Earthstars

Geastrum species

earthstar_05-04-13.jpg

Photo of earthstars, ball mushrooms with starlike rays, on forest floor
Norman D. Davis, Bugwood.org
Not recommended/not edible
Family

Geastraceae

Description

A roundish ball in the center of starlike rays. Grows on the floor of open woods. July–September. Fruiting body star-shaped; composed of a ball (spore sac) surrounded by 4–10 rays, depending on the species. Ball with an opening or hole at the top. Entire mushroom is grayish brown. Spore print brown. Spores magnified are round, warted.

Lookalikes: None in Missouri. You will know when you have found an earthstar, because no other mushroom looks like it.

Size

Ball width: to 1½ inches; ray length: ½–2 inches.

Earthstar in Morgan County

A cluster of small, round fungi on leaf litter with an outer layer peeled back to create a star shape.
Earthstar in Morgan County
Habitat and conservation

Grows singly or in groups of up to several on the floor of open woods. Missouri has a few different species of earthstars in the genus Geastrum, but they are similar enough to treat as just "earthstars."

image of Earthstars distribution map
Distribution in Missouri

Statewide.

Status

Not edible, but some people like to take home a dried earthstar as a long-lasting, curious souvenir of nature.

Life cycle

Earthstars spend most of the year as a network of fungal cells (mycelium) that penetrate the soil, digesting decaying organic material. When ready to reproduce, the mycelium develops the “earthstar” aboveground. The “ball” is actually a spore sac. When immature, the spore sac is solid inside, but as it matures the inside changes into a mass of powdery spores. When raindrops hit the ball, the spores puff out from a pore at the top of the sac.

Human connections

When dry, the arms of the “star” curl up. If you put your dried earthstar in a little water, the rays open up again! Like wildflowers, fungi can be strikingly beautiful—other times, they are breathtakingly strange. Discovering fungi can bring out our innate capacity for awe and wonder.

Ecosystem connections

Earthstars, like many fungi, live on decaying organic materials. These saprobic fungi play an incredibly important role in breaking down the tough materials living things are made of and returning those nutrients to the soil.