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Myxomycetes: The Slime Molds

[ Protista > Myxomycota . . . ]

by Michael Kuo


They're not mushrooms--in fact, they're not even fungi--but they do wind up on a mushroomer's radar screen with some frequency, usually as "sporangia" (see below). Is it a puffball? Is it a sickening mass of jellylike globules? Why am I taking a picture of this?

. . . and so on. Obviously, if you want good information about slime molds, you'll need to go elsewhere on the Internet. I just checked for "SlimeMoldExpert.Com" and got nothing--but see the links at the bottom of this page. If you are a slime mold expert, please try not to laugh as I stumble through a brief description of the slime mold life cycle.


This stage is the creepy stage. Like something out of a B-movie, the slime mold plasmodium is a mass of glistening veinlike material that creeps across dead leaves or wood at the rate of as much as an inch per hour, growing, eating, and probably doing other nasty things we don't even want to know about. There are no cell walls in the plasmodium, and its motion is the result of protoplasm flowing rhythmically through the organism.


When the plasmodium runs out of food (or when light or moisture changes alter its environment), it converts itself into sporangia--globs or balls made up of spores. In some kinds of slime molds, the sporangia have stems; in others the stem is missing; in still others a large, single sporangium is developed. How, exactly, the spores are dispersed is unclear to me--but eventually, a single spore germinates, becomes an amoebalike thingy that may or may not have a flagellum, hooks up with some other amoebalike thingies and becomes a zygote, which eventually grows into a plasmodium.

More Information

I have oversimplified things, of course, and left out a host of subtleties and divergences. For more thorough (and more competent!) information on slime molds, check out the following:

PhysarumPlus - "An Internet Resource for Students of Physarum polycephalum and Other Acellular Slime Molds"

Introduction to the Slime Molds - At Berkeley

Fuligo septica, the Dog Vomit Slime Mold - At Tom Volk's Fungi

Hemitrichula serpula, the Pretzel Slime Mold - At Tom Volk's Fungi

Hunting Slime Molds - At Smithsonian Magazine


Lycogala epidendrum

Sporangia: Pinkish to brownish balls or cushions on wood, filled with pink paste. Plasmodium: Reddish mass.

Lycogala epidendrum

Lycogala epidendrum

Stemonitis splendens

Sporangia: Hundreds of tiny brown cylinders on short, black stems. Plasmodium: White mass.

Stemonitis splendens

Fuligo septica

Fuligo septica

This slime mold is the subject of many frantic e-mails to MushroomExpert.Com. It appears in cooler weather on dead wood or compost--then slimes its way across gardens and flower beds, looking for all the world like a patch of (sorry) vomit. See Tom Volk's Fuligo septica, The Dog Vomit Slime Mold for more information.

Unidentified orange slime mold growing with bird's nest fungi.

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Cite this page as:

Kuo, M. (2003, August). Myxomycetes: The slime molds. Retrieved from the MushroomExpert.Com Web site: