honeycomb coral slime mold

(Ceratiomyxa fruticulosa)

Conservation Status
honeycomb coral slime mold
Photo by Alfredo Colon
  IUCN Red List

not listed


not listed


not listed


Protostelid slime molds are relatively unknown and easily overlooked. They were first recognized in the early 1960s and have been little studied since. There are 36 currently accepted species, and possibly twice that number of undescribed species. Most are microscopic. Only a few are visible to the naked eye.

Honeycomb coral slime mold is the most commonly encountered protostelid slime mold and may be the most common slime mold of any kind in the world. It occurs on every continent except Greenland and Antarctica. In the United States it is common east of the Great Plains, including Minnesota, and west of the Rocky Mountains. It is absent in the arid west. It is found on shaded rotting wood of fallen logs and branches, in open, wet to moderately moist deciduous, coniferous, and mixed forests. It does not feed on the wood but on bacteria associated with the rotting wood. It can form extensive colonies one meter or more long. It is very short lived, appearing after a soaking rain and disintegrating in just a few days.

Honeycomb coral slime mold first appears as a thin, watery, translucent, mucus-like layer of protoplasm (plasmodium). It creeps across the substrate, engulfing bacteria, protozoa, and particles of nonliving organic matter. Eventually, the plasmodium fruits, converting to spore-bearing structures (sporocarps). The conversion takes about six hours.

The sporocarps are erect, slender, translucent columns appearing usually in clusters of three or more. The clusters often form patches 4 or more in diameter. The columns are 1 32 to (1 to 10 mm) long, 1 64 to 3 64 (0.5 to 1.0 mm) in diameter, and tapered. They may be branched or unbranched. When they first appear they are slimy, translucent, and usually white, rarely pink or yellow. Later, they have a frosted or powdery appearance due to a dense covering of tiny, white, spores on long, thread-like stalks. The spores may actually be one-celled sporangia.

It is not edible.


Similar Species

  No similar species in Minnesota  
Habitat and Hosts

Open, wet to moderately moist, deciduous, coniferous, and mixed forests




June through October


Distribution Map



4, 24, 26, 29, 30, 77.




Common and widespread

  Kingdom Protozoa (protozoans)  
  Phylum Mycetozoa (slime molds)  
  Class Protosteliomycetes (protostelid slime molds)  
  Order Ceratiomyxales  
  Family Ceratiomyxaceae  


Ceratiomyxa (coral slimes)  

Subordinate Taxa


honeycomb coral slime mold (Ceratiomyxa fruticulosa ssp. arbuscula)

honeycomb coral slime mold (Ceratiomyxa fruticulosa f. flava)

honeycomb coral slime mold (Ceratiomyxa fruticulosa var. fruticulosa)

honeycomb coral slime mold (Ceratiomyxa fruticulosa var. porioides)




Byssus fruticulosa

Ceratiomyxa mucida

Ceratium hydnoides

Ceratium porioides

Clavaria byssoides

Clavaria puccinia

Flora carniolica

Isaria mucida

Tremella hydnoidea


Common Names


coral slime

coral slime mold

honeycomb coral slime mold

icicle fairy fans (Australia)









A spore bearing structure, as of a fern, moss, or slime mold. Plural: sporangia.


Visitor Photos

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Alfredo Colon

    honeycomb coral slime mold      
MinnesotaSeasons.com Photos





Jules Cimon



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Other Videos
  Ceratiomyxa fruticulosa sporangia development
Daniel Brunner

Published on Oct 17, 2010

Time lapse video of the slime mold Ceratiomyxa fruticulosa var. poroides developing sporangia. Original time approx. 24 h

  Ceratiomyxa fruticulosa (O.F. Müll.) T. Macbr. 1899
The wonderful world of mycology

Published on Jun 5, 2018

Ceratiomyxa fruticulosa

Lekeitio, Bizkaia


Hábitat: madera de pino en descomposición

  Ceratiomyxa fruticulosa, the coral slime mold

Published on May 28, 2011

Not actual a fungus but a protist, this beautiful slime mold was found in South Woods Park, Shoreline, WA, USA, 5/28/11




Visitor Sightings

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  Alfredo Colon

Location: Woodbury, Minnesota

honeycomb coral slime mold  
MinnesotaSeasons.com Sightings






Created: 1/30/2019

Last Updated:

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