Wolf's-Milk Slime (Toothpaste Slime)

Lycogala epidendrum

wolfs-milk_pink.jpg

Photo of wolf's-milk slime, a small pinkish rounded slime mold
Wolf's-milk slime (toothpaste slime)
Lisa K. Suits
Not recommended/not edible
Family

Reticulariaceae (a family of amoebozoans, which are not fungi)

Description

Little, round, reddish pink balls; exude a pinkish orange paste when popped. Grows in groups on dead wood, especially large logs. June–November. Fruiting body round; outside bright pinkish orange when young, becoming tannish olive with age; inside bright pinkish orange to pinkish gray, becoming ocher with age; outside texture smooth; inside texture pastelike, becoming powdery with age. Spore print pinkish gray to ocher. Spores magnified are round, netted. This slime mold resembles a tiny reddish pink puffball. Before it is fully mature, you can pop it and a pinkish orange substance, with the texture of toothpaste, will ooze out.

Lookalikes: None in Missouri.

Size

Fruiting body width and height: 1⁄3–5⁄8 inch.

wolfs-milk_slime.jpg

Photo of wolf's-milk slime, young, orange, funguslike balls
Wolf's-Milk Slime
Wolf's-milk slime grows on rotting wood

wolfs-milk_slime_old.jpg

Photo of wolf's-milk slime, old, grayish balls past maturity
Wolf's-Milk Slime (Older Specimens)
Wolf's-milk slime (older specimens)
Habitat and conservation

Grows in groups on dead wood, especially large logs. Thought it may seem like one, this species isn't actually a mushroom or fungus. It belongs to a group called slime molds, or myxomycetes—a group of funguslike organisms that at one time were regarded as animals, then thought to be plants, then fungi. Now, because of DNA studies, slime molds are believed to be closer to the protozoa. They are studied by botanists and mycologists.

image of Wolf's-Milk Slime Toothpaste Slime distribution map
Distribution in Missouri

Statewide.

Status

Not edible.

Life cycle

Slime molds are in a different kingdom from fungi and are more closely related to single-celled organisms. They have two life-cycle stages. The first, “plasmodium” stage is rarely noticed. It is like a huge, single-celled amoeba that creeps on dead plant material in long thin strands, engulfing and digesting bacteria, yeasts, and fungi. When ready to reproduce, it enters its funguslike “sporangia” stage, which makes spores that float away to become new plasmodia elsewhere.

Human connections

Slime molds are weirdly beautiful and have even inspired science fiction movies (such as "The Blob" in 1958). They are studied for their unusual cellular characteristics. We include this species here because mushroom hunters and hikers see it a lot and many assume it's a fungus.

Ecosystem connections

This species feeds on bacteria, yeasts, and fungi that colonize decaying materials such as rotting wood. It is in turn consumed by other organisms, such as fungi, nematodes, and perhaps small insects—all at a tiny scale, at the base of the ecosystem.