanitaceae states that no rubescent North or Central American material is assignable to it.

Two replacement names already circulate, and you should recognize both on a label. In western North America the reddening species is Amanita novinupta, the blushing bride, which has a formal description of its own. East of the Rockies the situation is looser. MushroomExpert's account of Amanita rubescens places several probably unnamed reddening species there under the provisional working name Amanita amerirubescens while mycologists sort the group out.

Provisional names mark a question still open. This one says that someone has shown these are not the European mushroom, without yet showing how many species they are. The gap has practical weight, because nobody gathered the European edibility reports from those populations. So if you live in America, you are working with a mushroom whose identity nobody has pinned down and whose eating record came from another continent, a thinner basis than the name's popularity suggests.

The species sits in a group whose members have amyloid spores and bulbous but uncupped bases, and that structure, more than color, explains how the genus splits. Color is the character people reach for first in this genus and the one that survives least. Rain can bleach a cap, frost can brown a specimen, and a young one can still sit half in its veil, yet all three may be the same species. The base and the ring will say so when the color does not.