Welcome parasite

When is a mushroom not a mushroom? Well, maybe when it's two or more different species combined. Like the lichens, a fungus and an algae and maybe a bacteria forming one composite organism. Or when it's a fungus that has cannibalized a "normal" mushroom, like the so-called lobster mushroom, neither lobster nor mushroom.

Hypomyces lactifluorum.

All mushrooms are fungi, but most fungi are not mushrooms. Most of the typical mushrooms, fruiting bodies with a stem and a cap, are Basidiomycetes. Lobster "mushrooms" belong to a separate phylum of the fungi, the Ascomycetes, or sac fungi. 

This is the largest phylum of Fungi, with over 64,000 species. ... Familiar examples of sac fungi include morels, truffles, brewers' and bakers' yeast, dead man's fingers, and cup fungi. The fungal symbionts in the majority of lichens ... belong to the Ascomycota. (Wikipedia)

One of these Ascomycetes, Hypomyces lactifluorum, is a parasite that overwhelms mushrooms such as the white Russula brevipes, so common in our local forests. It engulfs the entire mushroom, cap, gills, and stalk, with bright orange flesh, changing the form of the mushroom, contorting it into fantastic shapes.

Same lobster "mushroom", from a different angle.

I saw several of these last week; none were entire; whether they've been eaten by slugs or raccoons or even bears, or whether the underlying mushroom has disintegrated as the orange coating grew, I can't tell.

Russula brevipes, the prey species. They crumble easily, are often slug-eaten.

The invading fungus changes the taste and edibility of the host mushroom; R. brevipes is basically tasteless; once parasitized, it's edible and choice.

Even the DNA changes!

A 2018 study (Laperriere et al.) determined that Hypomyces lactifluorum gradually conquers the host mushroom; during development of the Hypomyces, the host's DNA decreases; ... when the "lobster mushroom" is contorted and orange, very little of the host mushroom's DNA is still present, even though the interior flesh appears identical and unchanged. (MushroomExpert)

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El reino de los hongos es enorme y variado. Entre ellos, existen los de las divisiones Basidiomycota, que incluye la mayoría de las setas familiares y Ascomycota, que incluye una gran diversidad de tipos de hongo como por ejemplo las levaduras, los componentes de la mayoría de los líquenes, los mohos de pan, las trufas, etc.

Los hongos "langosta" son uno de estos Ascomicetos, Hypomyces lactifluorum. Este hongo es un parásito que invade hongos como el Russula brevipes, tan común en nuestros bosques. Envuelve el hongo entero, desde el sombrero, las laminillas, y el tallo, con una carne anaranjado vívido, aumentando y retorciendo el hongo original.

1. Hypomyces lactifluorum.
2. El mismo, visto desde otro ángulo.
3. Russula brevipes, el hongo que forma la base del hongo langosta.

Vi varios de estos la semana pasada; ninguno entero; si es que los han estado comiendo las babosas o los mapaches o hasta los oso, o es que el hongo original se ha desmoronado, no lo sé.

El hongo invasor cambia el sabor y la comestiblidad del hongo original. R. brevipes no sabe a nada (dice el libro guía, "no vale la pena comerlo"); y con el parásito, es delicioso y sano.

¡Y hasta cambia su ADN!

Un estudio en 2018 (Laperriere et al.) comprobó que Hypomyces lactifluorum cambia el hongo receptor poco a poco; durante el desarrollo del Hypomyces, el ADN del huésped  disminuye; ... cuando el "hongo langosta" está retorcido y anaranjado, muy poco del ADN del hongo huésped sigue presente, aunque la carne interior parece ser idéntico, sin haber cambiado. (MushroomExpert)